Step 3 Sample Test Answers + Explanations 2026
USMLE STEP 3 Free 137 Explanations
Updated June 2026
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Updated as of June 2026
Here are the detailed explanations of the new Free 137 NBME STEP 3 Sample Test Questions so you don’t waste your time trying to find the correct answers and explanations. We had our expert USMLE tutors who scored 260+ on their exams refine these answers and explanations for you so you can spend your valuable time learning!
You can download the Free 137 STEP 3 Sample Test Questions on the USMLE website here. The order of answers and explanations here is based on the online NBME platform (not the pdf) as of June 2026.
Table of Contents
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Block 1
Question 1:
The correct answer is E. This 55-year-old man has symptoms and physical findings suggestive of aortic regurgitation (AR). The patient’s bounding pulses, widened pulse pressure, displaced point of maximal impulse (PMI), and a diastolic decrescendo murmur are classic for AR. Transthoracic echocardiography (TTE) is the best initial test to confirm the diagnosis, assess the severity, and evaluate for underlying causes.
Aortic Regurgitation (AR):
Pathophysiology: Backflow of blood into the left ventricle during diastole, leading to left ventricular volume overload and eventual dilation.
Clinical Features: Fatigue, exertional dyspnea, chest discomfort (due to increased myocardial oxygen demand). Bounding pulses, wide pulse pressure, displaced PMI, and diastolic murmur.
Diagnosis: TTE is the gold standard for diagnosing AR, assessing valve anatomy, and determining the degree of regurgitation.
Management:
Mild AR: Medical management (e.g., afterload reduction with ACE inhibitors or calcium channel blockers).
Severe AR: Surgery if symptomatic or evidence of left ventricular dysfunction.
Incorrect answers:
A. Arterial brachial index of the lower extremity: Used to assess peripheral arterial disease, not relevant for AR.
B. Coronary angiography: Indicated for suspected coronary artery disease, which is not evident here.
C. Pulmonary function testing: Not related to cardiac symptoms or findings.
D. Renal ultrasonography: No indication of renal pathology or hypertension secondary to renal artery stenosis.
Question 2:
The correct answer is E. This 16-year-old patient exhibits academic decline and cannabis use. The physician must balance maintaining confidentiality with ensuring the patient receives appropriate support. A non-judgmental approach that focuses on the effects of cannabis use on functioning encourages trust and opens the door for collaborative problem-solving. Offering to facilitate communication with the mother ensures that the patient receives family support without breaching confidentiality. Adolescents often minimize the impact of substance use. Maintaining the adolescent’s confidentiality is essential for maintaining a trusting physician-patient relationship.
Incorrect answers:
A. “I am worried about your cannabis use…”: This approach is passive and delays intervention, missing an opportunity to engage the patient constructively.
B. “I can give you a telephone number for enrollment…”: Providing a referral without addressing the patient’s concerns minimizes the physician’s role in the initial conversation.
C. “Cannabis is bad for your brain…”: Lecturing the patient risks alienating them and does not foster a collaborative approach.
D. “Because you are not actually using this…”: Dismissing the problem undermines the seriousness of the patient’s substance use and its impact on functioning.
Question 3:
The correct answer is C. This patient with severe COPD and a do-not-resuscitate (DNR) order is requesting removal of noninvasive positive pressure ventilation (NIPPV). The appropriate next step is to clarify her goals of care and confirm that her wishes align with her documented advance directive. Since the directive appears unclear, engaging her in a detailed discussion ensures she understands the implications of her decision.
When a patient’s advance directive is unclear or does not fully address their current situation, it is essential to have a direct and empathetic discussion to clarify their goals of care and document their updated preferences. This ensures that medical interventions align with the patient’s values and wishes.
Incorrect answers:
A. This approach does not adequately address her current concerns or explore her preferences.
B. The patient is competent and can make decisions herself, so involving the family is unnecessary unless she requests it.
D. This contradicts the patient’s initial decision to decline intubation.
E. There is no evidence of impaired decision-making capacity, so this step is not warranted.
Question 4:
The correct answer is C. The study compared emergency portacaval shunt (EPCS) with endoscopic sclerotherapy (EST) in patients with cirrhosis and acute bleeding esophageal varices. One of the significant findings was a reduction in recurrent portal-systemic encephalopathy (PSE) with EPCS (15%) compared to EST (35%). Based on the abstract, the number needed to treat (NNT) to prevent one case of recurrent PSE is calculated using the relative risk reduction (RRR):
RRR = (35% – 15%) / 35% = 20% / 35% ≈ 0.57.
NNT = 1 / Absolute Risk Reduction (ARR) = 1 / (35% – 15%) = 1 / 0.20 = 5.
Therefore, approximately 5 patients must be treated with EPCS instead of EST to prevent one case of recurrent PSE.
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Question 5:
The correct answer is B. The study’s generalizability is limited by the fact that emergency portacaval shunt (EPCS) is a technically demanding procedure requiring specialized expertise and facilities, making it accessible only at tertiary or specialty centers. This limits its widespread application, particularly in smaller or rural hospitals.
Factors limiting generalizability:
EPCS requires highly skilled surgeons and advanced equipment.
Patients in community settings may not have timely access to this intervention.
The study was conducted at a single tertiary care center, further restricting its applicability to other settings.
Incorrect answers:
A. The allocation was concealed: This ensures validity, not generalizability.
C. The follow-up period was too short: The study had a follow-up of up to 17 years, which is sufficient.
D. The patients were not blinded: Blinding may be difficult in surgical trials but does not impact generalizability.
E. Unmeasured confounders were not controlled by the study design: The study design appears rigorous, with randomization and concealed allocation.
Question 6:
The correct answer is B. The table in the abstract shows that the mean number of hospital readmissions for variceal bleeding requiring transfusion was significantly lower in patients undergoing EPCS (0.4) compared to those receiving EST (6.8). This highlights the superior efficacy of EPCS in controlling bleeding and preventing hospitalizations.
Key findings supporting the answer:
EPCS patients had significantly fewer readmissions compared to EST patients.
The difference in efficacy is statistically significant (P < .001).
Incorrect answers:
A. This is not supported by the abstract; survival differences are clearly significant.
C. EPCS improves survival, especially for patients in Child-Pugh classes A and B.
D. The study describes appropriate randomization and concealed allocation, ensuring validity.
Question 7:
The correct answer is B. This 4-year-old boy presents with weight loss, fatigue, and hyponatremia with normal potassium levels. His physical exam and laboratory findings suggest secondary adrenal insufficiency due to chronic suppression of the hypothalamic-pituitary-adrenal (HPA) axis, likely caused by long-term glucocorticoid therapy for asthma. Prolonged use of corticosteroids suppresses the release of corticotropin-releasing hormone (CRH) from the hypothalamus and ACTH from the pituitary gland, leading to adrenal atrophy and insufficient endogenous cortisol production.
Cortisol plays a critical role in maintaining vascular tone, blood glucose levels, and electrolyte balance. In secondary adrenal insufficiency, the lack of ACTH leads to low cortisol production, but aldosterone secretion (regulated by the renin-angiotensin-aldosterone system) remains intact. This explains the hyponatremia (caused by water retention due to cortisol deficiency) without hyperkalemia, distinguishing it from primary adrenal insufficiency (e.g., Addison disease). Management involves gradual tapering of corticosteroids to allow recovery of the HPA axis and, in acute situations, replacement of hydrocortisone or other glucocorticoids.
Incorrect answers:
A. Decreased activity of 21-hydroxylase enzyme: Seen in congenital adrenal hyperplasia, characterized by hyperkalemia, hyponatremia, and virilization in severe cases, which are absent here.
C. Decreased production of antidiuretic hormone (ADH): Causes diabetes insipidus with hypernatremia and dilute urine, not hyponatremia.
D. Increased aldosterone production: Leads to primary hyperaldosteronism (e.g., Conn syndrome), causing hypokalemia and hypertension, not the findings seen in this patient.
E. Increased insulin production: Associated with hypoglycemia, which is not relevant to this case.
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Question 8:
The correct answer is E. This 64-year-old woman presents with acute shortness of breath, tachycardia, and hypoxemia. She has a history of chronic obstructive pulmonary disease (COPD) and recently underwent inguinal hernia repair, which places her at increased risk for venous thromboembolism (VTE) due to prolonged immobility and the hypercoagulable state associated with recent surgery. Despite clear lung fields and no evidence of pneumonia or heart failure on imaging, her elevated D-dimer suggests a thrombotic process, most consistent with a pulmonary embolism (PE).
Pulmonary embolism occurs when a thrombus, usually originating from the deep veins of the legs, dislodges and embolizes to the pulmonary arteries, causing ventilation-perfusion mismatch and impaired oxygenation. Classic symptoms include acute onset dyspnea, pleuritic chest pain, and tachycardia. Risk factors include surgery, immobility, cancer, and hypercoagulable states. While diagnostic imaging (e.g., CT pulmonary angiography) is often required for confirmation, an elevated D-dimer supports the presence of a thrombotic process. Prompt anticoagulation is the cornerstone of management, aiming to reduce clot propagation and prevent further embolization.
Incorrect answers:
A. COPD exacerbation: While COPD exacerbations can cause dyspnea, they are usually accompanied by wheezing, increased sputum production, or infectious symptoms, none of which are present here. Normal lung sounds also argue against this diagnosis.
B. Heart failure: The absence of bilateral rales, peripheral edema, or significant elevation in BNP makes heart failure unlikely. The patient’s BNP is within normal limits for her age.
C. Pneumonia: Pneumonia typically presents with fever, productive cough, and radiographic consolidation, none of which are evident in this patient.
D. Pneumothorax: Pneumothorax causes acute dyspnea with decreased or absent breath sounds on the affected side. This patient has clear lung fields bilaterally, ruling out this diagnosis.
Question 9:
The correct answer is C. The question presents two tests, A and B, with their respective receiver operating characteristic (ROC) curves. Test A’s curve lies above Test B’s curve in the low false-positive rate range (left side of the graph), indicating that Test A is more accurate in this range. Accuracy is determined by the area under the curve (AUC), and in this specific segment, Test A demonstrates higher sensitivity for lower false-positive rates compared to Test B.
ROC curves plot sensitivity (true positive rate) against 1-specificity (false positive rate) and help compare diagnostic tests. The closer the curve is to the upper-left corner, the more accurate the test. AUC provides a single measure of overall test performance; a higher AUC corresponds to better test accuracy. When assessing tests for different clinical scenarios, it is crucial to consider the acceptable trade-off between sensitivity and specificity, depending on the condition being diagnosed.
Question 10:
The correct answer is E. This 19-year-old college student presents with fever, chills, headache, nonproductive cough, macular rash with petechiae, and generalized weakness. On physical exam, erythematous macular lesions with petechiae are observed on the palms, soles, legs, and thighs. Laboratory findings include a mildly elevated white blood cell count with a left shift, thrombocytopenia, and cerebrospinal fluid (CSF) with a high opening pressure, slightly elevated protein, and normal glucose. These findings, combined with his geographic location (Western North Carolina) and occupational exposure (greenskeeper), are highly suggestive of Rocky Mountain spotted fever (RMSF) caused by Rickettsia rickettsii.
RMSF is a tick-borne illness transmitted by the Dermacentor species of ticks. It is commonly found in the southeastern and south-central United States. The hallmark features of RMSF include fever, headache, myalgia, and a characteristic rash that typically starts on the wrists and ankles and spreads centrally, often involving the palms and soles. The infection leads to vascular endothelial damage, resulting in increased vascular permeability, hypovolemia, and organ dysfunction. Diagnosis is clinical, as early recognition and treatment are critical to prevent severe complications, such as encephalitis, pulmonary edema, and disseminated intravascular coagulation.
Question 11:
The correct answer is D. This 19-year-old pregnant woman’s history of continued smoking during pregnancy significantly increases the risk of sudden infant death syndrome (SIDS) for her infant. Maternal smoking is the most critical modifiable risk factor for SIDS.
SIDS and maternal smoking: Smoking during pregnancy exposes the fetus to nicotine and other harmful chemicals that can impair autonomic regulation, increasing SIDS risk. Second-hand smoke after birth compounds the risk. Risk reduction strategies include smoking cessation, safe sleep practices (e.g., supine sleeping position), and breastfeeding.
Other Risk Factors for SIDS:
- Maternal/antenatal:
o Substance use: Cigarettes, alcohol, recreational drugs.
o Maternal age <20.
o Inconsistent prenatal care.
- Infant-related:
o Prematurity or low birth weight.
o Unsafe sleep environment: Prone/side sleeping, soft bedding, or bed-sharing.
o Smoke exposure (maternal or secondhand).
Incorrect answers:
A. Employment status: Unemployment is associated with socioeconomic challenges but is not a direct risk factor for SIDS.
B. History of cocaine use: The patient’s urine screening was negative, and cocaine use is not a primary risk factor for SIDS.
C. Lack of breastfeeding: While breastfeeding reduces SIDS risk, it is not as significant as maternal smoking.
Question 12:
The correct answer is B. his 75-year-old man presents with fever, pleuritic chest pain, cough producing rust-colored sputum, and consolidation in the left lower lobe, suggestive of left-sided lobar pneumonia. His symptoms worsen when he is lying on his left side, likely due to the effects of gravity on the consolidated lung. In this position, blood flow is diverted to the left lung, which has impaired oxygenation due to the consolidation, worsening the ventilation-perfusion mismatch and increasing the A-a gradient, leading to hypoxemia. When the patient is rolled to his right side, gravity helps redistribute the blood flow to the right lung, which is likely less affected by the pneumonia and is better aerated. Positional changes that favor the unaffected lung (right side in this case) can reduce the mismatch in ventilation and perfusion caused by the consolidated lung.
Incorrect answers:
A. Pulmonary embolism typically presents with sudden onset dyspnea, tachypnea, hypoxemia, and pleuritic chest pain. However, the findings of consolidation on chest x-ray, rust-colored sputum, and the gradual onset of symptoms are more indicative of pneumonia rather than a pulmonary embolism.
C. Left ventricular filling abnormalities, such as those seen in restrictive cardiomyopathy or tamponade, can cause positional symptoms, but they would not explain the focal lung findings (consolidation) or improvement with positional changes specific to pneumonia.
D. While a large pleural effusion or consolidation could restrict diaphragmatic motion, it would cause more gradual changes in breathing and wouldn’t result in the rapid improvement in symptoms seen here.
E. While pleural fluid shifts with position, the fluid doesn’t increase; it redistributes. The immediate symptom improvement suggests that the relief is due to a redistribution of blood flow, not the increase of pleural effusion. Also, the chest x-ray does not show any evidence of pleural effusion.
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Question 13:
The correct answer is C. This 12-year-old girl with a seizure disorder is requesting a dose of carbamazepine and a prescription refill. However, since the patient is a minor and her aunt is not a legal guardian, the physician is obligated to contact the mother to obtain informed consent. Treatment without guardian consent is permissible only in emergency situations where the child’s life or health is at immediate risk, which is not the case here.
Key Considerations in Minors:
Informed Consent: Legal guardians (usually parents) must provide consent for non-emergent treatment in minors.
Emergencies: In life-threatening situations (e.g., status epilepticus), treatment can proceed without consent to protect the minor’s health.
Non-Emergent Situations: Physicians must attempt to contact the parent/guardian for consent, even if the child requests treatment.
Application in This Case: Since the patient is stable, the focus should be on obtaining consent before administering medication or writing a prescription. The mother’s consent ensures adherence to legal and ethical obligations.
Incorrect answers:
A. Administer the dose of carbamazepine and provide a prescription: This action requires parental consent in non-emergency situations.
B. Administer the dose of carbamazepine but do not provide a prescription: Both actions require guardian consent.
D. Do not contact the mother but request that the aunt sign a consent form: The aunt is not legally authorized to provide consent.
E. Provide a prescription, but do not administer the dose of carbamazepine: Writing a prescription also requires parental consent.
Question 14:
The correct answer is D. This patient presents with symptoms and physical findings consistent with osteoarthritis (OA), including joint pain, morning stiffness lasting less than 30 minutes, and bony enlargement. OA is characterized by the progressive loss of articular cartilage, leading to bone remodeling. X-ray findings commonly include joint space narrowing, subchondral sclerosis, osteophyte formation, and bony cysts.
OA is the most common joint disorder, especially in weight-bearing joints like the knees. Risk factors include age, obesity, prior joint injury, and mechanical stress. Radiologic findings reflect structural changes, and treatment involves weight loss, physical therapy, and pain management with NSAIDs or acetaminophen.
Incorrect answers:
A. Bone demineralization and erosions: These findings are characteristic of inflammatory conditions like rheumatoid arthritis, not OA.
B. Soft tissue swelling, sclerotic joint margins, and large cystic erosions: This suggests crystal-induced arthritis (e.g., gout), which does not match this patient’s chronic presentation.
C. Soft tissue swelling with no evidence of cartilage or bone destruction: This is typical of inflammatory arthritis in its early stages, not OA.
E. No abnormal findings: This is incorrect as OA typically has characteristic x-ray findings, including joint space narrowing and osteophytes.
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Question 15:
The correct answer is B. This 54-year-old woman presents with recurrent upper abdominal pain, nausea, and burning throat sensations, which have not improved despite recommended lifestyle modifications and medication adherence. She is preoccupied with her symptoms and requests an endoscopy, convinced that she has Barrett esophagus after researching online. Her anxiety and preoccupation with her health, as well as frustration with her symptoms, suggest a significant emotional component to her condition. The most appropriate next step is to explore her goals and expectations regarding treatment. This approach can help build rapport, address underlying concerns, and provide reassurance.
In patients with medically unexplained symptoms or excessive health-related anxiety, effective communication is key to management. It is important to validate the patient’s concerns, avoid unnecessary diagnostic tests, and provide reassurance without dismissing their symptoms. By understanding her goals, the physician can guide discussions toward realistic expectations, address misconceptions (e.g., overemphasis on Barrett esophagus), and encourage evidence-based treatment strategies.
Incorrect answers:
A. Ask the patient if she would like to see a specialist: Referring to a specialist without first addressing her emotional and cognitive concerns may reinforce her anxiety and focus on diagnostic procedures.
C. Ask the patient to further explain why she thinks she has Barrett esophagus: This may validate her fixation on a self-diagnosis rather than addressing her underlying anxiety and treatment expectations.
D. Discuss why the patient has not made the suggested changes to her diet and exercise: While lifestyle factors contribute to symptoms, this approach may appear dismissive or critical.
E. Encourage the patient to describe how she feels about having an unresolved medical condition: While important, this step is secondary to understanding her treatment goals.
Question 16:
The correct answer is C. This patient presents with generalized pruritus, recent use of oxycodone, and no significant physical findings apart from skin excoriations. Pruritus is a well-documented side effect of opioid therapy, including oxycodone. This side effect occurs due to opioid-induced histamine release from mast cells, leading to an itch sensation. The histamine release is independent of an allergic reaction and does not require discontinuation of the medication unless the pruritus is intolerable or unmanageable.
Incorrect answers:
A. Exacerbation of psoriasis: Psoriasis can cause pruritus, but it typically presents with characteristic erythematous, scaly plaques, which are not seen in this patient, and there’s no sign of psoriasis exacerbation.
B. Obstruction of the common bile duct: This typically causes jaundice and dark urine due to biliary obstruction, which isn’t consistent with this patient’s presentation or urinalysis findings.
D. Tamsulosin therapy: Tamsulosin, an alpha-blocker, can cause orthostatic hypotension or dizziness but is not commonly associated with pruritus.
E. Ureteral obstruction: While ureteral obstruction can lead to hematuria and pain, it would not typically cause generalized pruritus; the cause of pruritus is more likely related to the medication or another systemic issue.
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Question 17:
The correct answer is A. This patient presents with mild scleral icterus and a palpable epigastric mass, which are concerning for pancreatic malignancy, such as pancreatic adenocarcinoma. A CT scan of the abdomen is the most appropriate initial diagnostic test because it provides detailed imaging of the pancreas and surrounding structures to identify tumors, metastases, or biliary obstruction.
Pancreatic cancer often presents with nonspecific symptoms, such as anorexia, abdominal discomfort, or jaundice. A CT scan is the gold standard for initial evaluation, as it can identify mass lesions, ductal dilation, and vascular involvement. Further imaging, such as endoscopic ultrasound or MRI, may be used for staging or obtaining a tissue diagnosis.
Incorrect answers:
B. Determination of serum amylase and lipase concentrations: These are elevated in acute pancreatitis but are not helpful in diagnosing pancreatic cancer.
C. Endoscopic retrograde cholangiopancreatography: This is useful for biliary interventions but is invasive and not the first-line diagnostic test for a pancreatic mass.
D. HIDA scan: This is used to evaluate gallbladder function, which is not relevant in this case.
E. Upper gastrointestinal barium study: This is used for esophageal or gastric pathologies but does not provide imaging of the pancreas.
Question 18:
The correct answer is B. This patient presents with severe abdominal pain, fever, and physical findings consistent with acute mesenteric ischemia. Laboratory findings of metabolic acidosis and leukocytosis further support this diagnosis. The patient’s abdominal X-ray shows dilated loops of bowel, which is indicative of disruption of peristaltic activity secondary to ischemia. On surgical resection, histopathology in acute ischemic colitis typically demonstrates coagulative necrosis of the mucosa and submucosa due to hypoperfusion. In some cases, full-thickness necrosis may occur if ischemia is severe.
Incorrect answers:
A. Caseating granulomatous inflammation with serosal fibrous adhesions: This is seen in conditions like tuberculosis or Crohn disease, but the acute presentation, along with the patient’s risk factors, suggests ischemia rather than chronic granulomatous disease.
C. Neutrophilic infiltrates in the mucosa with venous congestion and edema: This is more typical of acute colitis or infection (eg, inflammatory bowel disease), not ischemia, where more severe necrosis occurs due to vascular compromise.
D. Patchy mucopurulent exudate with exploding glandular crypts: This describes a pattern seen in infectious colitis or inflammatory bowel disease but does not fit the acute ischemic injury seen in mesenteric ischemia.
E. Transmural chronic inflammation with ulcerations extending into submucosa: This is a hallmark of chronic inflammatory bowel diseases like Crohn disease, but this patient’s acute presentation and vascular issues point to ischemic infarction instead.
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Block 2
Question 19:
The correct answer is B. Discrepancies in oxygen administration arise from unclear protocols. Standardizing orders ensures consistent care and reduces the risk of under- or over-administration.
Standardized protocols:
- Include clear titration guidelines.
- Prevent variability in physician and nurse practices.
- Enhance patient safety.
Implementation:
- Provide staff training on standardized protocols.
- Regular audits to ensure adherence.
Incorrect answers:
A. Conducting an in-service program: Useful but does not address systemic issues like unclear orders.
C. Encouraging nurses to refrain from adjusting therapy: Discourages autonomy without providing clear guidelines.
D. Requiring nurses to enter verbal orders: Increases administrative burden and risk of miscommunication.
E. Requiring calls for deviation: Inefficient and delays care.
Question 20:
The correct answer is C. The findings in the question describe a 29-year-old woman with HIV infection who is asymptomatic, has an undetectable viral load, and is considering pregnancy. The key consideration here is understanding the risk of perinatal HIV transmission. A maternal viral load is the strongest determinant of this risk. With effective antiretroviral therapy (ART), achieving an undetectable viral load minimizes the likelihood of transmission to less than 1%.
HIV can be transmitted from mother to child during pregnancy, delivery, or breastfeeding. The most critical factor influencing transmission is the maternal plasma HIV RNA level. With appropriate ART, the risk of transmission during delivery is exceedingly low. In addition, cesarean delivery may be recommended if the viral load is not adequately suppressed near term. Avoidance of breastfeeding is also crucial in preventing transmission.
Incorrect answers:
A. This statement is not directly related to perinatal transmission risk. Transmission is more closely associated with maternal viral load and interventions.
B. Intrapartum transmission does account for a substantial portion of cases, particularly without ART, but this statement doesn’t address the most critical determinant—maternal viral load.
D. While acute HIV infection during pregnancy is associated with higher transmission risk, this statement is less relevant in a patient with an undetectable viral load.
E. This is incorrect because cesarean delivery may reduce the risk of perinatal transmission in women with detectable viral loads.
Question 21:
The correct answer is F. This 24-year-old woman presents with recurrent episodes of irritability, insomnia, and mood swings that seem to occur in a cyclical pattern lasting 2–3 weeks. Her symptoms are likely related to her menstrual cycle, and timing of symptoms is crucial to differentiate between premenstrual dysphoric disorder (PMDD) and other mood disorders.
Key Features of PMDD:
Symptoms typically occur in the luteal phase (1–2 weeks before menses) and resolve with the onset of menstruation. Symptoms include mood changes, irritability, fatigue, insomnia, and physical symptoms (e.g., bloating, breast tenderness). Diagnosis relies on a clear temporal relationship with the menstrual cycle.
Next Steps:
Ask the patient to track her symptoms over 2–3 cycles to confirm the timing and relationship to menstruation. Management includes lifestyle modifications, SSRIs, and hormonal therapy (e.g., oral contraceptives).
Incorrect answers:
A. Carbohydrate intake: Not directly related to her mood or insomnia symptoms.
B. Coital frequency: Unrelated to her cyclic mood swings.
C. Frequency of physical activity: May impact overall well-being but is not the key history for this presentation.
D. History of psychological trauma: Relevant in other mood disorders but less likely with clear cyclic symptoms.
E. Stress level: Affects mood but does not explain the cyclic nature of her symptoms.
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Question 22:
The correct answer is C. This 18-year-old woman seeks a prescription for Essepro XL, a medication indicated for attention-deficit/hyperactivity disorder (ADHD), to improve her academic performance and lose weight. However, the patient does not have a confirmed diagnosis of ADHD, and self-diagnosis or symptom exaggeration is common in patients seeking stimulants for academic or weight-loss purposes. Moreover, prescribing stimulant medication without a clear clinical indication risks misuse and potential side effects.
Stimulant medications like Essepro XL (focopheridate sodium) are controlled substances with abuse potential. They are indicated for ADHD and sometimes narcolepsy, but not for enhancing academic performance or weight loss. Off-label use can lead to dependency, cardiovascular side effects, and other complications. Physicians must carefully evaluate patients’ symptoms and consider non-stimulant therapies or behavioral interventions when the clinical picture is unclear.
Incorrect answers:
A. There is no evidence the patient is on other stimulants, making this incorrect.
B. The presence of a midsystolic click suggests mitral valve prolapse (MVP), which is typically benign and not a contraindication for stimulant use. However, it does warrant careful consideration when prescribing stimulants due to the potential for cardiovascular side effects, such as palpitations or arrhythmias. This is not the primary reason for not prescribing the medication in this case.
D. While this is a possibility, it is speculative and not the primary reason for avoiding prescribing the medication.
E. While true, the focus here is the lack of clinical indication for prescribing the medication, not weight loss efficacy.
Question 23:
The correct answer is F. The advertisement emphasizes that Essepro XL provides better sustained action compared to other medications in its class, including methylphenidate XL. Its improved “late afternoon performance” and long-lasting effects are noted as advantages, making its increased duration of action a key benefit. This longer effect may reduce the need for multiple daily doses, enhancing patient adherence and convenience.
Stimulant medications differ in pharmacokinetics, with some formulations offering prolonged action through controlled-release mechanisms. These medications are particularly useful for patients requiring extended symptom control, such as those managing ADHD symptoms throughout the school day and into the evening.
Incorrect answers:
A. Decreased likelihood of disrupted sleep patterns: Stimulants, including Essepro XL, commonly cause insomnia, and there is no indication that it reduces sleep disruption compared to others.
B. Decreased potential for dependency: Essepro XL, as a controlled substance, carries similar dependency risks to other stimulant medications.
C. Decreased rates of nausea and anorexia: Appetite suppression is a common side effect of stimulants, and no evidence suggests Essepro XL reduces this.
D. Increased academic performance: While stimulants improve focus in patients with ADHD, their academic benefits for non-ADHD individuals are unclear.
E. Increased availability of safety data: Essepro XL does not have more extensive safety data than other medications in its class.
Question 24:
The correct answer is D. This 63-year-old man presents with a history of transient monocular vision loss, likely due to amaurosis fugax, a transient ischemic event involving the retina. The most common etiology is retinal ischemia due to atherosclerotic emboli. These emboli usually originate from ipsilateral carotid artery. So, patients with risk factors, should be evaluated with an ultrasonography of the neck.
Amaurosis Fugax:
Pathophysiology: Typically caused by a transient embolus or hypoperfusion affecting the retinal circulation.
Presentation: Sudden, temporary monocular vision loss lasting seconds to minutes, with full resolution. Classic: Curtain descending over the visual field
Etiology: Most cases arise from embolic events (e.g., carotid artery atherosclerosis, atrial fibrillation). Other causes include retinal artery vasospasm or giant cell arteritis.
Carotid Ultrasonography: Non-invasive, highly sensitive and specific for detecting carotid artery stenosis.
Incorrect answers:
A. Fluorescein angiography of the right eye: Used to evaluate retinal vascular abnormalities, but not indicated here due to the transient nature of the event.
B. Measurement of intraocular pressures: Necessary for glaucoma, which is not suspected here.
C. Transesophageal echocardiography: Appropriate for suspected cardioembolic sources, but there is no evidence of embolism here.
E. No further evaluation is indicated: This is inappropriate, as amaurosis fugax often indicates underlying atherosclerotic disease or embolic risk that requires prompt evaluation to prevent future stroke or vision loss.
Question 25:
The correct answer is B. This 63-year-old woman developed acute kidney injury (AKI), as evidenced by rising creatinine, hyperkalemia, and oliguria. CKD, a known risk factor for AKI, predisposes patients to ischemic or nephrotoxic injury due to reduced renal reserve. The patient’s pre-existing stage 3 CKD likely contributed to her reduced ability to recover from acute stressors.
CKD is defined by a glomerular filtration rate (GFR) <60 mL/min/1.73 m² for more than 3 months. Chronic damage to nephrons reduces the kidney’s capacity to adapt to hemodynamic changes, making these patients vulnerable to AKI triggers such as volume depletion, nephrotoxins, or sepsis.
Incorrect answers:
A. Bladder catheterization: While this increases the risk of urinary tract infections, there is no evidence of infection here causing acute kidney injury.
C. Uncontrolled hypertension: Although this may contribute to chronic kidney damage, it is not the primary driver of AKI in this case.
D. Use of lisinopril: ACE inhibitors can cause AKI in volume-depleted patients, but there is no indication that lisinopril played a role here.
E. Volume depletion: The patient’s serum sodium and absence of orthostatic symptoms argue against significant volume depletion.
Question 26:
The correct answer is B. This 28-year-old man presents with dysuria and minimal urethral discharge. He is sexually active with one partner, but his symptoms are suggestive of a sexually transmitted infection (STI). The absence of significant discharge or systemic findings does not rule out gonococcal or chlamydial urethritis. A PCR test is highly sensitive and specific for diagnosing these infections, even in patients with mild or atypical presentations.
Gonococcal and chlamydial infections are the most common causes of urethritis in sexually active individuals. N. gonorrhoeae often causes purulent discharge, whereas C. trachomatis may result in a milder presentation. PCR-based testing is the gold standard due to its accuracy and ability to differentiate between pathogens, allowing for targeted treatment.
Incorrect answers:
A. Gram stain of urethral discharge before and after prostatic massage: Prostatic massage is not indicated here since the patient has urethritis symptoms, not prostatitis. Gram stain has limited sensitivity compared to PCR.
C. Urinalysis: While urinalysis can detect pyuria, it does not identify specific pathogens such as N. gonorrhoeae or C. trachomatis.
D. Urine culture and sensitivity: This is useful for bacterial UTIs, not STIs like gonorrhea or chlamydia.
E. No study, pending reevaluation of sexual history: This delays diagnosis and treatment, potentially worsening the condition and increasing the risk of transmission.
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Question 27:
The correct answer is D. This 44-year-old woman reports an increase in the duration and amount of menstrual bleeding, lasting 10 days instead of her usual six. Her symptoms of heavy menstrual bleeding are accompanied by fatigue, which may indicate anemia. On examination, she has an enlarged uterus consistent with a myomatous (fibroid) uterus previously confirmed by ultrasound. While fibroids are a common cause of heavy menstrual bleeding, an endometrial biopsy is necessary to rule out endometrial hyperplasia or carcinoma, particularly in women over 40 with abnormal uterine bleeding (AUB).
Endometrial hyperplasia and carcinoma are often associated with unopposed estrogen exposure. Risk factors include obesity, polycystic ovarian syndrome (PCOS), and chronic anovulation, all of which lead to prolonged estrogen stimulation of the endometrium without opposing progesterone. Over time, this can cause endometrial thickening, atypia, and, eventually, malignancy. An endometrial biopsy is a minimally invasive and highly sensitive method to detect hyperplasia or malignancy. Early identification and management of endometrial hyperplasia can prevent progression to carcinoma, highlighting the importance of biopsy in this clinical scenario.
Incorrect answers:
A. Colposcopy: Used to evaluate abnormal cervical cytology or visible cervical lesions, not for investigating abnormal uterine bleeding (AUB).
B. Determination of FSH/LH concentrations: Appropriate for menopause evaluation but does not help identify structural or endometrial causes of AUB.
C. Serum prolactin determination: Used for amenorrhea or galactorrhea but does not address heavy menstrual bleeding.
E. Hysteroscopy: Useful for direct visualization of intrauterine pathology but is invasive and not the first-line diagnostic test for AUB.
Question 28:
The correct answer is A. This 2-month-old boy with conjugated hyperbilirubinemia, hypoplastic gallbladder on ultrasound, and elevated direct bilirubin is consistent with biliary atresia. The microscopic hallmark of biliary atresia is bile ductular proliferation, which results from obstruction of bile flow and progressive fibrosis.
Key Features of Biliary Atresia:
Progressive fibroinflammatory obliteration of the extrahepatic bile ducts, leading to biliary obstruction. Presents with:
- Jaundice (persistent conjugated hyperbilirubinemia).
- Pale stools and dark urine (reduced bile in stool).
- Hepatomegaly (due to inflammation and fibrosis).
- Elevated direct bilirubin and liver enzymes (ALT/AST).
- Hypoplastic or absent gallbladder on ultrasound.
Pathology:
Bile ductular proliferation occurs in response to biliary obstruction and is accompanied by portal tract fibrosis and eventual cirrhosis if untreated.
Incorrect answers:
B. Centrilobular necrosis: Seen in ischemic or toxic liver injury, not in biliary obstruction.
C. Increased glycogen stores: Associated with glycogen storage diseases, not biliary atresia.
D. Intranuclear hepatocytic inclusions: Seen in viral infections (e.g., CMV, HSV), not biliary atresia.
E. Macrovesicular steatosis: Seen in conditions like nonalcoholic fatty liver disease or metabolic disorders.
Question 29:
The correct answer is E. This 68-year-old man presents with acute-onset neurological symptoms, including ataxia, dysphagia, left-sided weakness, and right facial droop. These symptoms suggest a vascular event involving both motor pathways and cranial nerves. His ataxic gait and difficulty swallowing indicate brainstem involvement, while the combination of cranial nerve deficits (drooping on the right side of the face) and motor weakness (left-sided weakness) further localizes the lesion to the posterior circulation of the brain, supplied by the vertebrobasilar system.
The vertebrobasilar system includes the vertebral and basilar arteries, which supply the brainstem, cerebellum, thalamus, occipital lobe, and parts of the temporal lobe. Ischemia in this system can cause a constellation of symptoms depending on the specific vascular territory involved. The brainstem, where cranial nerve nuclei are located, is especially vulnerable. Classic findings of vertebrobasilar ischemia include dizziness, ataxia, dysphagia, and motor or sensory deficits that often cross hemispheres (e.g., ipsilateral cranial nerve findings with contralateral motor weakness, as seen here). This pattern is due to the involvement of both descending motor pathways and cranial nerve structures.
Incorrect answers:
A. Anterior cerebral artery supplies the medial frontal and parietal lobes. Infarction causes contralateral leg weakness and personality changes, not cranial nerve deficits or ataxia.
B. Internal carotid artery supplies both the anterior and middle cerebral arteries. Lesions here would result in a combination of middle and anterior cerebral artery symptoms, such as unilateral weakness and aphasia, not brainstem symptoms.
C. Middle cerebral artery supplies the lateral portions of the frontal, parietal, and temporal lobes. Infarction typically causes hemiparesis, hemisensory loss, and aphasia (if the dominant hemisphere is affected).
D. Posterior cerebral artery supplies the occipital lobe and inferior temporal lobe. Infarction results in visual field defects (e.g., homonymous hemianopia), not brainstem dysfunction.
Question 30:
The correct answer is E. This 2-week-old newborn with trisomy 18 has significant congenital anomalies, including dysmorphic features, severe growth restriction (5th percentile weight and head circumference), and cardiac abnormalities. The prognosis is extremely poor, with most infants succumbing within the first month. Hospice care is appropriate to prioritize comfort and support for the family.
Trisomy 18 (Edwards syndrome):
Severe intellectual disability and congenital anomalies (e.g., heart defects, overlapping fingers, rocker bottom feet).
Median survival: Less than 2 weeks for neonates; <10% survive beyond the first year.
Hospice focuses on symptom management, quality of life, and family support.
Incorrect answers:
A. Admission to the hospital for a sleep apnea study: Sleep apnea evaluation is not appropriate in the context of severe, life-limiting congenital anomalies.
B. CT scan of the head: Unnecessary given the obvious clinical syndrome and poor prognosis.
C. Electroencephalography: Seizure assessment is not the priority here.
D. Referral to a cardiologist: Although the patient has a heart murmur, invasive interventions are unlikely to change outcomes.
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Question 31:
The correct answer is D. This 58-year-old man presents with an acute inferior ST-elevation myocardial infarction (STEMI) involving leads II, III, and aVF, indicative of right coronary artery occlusion. His sudden hypotension after nitroglycerin administration strongly suggests right ventricular (RV) infarction. RV infarctions reduce preload as the RV maintains venous return. Nitroglycerin further decreases preload by causing venodilation, leading to severe hypotension in this setting.
RV infarctions are a subset of inferior STEMIs and are associated with occlusion of the right coronary artery. Clinical features include:
- Hypotension with clear lung fields (no pulmonary congestion).
- Jugular venous distension due to elevated central venous pressure.
- ST-segment elevation in the right-sided precordial leads (e.g., V4R).
Management focuses on maintaining RV preload. Volume resuscitation with intravenous fluids is critical to improve cardiac output, while preload-reducing agents like nitrates should be avoided. Reperfusion therapy with percutaneous coronary intervention (PCI) or thrombolysis is essential for restoring coronary blood flow.
Incorrect answers:
A. Acute mitral regurgitation: Results in pulmonary edema, a loud systolic murmur, and severe dyspnea, none of which are present here.
B. Pericardial tamponade: Causes hypotension, distant heart sounds, pulsus paradoxus, and jugular venous distension, absent in this case.
C. Pulmonary embolism: Typically presents with sudden dyspnea, hypoxemia, and pleuritic chest pain, not ST-segment elevation.
E. Vasovagal reaction: Causes bradycardia and hypotension without ST-segment changes or infarction.
Question 32:
The correct answer is D. The study shows that the intervention group experienced a reduction in the number of inflamed joints compared to the placebo group (7 vs. 2 joints, P = 0.02). The statistical significance (P < 0.05) indicates that the results are unlikely to have occurred by chance. Clinically, this 5-joint improvement is meaningful for patients with rheumatoid arthritis, as it suggests better symptom control and improved quality of life.
Statistical significance is determined by the P value, whereas clinical significance assesses whether the magnitude of the effect is meaningful to patients. Both aspects are important for interpreting the impact of a treatment.
Question 33:
The correct answer is B. This 60-year-old woman with a history of Parkinson disease, dementia, and bipolar disorder presents with confusion, falls, and an inability to recall her current medications. The patient is unable to provide accurate information about her medication regimen, and her primary support system (her brother) is unavailable. In this situation, contacting her pharmacy is the most practical and reliable approach to confirm her medication history, ensuring safe and appropriate care.
When managing a patient with cognitive impairment who cannot recall their medications, it is critical to obtain accurate information to prevent errors such as medication omissions or overdoses. Pharmacies maintain detailed records of dispensed medications, which can provide insight into the patient’s regimen, including recent changes or refills. This step minimizes the risk of adverse drug reactions, drug interactions, or complications from untreated conditions. Once the medication list is confirmed, the clinical team can evaluate whether her symptoms (e.g., falls, confusion) are related to medication side effects, withdrawal, or progression of her underlying conditions. In cases where the pharmacy records are insufficient or unavailable, additional measures like contacting her healthcare providers or family may be necessary.
Incorrect answers:
A. Ask the police to enter the brother’s house to locate the patient’s pill bottles: This is invasive and not immediately practical. Medication bottles at the house may not reflect the patient’s current regimen or dosing schedule.
C. Observe the patient closely while continuing to try to reach her brother: Observation delays definitive care and does not address the need to confirm the medication list. The brother is unavailable, making this approach inefficient.
D. Order the medications as listed in the emergency department record from her previous visit: Relying on outdated records is risky, as medication regimens may have changed since her last visit a year ago.
E. Order serum concentrations of the medications listed on the emergency department record: Measuring serum drug levels may help confirm adherence or toxicity but does not provide comprehensive information about her full medication regimen.
Question 34:
The correct answer is B. This question addresses a scenario where African American patients are underrepresented in a research study due to reluctance to enroll. Convening a representative focus group is an appropriate step to identify barriers and address concerns related to participation. This approach demonstrates respect for the community, ensures ethical research practices, and may improve enrollment by tailoring the process to address specific concerns.
Historically, distrust of the medical research system among minority groups has arisen from unethical practices.). Researchers must engage the community through culturally sensitive strategies, transparent communication, and measures to ensure ethical conduct.
Incorrect answers:
A. Ask the institutional review board to waive informed consent: This would violate ethical principles and further erode trust.
C. Focus recruitment efforts on White patients: This approach is discriminatory and fails to address the underrepresentation of minority groups.
D. Recognize this as unavoidable and continue as is: This response neglects the ethical obligation to address barriers and promote inclusivity.
E. Require all patients to participate: Mandatory participation violates autonomy and informed consent principles.
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Question 35:
The correct answer is D. This 52-year-old man with cirrhosis presents with fever, hemorrhagic bullae, and hypotension, consistent with sepsis. His recent travel and exposure to warm seawater or ingestion of raw seafood suggest Vibrio vulnificus infection, a gram-negative bacterium commonly found in marine environments.
Vibrio vulnificus: Causes wound infections, sepsis, and bullous lesions, particularly in patients with liver disease (e.g., cirrhosis). Transmitted via contact with contaminated seawater or ingestion of raw shellfish.
Treatment: Immediate antibiotics (e.g., doxycycline + ceftriaxone). Supportive care for sepsis.
Incorrect answers:
A. Enterobacter aerogenes: Typically causes nosocomial infections, not associated with marine exposure.
B. Enterococcus faecalis: Commonly causes endocarditis or urinary infections, not associated with hemorrhagic bullae.
C. Mycobacterium marinum: Causes chronic granulomatous skin infections, not sepsis or bullous lesions.
Question 36:
The correct answer is B. This 55-year-old man with a fasting glucose of 126 mg/dL has impaired fasting glucose, placing him at risk for type 2 diabetes mellitus. Measurement of hemoglobin A1c is the most appropriate next step to confirm the diagnosis and assess long-term glucose control.
Diabetes Diagnosis (any one of the following):
- Fasting glucose ≥126 mg/dL.
- Hemoglobin A1c ≥6.5%.
- 2-hour glucose tolerance or random glucose ≥200 mg/dL
Incorrect answers:
A. Arterial blood gas values: Not indicated in a patient with no signs of acid-base disturbance or respiratory symptoms.
C. 3-hour glucose tolerance test: Used when initial tests are equivocal, but hemoglobin A1c is the preferred initial test.
D. Serum cortisol concentration: Unnecessary; there are no signs of adrenal insufficiency.
E. Serum fructosamine concentration: Reflects shorter-term glucose control (2–3 weeks) and is less commonly used than hemoglobin A1c.
Question 37:
The correct answer is D. This 3-month-old infant presents with respiratory distress characterized by head bobbing, nasal flaring, retractions, and wheezing. These symptoms are typical of bronchiolitis, a viral lower respiratory tract infection most commonly caused by RSV, particularly in children under two years old during winter. The chest X-ray findings of bilateral hyperinflation with peribronchial cuffing, combined with lymphocytosis (suggesting a viral etiology), and respiratory acidosis (low pH and elevated PCO2), further confirm the diagnosis.
RSV is the most frequent cause of bronchiolitis and pneumonia in young children. It primarily affects the small airways (bronchioles) by causing inflammation, edema, and increased mucus production, which lead to airway obstruction and impaired gas exchange. This results in wheezing, crackles, and hyperinflation, as seen on imaging. Infants with RSV bronchiolitis often develop respiratory failure due to increased work of breathing, leading to hypoxemia and hypercapnia. Management typically involves supportive care, including oxygen therapy and hydration. Routine use of bronchodilators or corticosteroids is not recommended unless there is a strong suspicion of an underlying reactive airway disease.
Differentiating RSV from bacterial or other viral infections is crucial:
Incorrect answers:
A. Haemophilus influenzae: is associated with bacterial epiglottitis or pneumonia, not diffuse bronchiolitis.
B. Herpes virus: Rarely causes bronchiolitis in infants and is associated with vesicular rashes or encephalitis, not respiratory distress.
C. Mycoplasma pneumoniae: is rare in infants and presents with patchy interstitial infiltrates in older children and adults.
E. Streptococcus pneumoniae: typically causes lobar pneumonia with focal consolidation and neutrophilic response.
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Block 3
Question 38:
The correct answer is A. This patient has multiple risk factors for impaired wound healing and complications following amputation, including diabetes mellitus, peripheral vascular disease, and prior arterial bypass surgery. A 3 cm blackened eschar on the heel suggests ischemic necrosis, a sign of severe peripheral vascular disease. Poor vascular supply to the distal extremities can lead to impaired healing, infection, and potentially limb-threatening complications. This is particularly concerning in patients with diabetes, as they are predisposed to infections due to neuropathy and hyperglycemia impairing immune function.
A well-vascularized and healthy distal limb is critical for successful ambulation with a prosthesis. The presence of ischemic tissue, as indicated by the blackened eschar, highlights poor peripheral perfusion, which would significantly hinder this patient’s ability to heal and ambulate effectively with a prosthesis.
Incorrect answers:
B. A 5-degree left hip flexion contracture: While contractures can complicate prosthetic fitting, they are typically correctable through physical therapy or surgical intervention and are less likely to impair long-term ambulation compared to critical limb ischemia.
C. An irregular pulse: An irregular pulse may indicate atrial fibrillation, which is already noted in this patient’s history. However, it does not directly affect the ability to ambulate with a prosthesis.
D. Loss of proprioception in the right great toe: While proprioception loss can complicate balance and ambulation, it is less significant than the vascular complications associated with ischemia and tissue necrosis.
Question 39:
The correct answer is B. This 21-year-old ballet dancer presents with secondary amenorrhea, a BMI of 18 kg/m², and a history of strenuous exercise and low caloric intake. These findings are characteristic of functional hypothalamic hypogonadism, which occurs due to insufficient energy availability leading to suppression of the hypothalamic-pituitary-gonadal axis.
Etiology: Caloric deficit and excessive physical activity suppress gonadotropin-releasing hormone (GnRH) secretion, leading to low levels of LH, FSH, and estradiol.
Clinical Features: Amenorrhea, low BMI, and potentially reduced bone density due to hypoestrogenism.
Management: Restore energy balance with increased caloric intake and decreased physical activity. Hormonal therapy may be required for severe hypoestrogenism to prevent osteoporosis.
Incorrect answers:
A. Addison disease: Would present with hyperpigmentation, fatigue, hypotension, and electrolyte abnormalities, which are absent here.
C. Partial hypopituitarism: Usually affects multiple pituitary hormones, not just GnRH. This patient does not have other pituitary dysfunctions.
D. Polycystic ovarian syndrome: Presents with obesity, hyperandrogenism (hirsutism, acne), and irregular periods, which are not seen in this patient.
E. Premature ovarian failure: Characterized by elevated FSH and LH levels, which are not mentioned or expected in this case.
Question 40:
The correct answer is A. This 16-year-old boy presents with watery diarrhea, abdominal cramps, and a stool specimen showing numerous 6-µm ovoid oocysts, which is characteristic of Cryptosporidium parvum, a protozoan parasite. His history of recurrent infections suggests an underlying immunodeficiency, predisposing him to opportunistic infections such as cryptosporidiosis.
Cryptosporidium is a common cause of chronic diarrhea, particularly in immunocompromised individuals, such as those with primary immunodeficiencies. The oocysts of Cryptosporidium are transmitted through contaminated water or person-to-person contact and are resistant to chlorination. Diagnosis is made by identifying oocysts in stool using acid-fast staining or antigen detection assays. In immunocompetent individuals, cryptosporidiosis typically resolves spontaneously, but in immunocompromised patients, treatment with nitazoxanide and immune restoration (if possible) are critical.
Incorrect answers:
B. Entamoeba histolytica: Causes bloody diarrhea and liver abscess, which are absent here. The stool findings are also inconsistent with E. histolytica.
C. Norovirus: Commonly causes acute viral gastroenteritis, with shorter symptom duration and no identifiable oocysts on stool microscopy.
D. Salmonella typhi: Associated with typhoid fever, which presents with systemic symptoms (fever, abdominal pain, “rose spots”), not watery diarrhea.
E. Shigella flexneri: Causes dysentery with fever and bloody diarrhea, inconsistent with this patient’s presentation.
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Question 41:
The correct answer is E. This patient has had six illnesses in the past 18 months, raising concern for an underlying immunodeficiency. Quantitative measurement of serum immunoglobulin concentrations is the most appropriate next step, as the history of recurrent sinopulmonary infections and gastrointestinal infections is highly suggestive of a humoral immunodeficiency, such as common variable immunodeficiency (CVID). Patients with CVID often have low levels of IgG, IgA, and/or IgM, impairing their ability to mount an effective immune response to infections.
Humoral immunodeficiencies are among the most common primary immunodeficiencies, typically presenting with recurrent bacterial infections of the respiratory and gastrointestinal tracts. Diagnosing a humoral immunodeficiency involves measuring serum immunoglobulin levels and confirming impaired antibody production. Management includes immunoglobulin replacement therapy to reduce the frequency and severity of infections.
Incorrect answers:
A. CD4+ T-lymphocyte count: Relevant in HIV/AIDS but unnecessary here, as there is no clinical or historical evidence of HIV.
B. CD8+ T-lymphocyte count: Typically evaluated in conjunction with CD4+ T-cell counts in HIV/AIDS or cytotoxic T-cell deficiencies, which are not suspected here.
C. Serum complement concentrations: Deficiencies in complement components (e.g., C2, C3) cause recurrent bacterial infections but are less common than humoral immunodeficiencies and unrelated to chronic diarrhea.
D. Serum interferon gamma assay: Used to diagnose latent tuberculosis or mycobacterial infections, which are not suggested by this patient’s history.
Question 42:
The correct answer is B. The graph demonstrates the receiver operating characteristic (ROC) curves of various screening tests for gestational diabetes mellitus. For screenings, we should minimize the risk of false-negative results, so the test with the highest sensitivity (curve B) should be selected.
ROC Curve Analysis:
- Sensitivity is plotted against (1 – specificity).
- The closer the curve is to the upper left corner, the better the test’s diagnostic performance.
- Curve B has the highest sensitivity, making it the most appropriate choice for this patient who prioritizes avoiding false negatives.
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Question 43:
The correct answer is C. When designing a clinical trial, particularly a phase 3 trial for the prevention of type 2 diabetes mellitus (T2DM), selecting participants at high risk for developing the condition ensures that the study is both efficient and clinically meaningful. Patients with hyperlipidemia and central obesity (abdominal fat distribution) represent a population with a significantly elevated risk of developing T2DM. This group is ideal for assessing the effectiveness of preventive medication, as the higher baseline risk increases the likelihood of observing a measurable effect of the intervention within the trial period.
Incorrect answers:
A. This group has a low risk of diabetes, which would make it inefficient for study purposes.
B. This population is too general and may include many individuals at low risk.
D. This group already meets diagnostic criteria for diabetes, making them unsuitable for a prevention study.
Question 44:
The correct answer is D. Celecoxib, a selective COX-2 inhibitor, decreases prostaglandin synthesis while sparing COX-1, minimizing gastrointestinal side effects. However, COX-2 also contributes to thromboxane A₂ production, which is involved in platelet aggregation, creating a prothrombotic state.
COX-2 inhibitors: Reduce inflammation and pain (used in osteoarthritis). Increase cardiovascular risk by disrupting prostacyclin (vasodilatory) and thromboxane A₂ (prothrombotic) balance.
Clinical relevance: Avoid in patients with cardiovascular risk factors or recent myocardial infarction.
Incorrect answers:
A. Both COX-1 and COX-2 decreasing prostanoid production: COX-2 inhibitors spare COX-1.
B. COX-1 decreasing prostacyclin production: COX-1 primarily affects gastric mucosa.
C. COX-1 decreasing thromboxane A₂ production: COX-1 is not inhibited by celecoxib.
E. COX-2 decreasing prostacyclin production: While true, the main concern is thromboxane A₂ imbalance.
Question 45:
The correct answer is E. This 56-year-old man presents with right-sided weakness, ptosis, and miosis, suggesting Horner syndrome. His smoking history and long-term exposure to tobacco are risk factors for a superior sulcus tumor (Pancoast tumor), a type of non-small cell lung cancer that arises in the apex of the lung and can compress nearby structures, including the sympathetic chain.
Horner syndrome results from disruption of the sympathetic pathway and includes ptosis (due to denervation of Müller muscle), miosis (unopposed parasympathetic input), and anhidrosis (if fibers to sweat glands are involved). Pancoast tumors may also invade the brachial plexus, causing weakness or pain in the arm. Diagnosis involves imaging (chest X-ray or CT) and biopsy for histologic confirmation.
Incorrect answers:
A. Cerebellar artery aneurysm: This would cause cerebellar symptoms such as ataxia or vertigo, not Horner syndrome.
B. Diabetic oculomotor paresis: This typically presents with ptosis and ophthalmoplegia but spares the pupil, distinguishing it from Horner syndrome.
C. Myasthenia gravis: While it can cause ptosis, it does not cause miosis or the localized findings seen here.
D. Lambert-Eaton syndrome: Associated with proximal muscle weakness and autonomic symptoms, but it does not typically cause Horner syndrome or localized signs of tumor invasion.
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Question 46:
The correct answer is C. This 56-year-old woman with untreated HIV presents with tender, swollen cervical lymphadenopathy and biopsy findings of acid-fast bacilli, consistent with a mycobacterial infection. In immunocompromised patients, Mycobacterium tuberculosis often disseminates hematogenously from a primary lung infection to distant sites, including the cervical lymph nodes. This patient’s weakened immune system, reflected by a low CD4 count (160/mm³), impairs her ability to contain the infection within the lungs, allowing for systemic spread.
Hematogenous dissemination of tuberculosis occurs more frequently in immunocompromised individuals, such as those with untreated HIV, due to impaired cell-mediated immunity. This can result in extrapulmonary tuberculosis, including tuberculous lymphadenitis, meningitis, miliary tuberculosis, and bone involvement. Cervical lymphadenitis, or scrofula, is a common presentation of extrapulmonary TB and is characterized by painless or mildly tender swelling of lymph nodes, often with overlying skin changes. Diagnosis is confirmed with lymph node biopsy showing granulomatous inflammation and acid-fast bacilli.
Incorrect answers:
A. Direct inoculation via the skin: Direct inoculation is rare for mycobacterial infections and typically occurs in cases of traumatic skin injuries, which are not mentioned in this patient’s history.
B. Direct tissue invasion from the hilar lymph nodes: Direct invasion is unlikely because the hilar nodes are located deep in the thorax, far from the cervical lymph nodes. Hematogenous or lymphatic spread is more plausible.
D. Lymphatic drainage from pharyngeal tissues: While lymphatic drainage can lead to cervical lymphadenopathy, this typically occurs with infections originating in the pharynx or oral cavity.
E. Trafficking of infected lymphocytes: Although trafficking of infected immune cells can contribute to disseminated TB, this process does not typically present as isolated cervical lymphadenopathy.
Question 47:
The correct answer is D. This 58-year-old man has uncontrolled hypertension despite being on multiple antihypertensives. The lack of improvement raises concern about medication adherence. Refill patterns provide objective data on whether the patient is filling prescriptions regularly.
Common causes of poor blood pressure control include nonadherence, secondary hypertension, or suboptimal dosing. Medication adherence is a frequent issue in chronic diseases.
Next steps: Confirm adherence through pharmacy records. Reassess patient education and address barriers (e.g., side effects, cost).
Incorrect answers:
A. Caffeine use: Minor contributor to hypertension, unlikely to explain resistance.
B. Exercise history: Important for long-term management but secondary to adherence in this scenario.
C. Frequency of fast-food consumption: May affect cardiovascular risk but does not directly explain uncontrolled hypertension.
Question 48:
The correct answer is E. This 20-year-old primigravid woman at 8 weeks of gestation presents with persistent nausea, vomiting, weight loss, and reduced urine output over two days. Her physical exam is unremarkable except for an elevated urine specific gravity (>1.030), indicating dehydration. These symptoms are consistent with hyperemesis gravidarum (HG), a severe form of nausea and vomiting during early pregnancy. Prolonged vomiting leads to dehydration, electrolyte imbalances, and prerenal azotemia (elevated serum urea nitrogen concentration), resulting from reduced renal perfusion due to volume depletion.
Dehydration increases the kidney’s reabsorption of urea and sodium to conserve water, causing a rise in serum urea nitrogen and creatinine levels. Prerenal azotemia is characterized by an increased blood urea nitrogen (BUN)-to-creatinine ratio (>20:1). The condition is typically self-limited but can cause significant morbidity if left untreated. Management focuses on correcting dehydration with intravenous fluids and electrolyte repletion. In severe cases, antiemetics like ondansetron or metoclopramide are used to reduce symptoms. Early identification and treatment are essential to avoid complications such as severe malnutrition or Wernicke encephalopathy.
Incorrect answers:
A. Leukocyte count: While leukocytosis can occur in infections, there is no evidence of infection (e.g., fever, chills, or systemic signs) in this patient.
B. Serum ALT and AST activities: Elevated liver enzymes may be seen in conditions like acute fatty liver of pregnancy or HELLP syndrome, but these occur in later stages of pregnancy and are not associated with isolated vomiting and dehydration.
C. Serum calcium concentration: While prolonged vomiting may rarely lead to hypocalcemia, it is not typically seen in HG. Dehydration and azotemia are more prominent laboratory abnormalities.
D. Serum glucose concentration: Hypoglycemia is not a hallmark of HG. Blood glucose is usually normal or slightly decreased in patients with prolonged fasting or vomiting.
F. No abnormality is likely: Dehydration and prerenal azotemia are common in HG, so laboratory abnormalities such as elevated serum urea nitrogen are expected.
Question 49:
The correct answer is D. This patient presents with abdominal pain, diarrhea, yawning, diaphoresis, dilated pupils, and hyperactive bowel sounds. These findings are classic for opioid withdrawal, which occurs when a patient with opioid dependence discontinues use or is unable to access opioids. Symptoms typically begin within hours to days of cessation and include flu-like symptoms, autonomic hyperactivity, and gastrointestinal distress.
Opioid withdrawal is non-life-threatening but highly uncomfortable for the patient. Management involves supportive care and, if needed, pharmacologic interventions like buprenorphine or methadone to alleviate symptoms. Clonidine may also be used to reduce autonomic symptoms.
Incorrect answers:
A. Cannabinoids: Cannabinoid withdrawal is usually mild and characterized by irritability, anxiety, insomnia, and decreased appetite. The patient’s severe gastrointestinal symptoms are inconsistent with this.
B. Cocaine: Cocaine withdrawal presents with fatigue, hypersomnolence, depression, and increased appetite, rather than the autonomic symptoms described here.
C. Methamphetamine: Methamphetamine withdrawal leads to significant fatigue, increased sleep, and depression. The symptoms described in this case are not typical.
Question 50:
The correct answer is A. This 53-year-old man with acute pancreatitis has developed new-onset labored breathing, fever, and decreased breath sounds on the left lung base. These findings are suspicious for a left-sided pleural effusion or pneumonia, both of which are common complications of pancreatitis. A chest X-ray is the most appropriate next step to evaluate these findings.
Pancreatitis-Related Complications:
Pleural Effusion: Often exudative and due to inflammation of the diaphragm or fistula formation.
Pneumonia: Occurs secondary to impaired respiratory mechanics from pain or systemic inflammation.
Incorrect answers:
B. Determination of cardiac enzyme activity: No clinical evidence suggests myocardial ischemia.
C. Echocardiography: Unnecessary unless cardiac tamponade or pericardial effusion is suspected, which is not the case here.
D. Ultrasonography of the chest: May be used to evaluate pulmonary edema but is less accessible than chest X-ray.
E. Ventilation-perfusion lung scans: Indicated for pulmonary embolism evaluation, not suggested here.
Question 51:
The correct answer is C. This 11-year-old boy’s parents are hesitant about the HPV vaccine due to misconceptions about its necessity. Educating the parents about HPV transmission and the vaccine’s role in preventing cancer is essential. HPV can be transmitted even in the context of monogamous relationships if one partner carries the virus.
HPV vaccine counseling:
Indications: Recommended for both boys and girls aged 9–26, ideally before sexual debut.
Benefits: Prevents infection with high-risk HPV strains responsible for cervical, anal, and oropharyngeal cancers.
Addressing concerns: Reassure parents about vaccine safety and long-term benefits.
Incorrect answers:
A. Misleading; HPV vaccines are extremely safe, and this phrasing may amplify fears.
B. Does not address the parents’ specific concern about their son’s risk of exposure.
D. Deferring vaccination reduces the opportunity for maximum efficacy.
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Question 52:
The correct answer is A. This 77-year-old man with sepsis and gangrene refuses life-saving amputation despite understanding the risks. He is alert, oriented, and has decision-making capacity. In such cases, respecting the patient’s autonomy is paramount, even if the physician disagrees with the decision.
Informed consent requires that patients understand the risks, benefits, and alternatives to a proposed treatment. As long as the patient demonstrates capacity (i.e., can understand, deliberate, and communicate their decision), their wishes must be respected. Ethical principles emphasize patient autonomy as a cornerstone of medical decision-making.
Incorrect answers:
B. Consult the hospital bioethics department: This is unnecessary as the patient has clearly expressed their wishes and demonstrated decision-making capacity.
C. Obtain consent for amputation from both sons: The patient’s sons do not have legal authority to make decisions when the patient has capacity.
D. Obtain consent for amputation from the younger son: Similarly, this is not appropriate because the patient retains autonomy.
F. Review any additional instructions in the patient’s living will: The patient actively makes decisions and does not rely on a living will for guidance.
Question 53:
The correct answer is D. This patient presents with signs of right heart failure (elevated JVP, peripheral edema) and hypoxemia (oxygen saturation of 84%). The chest X-ray findings, combined with diffuse wheezing and a history of chronic obstructive pulmonary disease (COPD), suggest pulmonary hypertension secondary to chronic hypoxic lung disease (cor pulmonale).
Cor pulmonale is a condition of right ventricular failure due to pulmonary hypertension, most often caused by chronic lung diseases like COPD. Clinical findings include signs of right-sided heart failure (JVP elevation, peripheral edema, hepatomegaly) and hypoxemia. Management includes addressing the underlying cause (e.g., COPD exacerbation), optimizing oxygenation, and diuretic therapy to manage volume overload.
Incorrect answers:
A. External compression of the superior vena cava: Superior vena cava syndrome typically causes upper body venous congestion, such as facial swelling, distended neck veins, and cyanosis, without significant lower extremity edema or signs of pulmonary hypertension. These features are absent here.
B. Helicobacter pylori infection with transmural ulceration and peritoneal leaking: Although H. pylori can cause peptic ulcer disease, this does not explain the patient’s respiratory symptoms, hypoxemia, or the findings on chest X-ray. There is no evidence of abdominal pathology such as peritonitis or free air on imaging.
C. Lactic acidosis caused by systemic hypoperfusion: While lactic acidosis can occur due to systemic hypoperfusion (e.g., in sepsis or cardiogenic shock), this patient’s presentation of right-sided heart failure and pulmonary hypertension is more specific for cor pulmonale. There are no clinical or laboratory findings to support lactic acidosis.
E. Widespread hepatocellular necrosis and parenchymal edema: Hepatic injury in cor pulmonale is due to passive congestion, not widespread hepatocellular necrosis. The liver edge palpation is consistent with hepatic congestion secondary to elevated central venous pressures.
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Question 54:
The correct answer is C. This patient presents with symptoms consistent with hyperthyroidism, including weight loss, fatigue, a fine tremor, and tachycardia. Hyperthyroidism results from an overproduction of thyroid hormone, which increases metabolic rate and causes sympathetic nervous system hyperactivity. Heat intolerance, due to the increased basal metabolic rate, is a hallmark feature.
In hyperthyroidism, additional symptoms include palpitations, increased bowel movements, anxiety, and menstrual irregularities. Diagnosis is confirmed with elevated free T4 and suppressed TSH levels.
Incorrect answers:
A. Constipation: This is a symptom of hypothyroidism, not hyperthyroidism.
B. Delayed relaxation reflex: This is also associated with hypothyroidism, often observed as a delayed return of the Achilles tendon reflex.
D. Tenting of the skin: This suggests dehydration or hypovolemia, which is not characteristic of hyperthyroidism.
Question 55:
The correct answer is A. This Kaplan-Meier plot shows that patients who were seizure-free at 2 years after surgery (yellow line) had significantly better long-term seizure control than those with seizures in the first 2 years postoperatively (blue and pink lines). The P-values indicate a statistically significant difference.
Key Findings:
Patients without seizures at 2 years postoperatively maintained a higher seizure-free rate over the next 15 years compared to those who had seizures within 1 or 2 years after surgery. This highlights the importance of early seizure control in predicting long-term outcomes.
Incorrect answers:
B. The Kaplan-Meier curve shows no specific clustering of recurrences in this time frame.
C. This is not supported by the data, which focus on 1- and 2-year subgroups.
D. Statistical significance (P < .05) confirms meaningful conclusions can be drawn.
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Question 56:
The correct answer is B. This 5-year-old boy has progressive difficulty climbing stairs, proximal muscle weakness, and calf pseudohypertrophy, which are classic signs of Duchenne muscular dystrophy (DMD). The diagnosis is supported by markedly elevated serum creatine kinase levels, indicating ongoing muscle damage. DMD is caused by large deletions or mutations in the dystrophin gene, which is critical for stabilizing muscle fiber membranes during contraction. Dystrophin deficiency leads to muscle fiber degeneration and replacement by adipose and connective tissue, causing weakness and pseudohypertrophy.
DMD is an X-linked recessive disorder and typically presents in boys aged 2–5 years with delayed milestones and progressive weakness. Diagnosis involves genetic testing for deletions or mutations in the dystrophin gene. Management focuses on corticosteroids to slow progression and multidisciplinary care to address complications such as cardiomyopathy and respiratory failure.
Incorrect answers:
A. Frameshift insertion in the gene encoding alpha-1 (III) collagen: This is associated with Ehlers-Danlos syndrome, characterized by joint hypermobility and skin fragility, not muscle weakness.
C. Missense mutation in the gene encoding fibrillin 1: This mutation causes Marfan syndrome, presenting with features such as tall stature, aortic root dilation, and ectopia lentis.
D. Splice-site mutation in the gene encoding spectrin: This is associated with hereditary spherocytosis, which presents with hemolytic anemia, jaundice, and splenomegaly.
E. Translocation involving the gene encoding myosin I: Myosin mutations are not associated with DMD or the clinical findings described.
Question 57:
The correct answer is D. This 38-year-old woman presents with confusion, lethargy, severe bradycardia (pulse 32/min), hypotension (74/36 mm Hg), and somnolence. Laboratory findings show elevated liver enzymes, acute kidney injury (creatinine 2.5 mg/dL), and a positive urine toxicology test for opiates. Her presentation is concerning for drug overdose, likely involving a medication that depresses cardiovascular function.
Key features of the clinical presentation:
- Bradycardia and hypotension: Suggest drug-induced cardiovascular depression.
- Somnolence and confusion: Indicate central nervous system (CNS) depression.
- AKI and elevated liver enzymes: Likely due to hypoperfusion from hypotension.
The most likely cause of this presentation is an overdose of a β-blocker (eg, metoprolol, propranolol). β-blockers work by inhibiting β1-adrenergic receptors, leading to decreased heart rate, cardiac output, and blood pressure. Excessive β-blockade can also impair renal and hepatic perfusion, causing acute kidney injury and elevated liver enzymes. CNS depression, such as confusion and lethargy, may occur due to lipophilic β-blockers (eg, propranolol) crossing the blood-brain barrier.
Incorrect answers:
A. Agonism of mu-opioid receptors: Opioid overdose typically causes respiratory depression, pinpoint pupils, and decreased oxygen saturation, which are absent in this patient. Her positive urine toxicology for opiates reflects routine codeine use and is unlikely to explain the bradycardia and hypotension.
B. Inhibition of aldosterone: Causes hyperkalemia and metabolic acidosis, not respiratory depression or CNS effects.
C. Inhibition of angiotensin-converting enzyme (ACE): Associated with cough, hyperkalemia, and angioedema, not the clinical picture described.
E. Inhibition of prostaglandin synthesis: Describes NSAID use. NSAIDs may cause AKI by reducing renal perfusion but do not explain the bradycardia or CNS depression.
F. Inhibition of renal sodium and chloride resorption: Seen with diuretics, leading to electrolyte imbalances, not CNS or respiratory depression.
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Block 4
Question 58:
The correct answer is D. This 64-year-old woman has symptoms of claudication due to peripheral artery disease (PAD), as evidenced by calf pain with exertion, reduced ankle-brachial index (ABI), and decreased pedal pulses. The most appropriate pharmacotherapy is cilostazol, a phosphodiesterase inhibitor. Cilostazol improves symptoms of claudication by inhibiting platelet aggregation and inducing arterial vasodilation, thereby increasing blood flow to ischemic tissues. It is particularly beneficial for patients with lifestyle-limiting claudication who have already optimized medical therapy (e.g., statins and antiplatelets) and lifestyle changes, including smoking cessation and exercise.
PAD is a manifestation of systemic atherosclerosis and is commonly associated with cardiovascular risk factors such as hypertension, diabetes, and hyperlipidemia. Initial management focuses on addressing modifiable risk factors and promoting supervised exercise programs. Cilostazol is added for symptom relief in patients with persistent claudication.
Incorrect answers:
A. Cyclooxygenase: Cyclooxygenase inhibitors, such as aspirin, reduce cardiovascular events but do not address claudication symptoms directly.
B. Factor Xa: Anticoagulation is not indicated in stable PAD unless there is a high risk of thrombosis, such as in acute limb ischemia.
C. Nitric oxide synthase: Nitric oxide donors such as nitrates are used for angina but are not effective for PAD-related claudication.
E. Prostacyclin synthase: Prostacyclin analogs are used for pulmonary hypertension, not for claudication.
Question 59:
The correct answer is B. This 39-year-old woman with a history of Graves’ disease treated with radioactive iodine presents with progressively worsening dyspnea, fatigue, and atrial fibrillation with a rapid ventricular response (RVR). Her clinical presentation is consistent with high-output heart failure secondary to her underlying hyperthyroidism. Echocardiography is the most appropriate next step to confirm the diagnosis and evaluate cardiac function, including structural or functional changes contributing to heart failure.
Pathophysiology: Occurs when cardiac output is elevated but insufficient to meet the metabolic demands of the body. Common causes include hyperthyroidism, anemia, and arteriovenous fistulas. Hyperthyroidism increases basal metabolic rate and oxygen demand, leading to an increase in cardiac output. Chronic exposure to elevated thyroid hormones causes increased heart rate, contractility, and decreased systemic vascular resistance, eventually leading to left ventricular dysfunction. Atrial fibrillation further exacerbates symptoms by reducing cardiac output.
Incorrect answers:
A. CT scan of the chest: Not indicated as there are no findings suggestive of lung pathology (e.g., pulmonary embolism or interstitial lung disease).
C. Perfusion lung scan: Used to evaluate for pulmonary embolism, which is unlikely in the absence of acute symptoms or risk factors.
D. Pulmonary function testing: Not appropriate, as the symptoms are cardiac in origin, not due to obstructive or restrictive lung disease.
E. Ultrasonography of the thyroid: Unnecessary because the patient’s hyperthyroidism is already diagnosed and treated.
Question 60:
The correct answer is A. The study reports no change in bone density in the treatment group and a decrease (2%) in the placebo group, and the decrease in the placebo group is statistically significant (P = 0.01). Bone density is a surrogate marker, but its relationship with fracture risk is complex. A lack of change in density does not necessarily mean the medication effectively prevents fractures, as other factors (e.g., bone quality, microarchitecture) may play a role.
Incorrect answers:
B. The lack of change suggests a confounding variable: Confounding is unlikely with proper randomization in a placebo-controlled trial.
C. The regimen is too complicated: This is speculative and not supported by the data.
D. The Lack of younger women limits long-term evaluation: this does not affect the conclusions within the studied age group (40–60 years).
E. Selection bias: In this study, all participants were selected from general gynecology practices, but this does not create selection bias because both the treatment and placebo groups were drawn from the same pool. Randomization ensures that the groups are comparable in terms of baseline characteristics, so any differences in outcomes can be attributed to the intervention rather than the selection process.
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Question 61:
The correct answer is B. This elderly woman’s progressive confusion and drowsiness over 10 days, along with a visible parietal scalp ecchymosis, strongly suggest chronic subdural hematoma (SDH) as the most likely diagnosis. Chronic SDH often occurs in older adults following minor head trauma, due to increased fragility of bridging veins and brain atrophy, which creates space for slow bleeding.
Symptoms: Gradual onset of altered mental status, drowsiness, or confusion over days to weeks. Neurological deficits may include hemiparesis, headache, or gait disturbances.
Risk Factors: Older age, anticoagulant or antiplatelet use, and minor head trauma.
Pathophysiology: Slow venous bleeding into the subdural space leads to a mass effect, causing symptoms to develop gradually over time.
Diagnosis: A non-contrast head CT is diagnostic and typically reveals a crescent-shaped collection of blood compressing the brain.
Incorrect answers:
A. Drug-drug interaction: There is no evidence of new medications or signs of toxicity from her current medications.
C. Hypothyroidism: While hypothyroidism can cause lethargy or confusion, it does not explain the scalp ecchymosis or sudden onset of symptoms.
D. Major depressive episode: Depression typically presents with chronic low mood or anhedonia, not acute confusion or scalp bruising.
E. Viral encephalitis: This would likely present with fever, headache, seizures, or focal neurological deficits, none of which are present here.
Question 62:
The correct answer is A. This patient reports new-onset anxiety that began after a divorce from her husband of seven years. Adjustment disorder occurs within 3 months of a significant stressor, such as a divorce. It is characterized by emotional or behavioral symptoms that do not meet the criteria for another mental disorder. Anxiety is the predominant symptom here, consistent with adjustment disorder with anxiety.
Incorrect answers:
B. Agoraphobia: This involves avoidance of situations or places due to fear of panic or embarrassment, but this patient’s anxiety appears to occur unpredictably rather than in response to specific situations.
C. Dysthymic disorder: It is characterized by chronic, low-level depression lasting for at least 2 years, but this patient’s main issue is anxiety rather than mood disturbance.
D. Generalized anxiety disorder: GAD involves excessive and uncontrollable worry about various life events, which persists for at least 6 months, but this patient’s anxiety seems more episodic and linked to recent stress.
E. Posttraumatic stress disorder: PTSD involves intrusive memories, flashbacks, or hypervigilance related to trauma, which are not described in this patient’s presentation.
Question 63:
The correct answer is B. The findings in this question describe a young patient who sustained an upper back injury during a football game. Key clinical signs include weakness in the lower extremities, diminished sensation to pain and vibration below the lower chest, absent deep tendon reflexes, and point tenderness over the thoracic spine. These findings strongly indicate spinal cord trauma, likely a contusion at the thoracic level, as a result of the direct impact.
Spinal cord contusions involve bruising of the spinal cord tissue, leading to localized edema, hemorrhage, and potential ischemia. Patients with spinal cord contusions may experience sensory deficits, motor weakness, or complete paralysis, depending on the severity of the injury and the region affected. In this case, the absence of Babinski’s sign and the specific sensory and motor deficits align with a thoracic spinal cord injury rather than a more diffuse condition like syrinx or cord hemisection. Immediate evaluation with imaging, such as MRI, is critical to confirm the diagnosis and guide management.
Incorrect answers:
A. Anterior spinal artery territory ischemia: This condition typically results in bilateral motor weakness and pain/temperature sensory loss below the level of the lesion, sparing vibration and proprioception. This patient retains vibration sense in some areas, making this less likely.
C. Lateral T7 disc herniation with nerve root compression: This would cause radicular pain and unilateral motor and sensory symptoms rather than bilateral findings.
D. Thoracic cord hemisection: Brown-Séquard syndrome involves ipsilateral motor and proprioceptive loss with contralateral pain and temperature sensation loss. This pattern is inconsistent with this patient’s symptoms.
E. Traumatic syrinx: Syringomyelia presents with loss of pain and temperature sensation in a cape-like distribution, which does not match the presentation here.
Question 64:
The correct answer is A. This 78-year-old woman with advanced renal failure has a documented “do not attempt resuscitation” (DNAR) order and declined hemodialysis despite understanding its potential consequences. The patient’s previously expressed wishes, documented in her medical record and communicated through her surrogate decision-maker, should guide care. Continuing current management aligns with her decision to forgo dialysis, respecting her autonomy.
In patients with a DNAR order, medical care focuses on comfort and quality of life rather than aggressive, life-prolonging interventions. Shared decision-making is critical, involving the patient (or surrogate) and the care team to ensure treatment aligns with the patient’s values. Hemodialysis, while life-saving for many, would not align with this patient’s expressed goals of care.
Incorrect answers:
B. Initiate hemodialysis and change the code status: This violates the patient’s autonomy and previously expressed wishes. A DNAR order does not mean withholding care, but forcing dialysis contradicts her documented decision.
C. Initiate hemodialysis but keep the DNAR status: Even if the DNAR is maintained, initiating dialysis would still disregard the patient’s refusal of this intervention.
D. Obtain consent to initiate all medical interventions: This undermines the patient’s autonomy and is unnecessary given her previously documented care preferences.
Question 65:
The correct answer is D. This 75-year-old woman presents with a syncopal episode triggered by standing, with associated orthostatic hypotension (a significant drop in blood pressure upon standing). She has no history of tonic-clonic movements or neurological deficits, and her CT scan is normal, ruling out structural brain causes. Orthostatic vital sign measurements reveal a drop in systolic blood pressure and a compensatory increase in heart rate, consistent with hypovolemia or autonomic dysfunction. Telemetry observation is crucial for monitoring cardiac rhythm and detecting any arrhythmias, a common cause of syncope.
Orthostatic hypotension: Defined as a drop in systolic BP ≥20 mm Hg or diastolic BP ≥10 mm Hg within 3 minutes of standing. Common in elderly patients and those on antihypertensive medications like lisinopril.
Management: Address underlying causes (e.g., adjust medications, ensure adequate hydration).
Telemetry observation for rhythm monitoring.
Incorrect answers:
A. Electroencephalography: Used to diagnose seizures, but there is no evidence of a seizure (no tonic-clonic movements or postictal confusion).
B. Outpatient ambulatory ECG monitoring: Less suitable as the patient is symptomatic and requires immediate monitoring.
C. Outpatient echocardiography: Useful for structural heart disease but not first-line for unexplained syncope without arrhythmias.
E. Tilt test – Reserved for unexplained syncope after initial evaluation is inconclusive
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Question 66:
The correct answer is A. The proposed study examines a potential association between dental x-rays and thyroid cancer. The Institutional Review Board (IRB) plays a critical role in ensuring the ethical conduct of research, particularly when human participants are involved. In this scenario, the study design includes sufficient safeguards: informed consent and federal funding requirements, which necessitate ethical oversight and adherence to regulations.
The IRB’s concern regarding “potential liability for the institution if an association is found” is not a sufficient reason to reject or modify the study. Ethical and scientific reviews must be conducted independently of liability concerns. Moreover, including liability-related language in the consent form would be inappropriate and could introduce unnecessary fear or bias in participants.
Incorrect answers:
B. Do not approve the study: This option is not appropriate because the study is ethically sound and scientifically relevant, and the IRB’s role is to ensure safety and ethics, not to preemptively limit research based on potential results.
C. Require language in the informed consent document advising participants of the right to sue should a positive association between dental x-rays and thyroid cancer be found: This is inappropriate because potential legal outcomes are not typically included in informed consent unless there is a clear risk of harm or direct injury, which is not the case here.
D. Require language in the informed consent document releasing the institution from liability: This is not necessary because such a release is unlikely to be enforceable and does not address the core ethical concern of informed consent, which is to provide participants with information about the study’s purpose, risks, and benefits, not institutional liability.
Question 67:
The correct answer is E. This 15-year-old boy presents with a large, fixed, tender chest wall mass that developed over three months. He denies systemic symptoms like fever, weight loss, or night sweats. The physical examination reveals no abnormalities aside from the palpable mass, and there is no history of trauma or infection. These findings point to a malignancy, particularly a primary bone or soft tissue tumor. Given his age and the location of the mass, the most likely diagnosis is Ewing sarcoma, a highly aggressive tumor often found in adolescents.
Ewing sarcoma is a small, round, blue cell tumor that commonly arises in the diaphysis of long bones, pelvis, or chest wall (e.g., the ribs). On biopsy, it characteristically shows poorly differentiated anaplastic spindle cells. The clinical presentation includes pain, swelling, and sometimes systemic symptoms like fever or fatigue. Imaging often reveals a destructive bone lesion with a characteristic “onion-skin” periosteal reaction. Definitive diagnosis requires biopsy and genetic testing. Treatment involves a combination of chemotherapy, surgery, and/or radiation therapy, as these tumors are highly aggressive but sensitive to therapy.
Incorrect answers:
A. Acid-fast bacilli: Suggests tuberculosis, but this presentation lacks systemic symptoms such as fever or night sweats.
B. Gram-positive cocci: Indicates infection (e.g., abscess), but the patient lacks signs of infection (fever, leukocytosis).
C. Squamous cells and keratin: Indicates squamous cell carcinoma, rare in this age group and not typical for a chest wall mass.
D. Syncytiotrophoblasts and cytotrophoblasts: Seen in choriocarcinoma, a germ cell tumor associated with elevated beta-hCG levels, which is irrelevant in this case.
Question 68:
The correct answer is B. Esophagus. This 66-year-old woman presents with a 3-day history of progressively worsening pain with swallowing solids and liquids (odynophagia). She has no nausea, vomiting, or appetite loss. A key detail in her history is the use of alendronate for osteoporosis. Bisphosphonates, especially alendronate, are well known to cause pill-induced esophagitis when tablets lodge in the esophagus, particularly if taken without adequate water or if the patient lies down shortly after ingestion. This results in direct mucosal injury and ulceration of the esophagus. The acute onset of odynophagia and lack of systemic symptoms strongly suggest localized esophageal mucosal damage. Endoscopy would most likely reveal ulceration in the esophagus, commonly in the mid-esophagus where pills tend to lodge.
Incorrect answers:
A. Duodenum: Duodenal ulcers typically present with epigastric abdominal pain, often relieved by food. They do not cause isolated pain with swallowing (odynophagia), which localizes pathology to the esophagus.
C. Gastric cardia: Ulceration in the gastric cardia would present with epigastric discomfort, nausea, or dyspepsia rather than acute pain triggered by swallowing both solids and liquids.
D. Gastric fundus: Fundal ulcers are associated with peptic ulcer disease and cause epigastric pain, not odynophagia. There is no evidence of melena, hematemesis, or chronic dyspeptic symptoms.
E. Pylorus: Pyloric pathology typically presents with symptoms of gastric outlet obstruction (eg, early satiety, vomiting) or peptic ulcer disease, not acute painful swallowing.
Question 69:
The correct answer is C. This 72-year-old woman with a long history of smoking presents with progressive dyspnea, a prolonged expiratory phase, and obstructive spirometry findings (low FEV1/FVC ratio with minimal reversibility). The chest X-ray shows hyperinflated lungs with flattened diaphragms, which are classic for emphysema, a subtype of chronic obstructive pulmonary disease (COPD).
Emphysema is characterized by the destruction of alveolar walls, which leads to the permanent enlargement of air spaces distal to the terminal bronchioles. This process decreases the surface area for gas exchange and causes airway collapse during exhalation, limiting airflow. The condition is strongly associated with smoking, which induces oxidative stress and inflammatory damage to the lungs.
Incorrect answers:
A. Bacterial colonization of large- and medium-sized airways is more consistent with chronic bronchitis, which presents with a productive cough and frequent infections.
B. Bronchial constriction in response to environmental allergens describes asthma, which typically presents earlier in life with intermittent, fully reversible airflow obstruction.
D. Diffuse patchy interstitial inflammation and fibrosis: Interstitial lung disease causes restrictive patterns on spirometry, not obstruction.
E. Eosinophilic infiltration of the pulmonary interstitium: Eosinophilic lung diseases often present with restrictive patterns and peripheral eosinophilia, not obstructive findings.
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Question 70:
The correct answer is D. This study involves surveying a random sample of 5,000 physicians to assess their prescribing patterns for β-blockers in heart failure. It collects data on physician behavior, age, location, and type of practice at a single point in time. Such a design is characteristic of a cross-sectional study, which evaluates the prevalence of exposure or behavior and its associations with other variables.
Cross-sectional studies are observational in nature and provide a snapshot of the population at a given time. They are useful for identifying trends, generating hypotheses, and determining the burden of a condition or practice. However, they cannot establish causation due to the lack of temporal data.
Incorrect answers:
A. Case-control study: Compares individuals with and without a condition retrospectively to identify exposures. The study in question does not have cases and controls.
B. Case series: Describes a series of patients without a comparison group or random sampling. This study involves a large random sample with statistical stratification.
C. Clinical trial: Involves randomization and intervention, absent in this observational design.
E. Prospective cohort study: Follows individuals over time to assess future outcomes. The study in question evaluates behavior at one point in time.
F. Retrospective cohort study: Examines past exposures and their relationship to outcomes. In cohort studies, the subjects are categorized based on their exposure.
Question 71:
The correct answer is C. This 79-year-old man presents with acute-onset dizziness, instability, and horizontal nystagmus triggered by head movements. These findings are consistent with labyrinthitis, a condition caused by inflammation of the inner ear structures, specifically the labyrinth, which houses the vestibular system responsible for balance. Labyrinthitis is often a sequela of a viral infection and results in both vertigo and hearing loss.
Etiology: Typically follows a viral upper respiratory infection, but it can also occur due to bacterial infections, head trauma, or ototoxic medications. In this case, the patient’s history and symptoms strongly suggest a viral etiology.
Symptoms: Sudden-onset vertigo, often described as a sensation of spinning that worsens with head movement. Nausea and vomiting, secondary to the vertigo. Imbalance and unsteady gait.
Hearing loss: Present in many cases, though not noted here (likely mild in this case). Tinnitus may also occur in some cases.
Diagnosis: Clinical, based on history and physical exam findings, particularly nystagmus that is positional and suppressed by visual fixation. Vestibular testing or imaging (e.g., MRI) is only needed if central causes (e.g., stroke) are suspected.
Management: Vestibular suppressants such as meclizine or benzodiazepines (e.g., lorazepam) to alleviate vertigo. Antiemetics for nausea and vomiting.
Differentiation from Other Causes: Labyrinthitis is a peripheral vertigo condition, as evidenced by horizontal nystagmus that suppresses with visual fixation. Central causes (e.g., stroke) would present with vertical or direction-changing nystagmus and additional neurological signs.
Incorrect answers:
A. Arrhythmias cause syncope or near-syncope, not vertigo or positional symptoms.
B. Although alcohol can damage the cerebellum over time, this patient has no history of heavy alcohol use or cerebellar findings (e.g., dysmetria, ataxia, or intention tremor).
D. This condition presents as dizziness or lightheadedness upon standing, not positional vertigo. The patient’s blood pressure is stable, and symptoms are unrelated to standing or sitting.
E. Central vertigo due to posterior circulation stroke would present with additional findings, such as focal neurological deficits (e.g., weakness, dysarthria) or vertical nystagmus. The patient’s examination is consistent with a peripheral cause.
Question 72:
The correct answer is B. This 73-year-old man presents with a necrotic ulcer on his right foot after a prolonged hospitalization for pneumonia, sepsis, and respiratory failure. He is frail, noncommunicative, and confined to bed, all of which suggest prolonged immobility as the primary cause of his condition. Prolonged immobility leads to pressure-induced ischemia and subsequent necrosis, commonly seen in bedridden or debilitated patients. This results in pressure ulcers, typically over bony prominences, but they can also occur in areas subjected to sustained pressure, such as the heels.
Pressure ulcers develop when sustained pressure exceeds capillary perfusion pressure, leading to localized ischemia and tissue necrosis. This process is exacerbated by factors such as malnutrition, advanced age, incontinence, and impaired mobility. The patient’s history of hospitalization and frailty significantly increases his risk. Management includes offloading pressure from the affected area, ensuring adequate nutrition, wound care, and treating any secondary infections. Prevention is crucial and involves frequent repositioning, use of pressure-relieving devices, and optimizing overall health.
Incorrect answers:
A. Infection with methicillin-resistant Staphylococcus aureus: Although MRSA can cause wound infections, there is no mention of erythema, purulent discharge, or signs of systemic infection, suggesting infection is not the primary etiology here.
C. Pyoderma gangrenosum: This condition presents as rapidly progressing, painful ulcers with undermined borders, typically associated with autoimmune diseases (e.g., inflammatory bowel disease or rheumatoid arthritis), which are not noted in this patient.
D. Systemic atheroemboli: Atheroembolic disease typically presents with signs of ischemia in multiple sites (e.g., blue toe syndrome, livedo reticularis), rather than a single localized necrotic ulcer.
E. Venous stasis secondary to valvular incompetence: Venous stasis ulcers are typically located on the medial malleolus and associated with venous insufficiency symptoms (e.g., edema, hyperpigmentation), not the heel.
Question 73:
The correct answer is A. This 8-year-old girl presents with a generalized tonic-clonic seizure followed by asystole, global hypokinesis, and severe left ventricular dysfunction (EF 20%) on echocardiography. Despite intensive care, the patient dies, and autopsy reveals an acute myocardial infarction. The findings are suggestive of arrhythmogenic cardiac conduction abnormalities leading to sudden cardiac arrest and secondary hypoxic injury to the myocardium.
Cardiac conduction abnormalities, such as congenital long QT syndrome or catecholaminergic polymorphic ventricular tachycardia (CPVT), are common causes of cardiac arrest in young patients without coronary artery disease.
Long QT syndrome: Prolonged repolarization predisposes to torsades de pointes, resulting in syncope or sudden cardiac death.
CPVT: Triggered by adrenergic stimuli (e.g., exercise, stress) leading to ventricular tachyarrhythmias.
Role of Arrhythmias: Arrhythmias cause transient asystole, reduced cardiac output, and hypoperfusion, leading to myocardial ischemia, hypokinesis, and eventual pump failure.
Incorrect answers:
B. Coronary artery plaque rupture: Unlikely in a child with no atherosclerotic risk factors; autopsy findings would also show evidence of atherosclerosis, which is absent.
C. Increased pulmonary vascular resistance: May lead to right-sided heart failure, but there is no evidence of pulmonary hypertension or right heart strain here.
D. Systolic prolapse of mitral valve: Seen in mitral valve prolapse but would not account for the severity of global hypokinesis or asystole.
E. Thickened left ventricular wall and contractile dysfunction: Suggestive of hypertrophic cardiomyopathy, but this patient’s echocardiography findings do not show hypertrophy, and no such findings were noted at autopsy.
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Question 74:
The correct answer is C. This 37-year-old woman presents with acute, severe right-sided abdominal pain radiating to the pelvic region, associated with nausea. The physical exam reveals tenderness over the right flank and costovertebral angle. The presence of trace hematuria (occult blood in urine) and normal renal function, along with these findings, strongly suggests ureteral obstruction, most likely due to nephrolithiasis (kidney stones). The next best step in evaluation is a helical (spiral) CT scan of the abdomen and pelvis without contrast, which is highly sensitive and specific for detecting ureteral stones.
Initial symptom control:
- Analgesics (e.g., NSAIDs or opioids for pain).
- Antiemetics for nausea.
- IV fluids to maintain hydration.
Imaging:
- Helical (spiral) CT scan without contrast is the gold standard for detecting ureteral stones.
- Ultrasonography may be used in pregnant patients or where radiation exposure is a concern.
High Yield:
- If complications are present (e.g., infection, complete obstruction, AKI), inpatient admission and urgent urology consultation are required.
- For stones ≤10 mm without complications, outpatient management with pain control, hydration, and alpha blockers (if 5mm< stone <10mm) can be initiated.
Incorrect answers:
A. Cystoscopy: Used for evaluation of bladder pathology or hematuria, but not appropriate for initial imaging in suspected nephrolithiasis.
B. Exploratory laparotomy: Invasive and not indicated unless there are signs of surgical emergencies (e.g., perforation, bowel ischemia).
D. X-ray of the kidney, ureter, and bladder (KUB): Limited sensitivity and specificity for detecting kidney stones, especially radiolucent stones (e.g., uric acid).
E. No further testing is indicated at this time: Incorrect; imaging is necessary to confirm the diagnosis and guide management.
Question 75:
The correct answer is C. This postmenopausal woman presents with abnormal vaginal bleeding, which is concerning for endometrial hyperplasia or endometrial cancer. The first-line diagnostic step in evaluating postmenopausal bleeding is endometrial biopsy.
Endometrial biopsy is indicated in women ≥ 45 years old with postmenopausal bleeding, especially if they have risk factors for endometrial hyperplasia or cancer. These risk factors include obesity, diabetes mellitus, and unopposed estrogen exposure. Alternatively, a transvaginal ultrasound can be performed first, and if the endometrial thickness is >4 mm, an endometrial biopsy is warranted.
Incorrect answers:
A. Complete blood count: A CBC is not indicated unless there are signs of anemia or infection.
B. CT scan of the pelvis: A CT scan is not the first step in evaluating abnormal uterine bleeding; ultrasound is typically preferred.
D. Hysterosalpingography: This test evaluates tubal patency and is not indicated for postmenopausal bleeding.
E. CA 125: CA 125 is used primarily for ovarian cancer monitoring. It is not used for diagnosing endometrial cancer.
Question 76:
The correct answer is C. This 2-year-old girl is diagnosed with lymphadenitis, and her father is concerned due to a family history of cancer. The most appropriate response demonstrates empathy while exploring the father’s specific concerns. Open-ended questions like “Tell me what your greatest concerns are” encourage dialogue and address the underlying fear of malignancy.
Effective Communication in Pediatric Cases:
- Show empathy and acknowledge the parent’s concerns.
- Use open-ended questions to gather more information about fears or expectations.
- Reassure the parent with evidence-based explanations if appropriate.
Incorrect answers:
A. Dismissive tone may alienate the parent and prevent open communication.
B. Dismisses concerns without exploring them fully.
D. Overly reassuring and ignores the family’s fears.
E. Although this seeks clarification, it can come across as defensive or challenging rather than empathetic.
Question 77:
The correct answer is B. This 88-year-old woman with long-standing dementia and altered mental status is unable to participate in her own medical decision-making. Her agitated behavior and inability to communicate coherently prevent an effective physical examination. Contacting her healthcare proxy ensures that decisions are made in accordance with her best interests and previously expressed preferences.
Healthcare proxies are designated to make medical decisions when a patient lacks capacity. In such cases, it is essential to involve the proxy to ensure appropriate care while respecting the patient’s autonomy and prior directives. This approach avoids unnecessary interventions while addressing the underlying issue (e.g., rectal bleeding).
Incorrect answers:
A. Administer lorazepam and proceed with the exam: Sedating the patient may allow examination but does not address the need for a proxy to guide care decisions.
C. Place the patient in restraints: This approach is unnecessarily restrictive, escalates distress, and could worsen agitation.
D. Schedule outpatient sigmoidoscopy and discharge: The patient’s altered mental status requires inpatient evaluation, and sigmoidoscopy is not the initial step in managing rectal bleeding in an unstable or uncooperative patient.
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Block 5
Question 78:
The correct answer is B. This 64-year-old woman has chronic constipation with failure of fiber and no alarm features; rectal examination shows decreased sphincter tone and soft stool in the vault, suggesting a possible pelvic floor or anorectal dysfunction. Anorectal manometry (often with balloon-expulsion testing) is the appropriate next diagnostic step to assess sphincter function and defecatory coordination and to guide therapy.
Incorrect answers:
A. Addition of bisacodyl to the medication regimen: A stimulant laxative may help stool frequency, but physiologic testing is indicated first given abnormal rectal exam findings.
C. Colonoscopy: Not indicated now—she had a normal colonoscopy 5 years ago and has no alarm symptoms (weight loss, bleeding, iron deficiency).
D. Discontinuation of lisinopril: Lisinopril is not a common cause of chronic constipation and stopping it is unnecessary.
E. Recommendation to maintain a daily bowel movement journal for 1 month: Useful for assessment but insufficient alone; objective anorectal testing is warranted to define the underlying dysfunction.
Question 79:
The correct answer is F. This patient with severe bradycardia (pulse 30/min), hypotension (75/35 mm Hg), and symptoms of poor perfusion (lightheadedness, diaphoresis, altered mentation, cool skin) has symptomatic bradyarrhythmia, most likely due to sinus node dysfunction or high-grade AV block from ischemic cardiomyopathy and β-blocker use. The immediate management is transcutaneous pacing, which provides temporary cardiac support until a definitive pacemaker can be placed. If unavailable, IV atropine may be attempted, followed by dopamine or epinephrine infusion as a bridge to pacing.
Incorrect answers:
A. Adenosine therapy: Used for paroxysmal supraventricular tachycardia, not for bradycardia. Would worsen this patient’s rhythm.
B. Continuous infusion of dobutamine: Increases contractility but does not correct severe bradycardia; inappropriate as first step.
C. Continuous infusion of epinephrine: Can be used as a bridge if pacing is unavailable, but pacing is preferred in unstable bradycardia.
D. Defibrillation: Used for pulseless ventricular tachycardia or fibrillation, not for organized bradycardia with pulse.
E. Intubation and mechanical ventilation: Airway may later be needed, but the immediate cause of shock is bradycardia, which must be corrected first.
Question 80:
The correct answer is A. A 14-year-old boy exhibits odd behavior, then becomes somnolent and difficult to arouse. He has small pupils (2 mm) that are minimally reactive, decreased bowel sounds, and generalized lethargy. There is no mention of trauma or underlying medical problems. Over-the-counter cough suppressant abuse (dextromethorphan) can cause significant CNS depression and opioid-like effects at high doses (it acts on NMDA receptors and can also have mild mu-opioid receptor activity). Adolescents may misuse dextromethorphan for its hallucinogenic or sedative properties.
Key features of dextromethorphan abuse
- Altered mental status (euphoria, hallucinations, or sedation)
- Potential respiratory depression and sedation in large doses
- Can cause mild miosis (though pupil effects vary)
Incorrect answers:
B. Diazepam: A benzodiazepine causing sedation, but typically also leads to respiratory depression with normal or sometimes slightly larger pupils, not typically pinpoint.
C. Diphenhydramine: Can cause sedation and anticholinergic effects (usually dilated pupils and decreased bowel sounds), but the small pupils do not fit classic anticholinergic toxidrome.
D. Methylphenidate: A stimulant causing hyperactivity, dilated pupils, tachycardia—not sedation with small pupils.
E. Phenylephrine: A sympathomimetic that causes mydriasis (pupil dilation) and increased blood pressure, not miosis and sedation.
Question 81:
The correct answer is C. This 65-year-old woman is being discharged after surgical repair of a hip fracture and will continue insulin therapy at home. The most appropriate role for home health services is to assist the patient in strengthening her lower-extremity muscles. Strengthening exercises improve ambulation with a walker, enhance balance, and promote recovery of independence following major lower-limb surgery. Focused physical therapy also prevents deconditioning and reduces the risk of subsequent falls and complications such as thromboembolism and muscle atrophy.
Incorrect answers:
A. Administer daily insulin: The patient is alert, cognitively intact, and capable of self-administering insulin. Routine home nursing visits solely for insulin administration are not warranted.
B. Assist the patient in building her upper-body strength: Although upper-body strength may aid in using a walker, lower-extremity rehabilitation is the main focus following hip replacement to restore gait and mobility.
D. Ensure that the patient follows the diabetic diet prescribed for her: Adherence to diet can be reinforced during outpatient follow-up or by a dietitian. It is not the primary purpose of post–hip-repair home services.
E. Measure the patient’s blood glucose concentration daily: The patient can self-monitor her glucose levels. Home nursing visits are unnecessary for routine glucose checks in stable diabetic patients.
Question 82:
The correct answer is C. A 27-year-old woman underwent resection of a right parietal lobe astrocytoma. Now, she has mild left-sided weakness, some left lower-extremity spasticity, and extinction to double simultaneous stimulation (indicative of left-sided neglect or inattention). Although she is alert, oriented, and otherwise cognitively intact, right parietal lesions often impair visual spatial processing and can lead to hemineglect (inattention to the contralateral side). She works as a graphic designer, so evaluating how this neglect or inattention affects her visual spatial abilities is crucial for safely returning to work.
Incorrect answers:
A. Capacity to articulate ideas and thoughts: Her speech is fluent, so articulation and language function are not the main concerns.
B. Degree of control over her left hand: She has mild weakness but is 4/5 in strength. The bigger issue is whether she perceives and properly attends to the left side.
D. Overall ability to ambulate: She has mild circumduction but no ataxia. Mobility is not the most critical area of concern for returning to her work as a graphic designer. The primary issue is visual spatial neglect.
Question 83:
The correct answer is E. This patient presents with fatigue, easy bruising, and pancytopenia (WBC 1,200/mm³, platelets 43,000/mm³, hemoglobin 9.3 g/dL)—findings consistent with agranulocytosis due to methimazole toxicity. Methimazole and propylthiouracil (PTU) can cause life-threatening agranulocytosis, most commonly within the first few months of therapy, though it can occur later as well. The mechanism involves immune-mediated destruction or direct bone marrow suppression.
Incorrect answers:
A. Aspirin: Can cause thrombocytopenia (via platelet dysfunction) but not pancytopenia.
B. Atorvastatin: May cause mild transaminitis or myopathy, not cytopenias.
C. Carvedilol: Beta-blockers have no hematologic toxicity.
D. Lisinopril: Causes dry cough and angioedema.
Question 84:
The correct answer is B. This woman has amyotrophic lateral sclerosis (ALS) — progressive involvement of both upper and lower motor neurons, shown by spasticity (hyperreflexia), muscle weakness, and fasciculations. The presence of bulbar symptoms (dysarthria, dysphagia, tongue fasciculations) indicates degeneration of the medullary motor nuclei, which control swallowing and speech.
Bulbar involvement is the most important negative prognostic factor, as it leads to aspiration pneumonia and respiratory failure, the main causes of death in ALS.
Incorrect answers:
A. Age: ALS commonly begins between ages 40–60; age of onset has little direct effect on survival.
C. Cervical fusion operation: A prior spinal surgery is unrelated to the neurodegenerative process.
D. Fasciculations: These indicate lower motor neuron disease but are not independently associated with worse prognosis.
E. Gender: ALS affects men slightly more than women, but survival is determined by disease pattern, not sex.
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Question 85:
The correct answer is C. A 36-year-old woman with newly diagnosed Graves’ disease was started on methimazole 3 weeks ago and initially improved. She now presents with acute-onset high fever (40.0°C/104.0°F), sore throat, and markedly low white blood cell (WBC) count (3300/mm³) with profoundly decreased neutrophils. This clinical picture is highly suggestive of methimazole-induced agranulocytosis, a known but relatively rare side effect of thionamides (methimazole, propylthiouracil). Agranulocytosis leads to increased susceptibility to infection, and her fever and pharyngeal erythema raise concern for a serious bacterial process.
This usually occurs within the first few months of therapy. Can present with fever, sore throat, oral ulcers, or other infection sites. Management involves immediate discontinuation of methimazole and prompt evaluation for infection. Given her high fever and likely or impending infection in the setting of severe neutropenia, the most appropriate next step is to start broad-spectrum IV antibiotics. Cefepime is an antipseudomonal, fourth-generation cephalosporin that provides good gram-negative and gram-positive coverage.
Incorrect answers:
A. Antinuclear antibody (ANA) test: ANA testing would be considered for autoimmune disorders (eg, lupus). This does not address her acute infection risk from agranulocytosis.
B. Bone marrow aspiration and biopsy: While it can confirm drug-induced agranulocytosis, it is not the most immediate next step before stabilizing and covering for possible severe infection.
D. Filgrastim therapy: G-CSF can help expedite neutrophil recovery but is generally adjunctive to antibiotics, not a substitute for urgent antibiotic initiation.
E. HIV antibody test: Although HIV can cause low WBC counts, nothing else in the history specifically suggests HIV. This test does not address the immediate concern of infection risk.
F. Propylthiouracil therapy: Switching from methimazole to PTU may be an option later for ongoing Graves management, but PTU can also cause agranulocytosis. The top priority now is treating the likely infection.
Question 86:
The correct answer is D. This premature neonate with respiratory distress syndrome (RDS) who now develops sudden hypotension, cyanosis, and poor perfusion despite bilateral breath sounds has cardiac tamponade from central line (umbilical venous catheter) malposition. The chest x-ray shows the catheter tip projecting over the cardiac silhouette, consistent with entry into the right atrium or pericardial space, leading to fluid accumulation and impaired venous return.
Immediate management:
Perform pericardiocentesis to relieve pressure on the heart, followed by catheter removal and correct repositioning under ultrasound or fluoroscopic guidance.
Incorrect answers:
A. Insertion of a central venous catheter: Already present — incorrect.
B. Median sternotomy: Surgical exposure, not for acute tamponade relief.
C. PEEP reduction to 6 cm H₂O: Used for barotrauma-related hypotension (e.g., tension pneumothorax), but here the problem is pericardial tamponade.
E. Placement of a left chest tube: For pneumothorax — not indicated since breath sounds are equal.
Question 87:
The correct answer is C. According to USPSTF/ACOG guidelines, cervical cancer screening should follow these intervals:
- Start at age 21 → Cytology (Pap test) alone every 3 years.
- Ages 30–65 → Either
○ Cytology alone every 3 years, or
○ High-risk HPV testing alone every 5 years, or
○ Co-testing (Pap + HPV) every 5 years. - Stop after age 65 if the patient had adequate prior negative screening and no history of CIN2+ or cervical cancer.
This 38-year-old had negative cytology and HPV testing → Next screening in 5 years.
Incorrect answers:
A. At the time of menopause: Menopause does not change screening intervals.
B. In 1 year: Too frequent; unnecessary with a negative co-test.
D. Only if she gets pregnant: Pregnancy is not a screening indication.
E. No further cytology: Discontinue only after 65 with adequate prior screening.
Question 88:
The correct answer is E. This 44-year-old woman with chronic myofascial pain syndrome reports an allergy to local anesthetics after developing severe itching and redness at the injection site 48 hours following a previous trigger point injection. The most appropriate next step is referral to an allergist to determine the specific allergen involved. This evaluation will help avoid future adverse reactions and guide the selection of safe anesthetic options.
Etiology:
- True allergies to local anesthetics are rare and can be due to preservatives or the anesthetic itself (amide vs. ester class).
- Symptoms often include localized or systemic itching, rash, or anaphylaxis.
Management:
- Allergy testing (e.g., skin or patch testing) is necessary to identify the causative agent.
- Once identified, alternative local anesthetics or non-allergenic options can be used.
Trigger point injections:
- Commonly used for myofascial pain to relieve muscle tension and improve function.
- Alternatives to local anesthetics, such as saline, may be used if an allergy is confirmed.
Incorrect answers:
A. Phenol is not a standard anesthetic for trigger point injections and carries a risk of neurotoxicity.
B. Without allergy testing, using a different local anesthetic carries a risk of repeated allergic reactions.
C. Tetracaine is an ester anesthetic, and switching anesthetic classes without testing does not guarantee safety.
D. Pretreatment with an antihistamine does not prevent true allergic reactions, especially if the patient has a confirmed allergy to local anesthetics.
Question 89:
The correct answer is E. The correct answer is E. This 62-year-old man has a history of stage III colon cancer treated with surgery and adjuvant chemotherapy. The detection of a new pulmonary nodule with irregular borders and increased uptake on PET/CT suggests metastatic disease. Surgical resection of the nodule is appropriate because:
- There is no evidence of other metastatic disease.
- Resectig solitary lung metastases in colorectal cancer can improve survival.
Incorrect answers:
A. Bronchoscopy: Not indicated unless the nodule is centrally located or requires biopsy confirmation.
B. Chemotherapy: Used for widespread or unresectable disease but not first-line for isolated metastases.
C. Discussion of palliative care: Premature, as the disease is potentially curable.
D. Radiation therapy: Rarely used for colorectal cancer metastases unless resection is not possible.
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Question 90:
The correct answer is C. A 38-year-old man with type 1 diabetes mellitus and hemochromatosis is stable on therapy. Hemochromatosis predisposes to infections with iron-dependent organisms, including Vibrio vulnificus, which is found in raw oysters. Patients with chronic liver disease or hemochromatosis are at very high risk for Vibrio sepsis, which has a high mortality rate.
Hemochromatosis leads to excess iron storage, which fuels bacterial growth. Vibrio vulnificus is an iron-dependent organism found in raw seafood, especially oysters. Infections can cause sepsis and necrotizing fasciitis, particularly in immunocompromised individuals. Management includes dietary modifications (avoiding raw seafood) and iron reduction therapies like phlebotomy.
Incorrect answers:
A. Bean sprouts: Although raw sprouts can harbor bacteria (eg, Salmonella, E coli), the key lethal risk in hemochromatosis is Vibrio vulnificus from oysters.
B. Berries: Unwashed berries can carry pathogens, but they are not classically associated with life-threatening infections in hemochromatosis
D. Undercooked eggs: Risk of Salmonella exists, but the mortality risk is far lower than Vibrio sepsis in hemochromatosis patients.
Question 91:
The correct answer is B. This patient presents with acute scrotal pain and tenderness of the left testicle, most likely due to testicular torsion. Immediate intervention (e.g., manual detorsion or surgical orchiopexy) is critical to restore blood flow and prevent testicular necrosis. If promptly managed, fertility is generally preserved.
Pathophysiology: Twisting of the spermatic cord compromises blood flow to the testis, causing ischemia.
Management: Emergency surgical detorsion and orchiopexy to salvage the testicle. The contralateral testis is also secured to prevent future torsion.
Incorrect answers:
A. Unlikely if managed promptly.
C. Conservative management is inappropriate as surgical intervention is required.
D. No need for further evaluation.
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Question 92:
The correct answer is B. This 62-year-old male patient is experiencing significant postoperative pain (9/10) following total knee arthroplasty. His obesity (BMI 39 kg/m²) and episodes of apnea in response to opioid administration indicate a high risk for opioid-induced respiratory depression. A femoral nerve block with bupivacaine is the most appropriate next step for pain management. This regional anesthetic technique effectively controls pain while minimizing systemic side effects, including respiratory depression.
Mechanism: Local anesthetic is injected around the femoral nerve, providing targeted pain relief for the anterior knee and thigh. Reduces the need for systemic opioids, thereby lowering the risk of opioid-related adverse effects.
Indications:
Postoperative pain following knee surgery.
Patients at high risk for opioid side effects, such as those with obesity, obstructive sleep apnea, or respiratory depression.
Advantages:
Effective localized pain relief.
Reduced sedation and respiratory compromise.
Incorrect answers:
A. Administration of oxygen via high-flow nasal cannula: Oxygen therapy does not address the underlying cause of this patient’s pain and risk of opioid-induced respiratory depression.
C. Chest wall impedance monitoring: While useful for detecting apnea, this does not manage the patient’s pain or reduce opioid-related risks.
D. Continuous pulse oximetry: Provides monitoring but does not prevent respiratory depression or address pain.
E. Hydromorphone via patient-controlled analgesia (PCA): Hydromorphone increases the risk of respiratory depression and is contraindicated in this patient given his history of opioid sensitivity and apnea.
Question 93:
The correct answer is B. This 32-year-old woman presents with liver injury due to acetaminophen toxicity, compounded by chronic alcohol use. Alcohol upregulates cytochrome P450 enzymes, increasing the conversion of acetaminophen into its toxic metabolite, NAPQI. Her lab findings (elevated AST/ALT and metabolic acidosis) are consistent with acute liver injury. Alcohol is the strongest predictor of poor prognosis in this setting.
Acetaminophen is metabolized in the liver; a small portion is converted to NAPQI, a hepatotoxic metabolite. Alcohol increases NAPQI production by inducing CYP2E1, exacerbating liver injury even with moderate acetaminophen doses. Symptoms include nausea, vomiting, and right upper quadrant pain.
Management:
- Early administration of N-acetylcysteine (NAC) to replenish glutathione and detoxify NAPQI.
- Supportive care, including monitoring for liver failure.
Incorrect answers:
A. Chronic hepatitis B infection: This patient does not have chronic hepatitis B (HBsAg-negative).
C. Fluoxetine therapy: SSRIs are not associated with acetaminophen metabolism or prognosis.
D. Type 1 diabetes mellitus: It does not influence acetaminophen toxicity prognosis.
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Question 94:
The correct answer is E. A 35-year-old woman with a history of Hodgkin lymphoma treated with mantle radiation in childhood presents with thyroid nodules. Her thyroid function tests are near normal. She has multiple nodules in her thyroid gland, which raises concern for possible malignancy. Among the risk factors, prior radiation exposure to the neck—especially during childhood—is a well-established risk factor for thyroid cancer. In fact, radiation exposure is linked to more aggressive thyroid neoplasms in some cases and is considered a significant poor prognostic indicator.
Thyroid nodules: While most thyroid nodules are benign, certain findings (history of radiation, rapid growth, fixation, lymph node involvement) are worrisome. Mantle radiation in childhood markedly increases the risk of papillary thyroid carcinoma, and these tumors can behave more aggressively.
Incorrect answers:
A. Cigarette smoking: Smoking is not a major poor prognostic factor for thyroid nodules/cancer, though it increases other malignancy risks.
B. Hyperthyroidism: Hyperfunctioning (hot) nodules are generally less likely to be malignant; this patient does not appear to be hyperthyroid anyway.
C. Iodine deficiency: Associated more with endemic goiter and some thyroid pathologies but not the strongest poor prognostic factor here.
D. Presence of multiple nodules: Multiple nodules can sometimes be less suspicious than a solitary dominant nodule. This does not outweigh the significance of radiation exposure.
Question 95:
The correct answer is A. The vesicular lesions on the child’s thumb and index finger, combined with a history of attending daycare, are consistent with herpetic whitlow, caused by herpes simplex virus (HSV). Oral acyclovir is the treatment of choice to reduce symptom duration and prevent complications.
Herpetic whitlow:
- Etiology: HSV-1 or HSV-2, often transmitted via direct contact with infected saliva or skin.
- Clinical features: Painful vesicular lesions on the fingers, mainly in children or healthcare workers.
Treatment:
- Oral acyclovir for 7–10 days.
- Avoid rupture of lesions to prevent secondary bacterial infection.
Incorrect answers:
B. Oral cephalexin: Used for bacterial infections, not HSV.
C. Oral clindamycin: Inappropriate for viral conditions.
D. Topical mupirocin: Used for bacterial skin infections, such as impetigo.
E. Topical silver sulfadiazine: Used for burns, not viral infections.
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Question 96:
The correct answer is D. A 70-year-old man with known coronary artery disease (including an MI 2 years ago) is on appropriate post-MI therapy with a beta-blocker (metoprolol), a statin (atorvastatin), and low-dose aspirin. His blood pressure is 150/95 mm Hg, which is above goal for someone with CAD. Patients with atherosclerotic disease, especially post-MI, benefit from an ACE inhibitor to reduce cardiac remodeling, manage hypertension, and improve long-term survival.
Post-MI guidelines recommend an ACE inhibitor (like lisinopril) unless contraindicated, especially in the presence of hypertension, left ventricular dysfunction, or diabetes. Lisinopril helps reduce afterload, limits adverse remodeling, and confers mortality benefit in CAD.
Decrease mortality in post-MI patients: Beta-blocker, ACE inhibitor, Spironolactone, SGLT2 inhibitors (in diabetic patients).
Incorrect answers:
A. Amlodipine: A calcium channel blocker used for hypertension and angina, but ACE inhibitors are first-line post-MI to improve survival
B. Clonidine: A centrally acting antihypertensive; not standard for post-MI mortality reduction or first-line for chronic hypertension in this setting.
C. Hydrochlorothiazide: A thiazide diuretic can help with BP but is less effective than an ACE inhibitor for post-MI mortality benefit and remodeling protection.
E. No additional pharmacotherapy is indicated: The patient has elevated BP and would benefit from an ACE inhibitor for both BP control and secondary prevention.
Question 97:
The correct answer is B. This 57-year-old woman presents with chest pain and ECG findings of ST-segment elevation and Q waves in leads II, III, and aVF, indicating an acute inferior ST-segment elevation myocardial infarction (STEMI). Immediate administration of oral aspirin (325 mg, chewed) is critical as it reduces platelet aggregation and the risk of thrombus propagation, significantly improving outcomes in acute MI.
Initial stabilization of STEMI:
- Supplemental oxygen: Only if SaO₂ <90% or dyspnea is present.
- Aspirin 325 mg: Chewed to ensure rapid absorption.
- P2Y12 inhibitor (e.g., clopidogrel): To inhibit platelet aggregation.
- Sublingual nitrates: For chest pain relief unless contraindicated (e.g., hypotension, right ventricular infarct).
- Beta blockers: Unless contraindicated (e.g., acute heart failure or bradycardia).
- High-dose statin: To stabilize atherosclerotic plaques.
- Anticoagulation: Choice depends on planned revascularization (e.g., unfractionated heparin for PCI).
Reperfusion therapy:
- Percutaneous coronary intervention (PCI): Preferred within 90 minutes.
- Thrombolysis: If PCI is unavailable within 120 minutes.
Incorrect answers:
A. Intramuscular morphine sulfate: Morphine is reserved for severe, persistent pain and is not the first-line intervention.
C. Oral diltiazem: Calcium channel blockers are contraindicated in STEMI as they can worsen myocardial ischemia.
D. Subcutaneous enoxaparin: Important for anticoagulation but not the initial treatment.
E. Sublingual nitroglycerin: Effective for chest pain but does not replace the critical role of aspirin in reducing mortality.
Block 6
Question 98:
The correct answer is D. This 31-year-old woman has acute viral pharyngitis with vesicular lesions on the tonsils and a household contact (child) with a febrile illness and rash on the hands and feet, findings most consistent with coxsackie A (herpangina/hand-foot-mouth). Management is supportive—pain control and hydration—so ibuprofen (or acetaminophen) is the most appropriate therapy.
Incorrect answers:
A. Acyclovir: Antiviral therapy is indicated for primary HSV pharyngitis, not for typical coxsackie enteroviral infections.
B. Amoxicillin: Antibiotics are unnecessary for viral pharyngitis and risk adverse effects.
C. Amoxicillin–clavulanic acid: Also inappropriate—no evidence of bacterial infection.
E. Prednisone: Systemic steroids are not indicated for uncomplicated viral pharyngitis and may be harmful in some infections.
Question 99:
The correct answer is C. This 4-month-old male presents with lethargy, weakness, constipation, and laboratory findings of hypokalemia, hypophosphatemia, and a nonanion gap metabolic acidosis (low bicarbonate, normal chloride). These findings are consistent with renal tubular acidosis (RTA), specifically type II (proximal) RTA. Prolonged metabolic acidosis impairs bone mineralization, leading to osteomalacia.
Type II RTA: Impaired bicarbonate reabsorption in the proximal tubule leads to:
- Loss of bicarbonate (nonanion gap metabolic acidosis).
- Hypokalemia due to potassium wasting.
- Impaired phosphate reabsorption, contributing to poor bone mineralization.
Effects on bone: Chronic acidosis and phosphate wasting cause osteomalacia in children (or rickets if severe).
Management:
Alkali supplementation (e.g., sodium bicarbonate).
Potassium and phosphate repletion.
Incorrect answers:
A. Congestive heart failure: No evidence of cardiac disease.
B. Cushing syndrome: Unlikely in an infant without characteristic findings (e.g., growth delay, obesity, hypertension).
D. Type 1 diabetes mellitus: No hyperglycemia or signs of diabetes are present.
Question 100:
The correct answer is B. This 11-year-old girl presents with diabetic ketoacidosis (DKA), evidenced by hyperglycemia (glucose 693 mg/dL), high anion gap metabolic acidosis (pH 7.16, base excess −16), and ketosis (elevated serum acetone). DKA is a medical emergency requiring prompt treatment to correct hyperglycemia, acidosis, and dehydration. The primary treatment is a continuous infusion of intravenous short-acting insulin to reduce blood glucose and suppress ketogenesis.
Diabetic ketoacidosis (DKA) management:
Volume resuscitation: Initial isotonic saline to restore intravascular volume.
Insulin therapy: Continuous infusion of IV short-acting insulin.
Electrolyte management: Monitor potassium closely; insulin drives potassium into cells, risking hypokalemia.
Correction of acidosis: Acidosis typically resolves with insulin therapy and volume expansion. Sodium bicarbonate is not routinely recommended unless pH <6.9.
Incorrect answers:
A. Bolus of intravenous sodium bicarbonate: Reserved for severe acidosis (pH <6.9), as it can worsen cerebral edema in children with DKA.
C. Intermittent boluses of intravenous short-acting insulin: Continuous infusion is preferred to maintain steady glucose control and ketogenesis suppression.
D. Subcutaneous administration of half short-acting and half intermediate-acting insulin: Subcutaneous insulin is not used initially in DKA due to unreliable absorption.
E. Subcutaneous administration of intermediate-acting insulin: Not effective in acute DKA management, as IV insulin is required.
Question 101:
The correct answer is E. The patient develops headache, decreased consciousness, extensor posturing, and hypertonia, which are signs of cerebral edema, a rare but serious complication of DKA. Cerebral edema is more common in children and occurs due to rapid osmotic shifts during treatment. Immediate administration of mannitol is required to reduce intracranial pressure and prevent further neurologic damage.
Pathophysiology: Rapid correction of hyperglycemia and acidosis can lead to intracellular fluid shifts and brain swelling.
Risk factors: younger age, severe acidosis, overly rapid fluid administration, or failure to monitor sodium levels.
Symptoms: Severe headache, altered mental status, seizures, bradycardia, and signs of increased intracranial pressure.
Management:
- Mannitol (or hypertonic saline): Osmotic agent to reduce cerebral edema.
- Reduce the rate of IV fluids and insulin infusion.
- Monitor closely in an intensive care setting.
Incorrect answers:
A. Administration of sodium bicarbonate: Sodium bicarbonate worsens cerebral edema and is not recommended.
B. CT scan of the head: Cerebral edema is a clinical diagnosis. Imaging may delay life-saving treatment.
C. EEG: The altered mental status and posturing are due to cerebral edema, not seizures. EEG is unnecessary.
D. Fosphenytoin therapy: The symptoms are not due to seizures, making antiepileptic therapy inappropriate.
Question 102:
The correct answer is A. This 25-year-old woman with polycystic ovary syndrome (PCOS) is at increased risk for developing type 2 diabetes mellitus (T2DM). PCOS is characterized by insulin resistance, which predisposes patients to hyperglycemia and subsequent diabetes. Counseling on lifestyle modifications and regular diabetes screening is essential.
Pathophysiology: Insulin resistance is central to PCOS and contributes to hyperandrogenism and anovulation. Increased risk of developing metabolic syndrome and T2DM.
Management: Annual diabetes screening with fasting glucose, oral glucose tolerance test, or HbA1c. Weight loss and exercise are first-line treatments.
Incorrect answers:
B. Hypertension: PCOS increases the risk of hypertension, but diabetes is the more significant risk in this patient.
C. Hypothyroidism: There is no evidence of thyroid dysfunction in this patient.
D. Nephrotic syndrome: Unrelated to PCOS.
E. Uterine cancer: Risk is increased with chronic anovulation, but diabetes is a more immediate concern.
Question 103:
The correct answer is B. This patient with progressive dyspnea, orthopnea, and new S3 has developed symptomatic severe mitral regurgitation leading to left-sided heart failure. She was previously asymptomatic with known MR, but now presents with clear evidence of decompensation despite medical therapy. The next step is evaluation for surgical (or transcatheter) mitral valve repair or replacement.
Indications for mitral valve surgery include symptomatic severe MR, asymptomatic severe MR with LV dysfunction (LVEF ≤60% or LV end-systolic diameter ≥40 mm), acute severe MR (e.g., papillary muscle or chordal rupture), or severe MR requiring concurrent cardiac surgery (e.g., CABG).
Incorrect answers:
A. Add amlodipine to her medication regimen: Amlodipine lowers blood pressure but does not treat regurgitant volume overload or valve dysfunction.
C. Increase the doses of hydrochlorothiazide and lisinopril: Escalating medical therapy provides only temporary relief and does not address the mechanical defect causing regurgitation.
D. Recommend a low-sodium diet that includes low-fat dairy products and fresh fruits and vegetables: Lifestyle modification is supportive but insufficient for advanced valvular disease.
E. Recommend starting a low-impact aerobic exercise regimen for 30 minutes daily: Exercise should be deferred until after surgical correction in symptomatic valve disease.
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Question 104:
The correct answer is D. This patient is on methadone maintenance therapy and expresses a desire to breastfeed. Methadone use is not a contraindication to breastfeeding, provided the dose is stable and the mother avoids other substances. Encouraging breastfeeding can enhance maternal-child bonding and improve neonatal outcomes, provided the baby is monitored for withdrawal symptoms.
Methadone and breastfeeding:
Methadone is considered safe during breastfeeding at therapeutic doses.
Breastfeeding reduces neonatal withdrawal severity by providing low levels of methadone in breast milk.
Cocaine and amphetamines are contraindicated in breastfeeding due to their potential neurotoxic effects on the infant.
Incorrect answers:
A. There is no mention of HIV positivity in the patient’s history.
B. Methadone maintenance is not a contraindication to breastfeeding.
C. Oversimplifies the risks; close monitoring is still needed.
E. Incorrect, as cocaine and amphetamines are contraindicated.
Question 105:
The correct answer is B. This patient presents with a right-sided pleural effusion and Light’s criteria show the effusion is exudative (pleural/serum protein ratio = 3.9/5.3 = 0.74 > 0.5, pleural/serum LDH ratio = 169/189 = 0.89 > 0.6). Given the serosanguineous fluid and negative cytology, malignancy remains a strong consideration—especially in an older man with obesity, sleep apnea, and no infection symptoms. The next step is CT scan of the chest to evaluate for malignancy, pulmonary embolism, or other structural causes of exudative effusion.
Incorrect answers:
A. Bronchoscopy: Indicated only if CT shows an endobronchial lesion or hemoptysis or airway obstruction is suspected; not the initial step here.
C. Echocardiography: Used to evaluate transudative effusions (e.g., heart failure). This effusion is exudative by Light’s criteria.
D. Furosemide therapy: Appropriate for heart failure–related transudates, but this is exudative, not a volume-overload process.
E. Moxifloxacin therapy: Empiric antibiotics are used for parapneumonic effusions, but no infectious symptoms or low pH suggestive of empyema are present.
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Question 106:
The correct answer is C. This patient experienced a generalized tonic-clonic seizure (evidenced by tongue bite, postictal confusion, and amnesia) triggered by sleep deprivation and excessive caffeine intake. Both are known precipitants that lower seizure threshold in susceptible individuals. His work schedule, prolonged wakefulness for exams, and stimulant use created the perfect environment for a seizure in an otherwise healthy adult. MRI, EEG, and labs are normal, confirming a provoked seizure rather than epilepsy.
Prevention focuses on adequate sleep hygiene and caffeine moderation.
Incorrect answers:
A. Alcohol avoidance: His history shows modest, consistent intake without evidence of withdrawal or intoxication; not the precipitating factor.
B. Discontinuation of lisinopril: ACE inhibitors do not cause seizures; his dose should continue for hypertension.
D. Occupation change: Working night shifts contributes to poor sleep but can be mitigated with proper rest; not an absolute necessity.
E. Tobacco cessation: Improves health overall but has no direct impact on seizure recurrence.
Question 107:
The correct answer is B. This 52-year-old woman presents with wrist pain following a fall and imaging findings consistent with a scaphoid fracture. The absence of swelling but tenderness with wrist movement is characteristic of this injury. Scaphoid fractures are at high risk for nonunion and avascular necrosis due to the retrograde blood supply to the proximal segment. The appropriate management involves immobilization with a plaster cast that incorporates the thumb to stabilize the fracture and promote healing.
Typically due to a fall on an outstretched hand (FOOSH).
Clinical features:
- Pain in the anatomical snuffbox.
- Tenderness with wrist flexion or extension.
- Often minimal swelling or bruising.
Imaging:
- X-rays may initially appear normal; further imaging (e.g., MRI or CT) may be needed if clinical suspicion is high.
Management:
- Nondisplaced fractures: Immobilization with a thumb spica cast for 6–8 weeks.
- Displaced fractures: Referral to an orthopedic surgeon for surgical fixation.
Incorrect answers:
A. Apply an elastic wrist bandage: Insufficient stabilization for a scaphoid fracture, which requires rigid immobilization.
C. Apply a plastic wrist splint: A splint does not provide the rigid immobilization necessary to prevent complications like nonunion or avascular necrosis.
D. Begin daily aspirin treatment and do not restrict use of the hand: Aspirin has no role in managing scaphoid fractures, and unrestricted use risks worsening the injury.
E. Refer her to an occupational therapist: Premature, as proper immobilization is the priority before rehabilitation.
Question 108:
The correct answer is E. This patient with sudden-onset severe chest and back pain, hypotension, pulse discrepancy (radial > femoral), and diastolic murmur has an acute type A aortic dissection. CT angiography confirms dissection involving the ascending aorta, which can extend into the aortic root and cause aortic regurgitation and cardiac tamponade—both life-threatening. The definitive management is emergent surgical repair with replacement of the aortic root and ascending aorta.
Incorrect answers:
A. Coronary angiography: Contraindicated in suspected aortic dissection due to risk of aortic rupture; indicated for acute coronary syndromes, not here.
B. CT scan of the head: Not indicated unless neurological symptoms develop; current instability demands immediate surgical management.
C. Norepinephrine infusion: Vasoconstrictors can worsen the dissection by increasing shear stress; avoid pressors unless absolutely necessary.
D. Placement of an intra-aortic balloon pump: Contraindicated; may propagate the dissection or cause aortic rupture.
Question 109:
The correct answer is C. This 20-year-old male with urethral discharge and unprotected intercourse is diagnosed with gonorrhea and chlamydia. Despite treatment for these infections, he is at risk for HIV, especially given the unprotected sexual exposure. HIV serology testing is recommended in 3 months to detect seroconversion.
HIV screening in sexually transmitted infections (STIs):
- Patients with STIs have a higher risk of HIV due to shared transmission routes.
- Initial testing may not detect acute HIV; repeat testing at 3 months is necessary to confirm the absence of infection.
Incorrect answers:
A. Consult with the patient’s parents: Not required as the patient is an adult.
B. Schedule follow-up examination in 1 week: Not needed unless symptoms persist or worsen.
D. No specific follow-up is necessary: Follow-up for HIV screening is critical.
Question 110:
The correct answer is D. This patient presents with symptoms and signs of congestive heart failure (CHF), as evidenced by progressive dyspnea, bilateral crackles, an S3 heart sound, and pitting edema. The electrocardiogram shows low voltage QRS complexes, likely due to chronic structural heart changes. Although beta-blockers (e.g., metoprolol) are commonly used for heart failure, they are contraindicated in patients with acute decompensated heart failure (ADHF) due to their negative inotropic effect, which can exacerbate pulmonary edema and decrease cardiac output.
Beta-blockers in CHF:
Indicated for chronic heart failure with reduced ejection fraction to improve survival.
Contraindicated in acute decompensation due to their potential to worsen fluid retention and pulmonary congestion.
Incorrect answers:
A. Digoxin: Increases contractility and was sometimes used for symptomatic relief in heart failure, though it does not improve mortality.
B. Furosemide: A loop diuretic, essential for fluid overload management in ADHF
C. Lisinopril: An ACE inhibitor, beneficial for both acute and chronic heart failure by reducing afterload.
E. Spironolactone: An aldosterone antagonist, indicated for NYHA class II-IV heart failure to improve survival.
Question 111:
The correct answer is D. Hypophosphatemia. This patient has chronic alcoholism, malnutrition, and recent cessation of alcohol intake. Following hospitalization, he is receiving intravenous fluids and nutritional supplementation, placing him at high risk for refeeding syndrome. Refeeding syndrome occurs when nutritional support is initiated in a chronically malnourished patient, leading to rapid intracellular shifts of electrolytes. Hypophosphatemia is the hallmark laboratory abnormality and can result in respiratory failure, muscle weakness, arrhythmias, seizures, and hemolysis.
Patients at particularly high risk include those with alcoholism, anorexia nervosa, prolonged fasting, cancer-related cachexia, and severe weight loss. Prevention involves administration of thiamine before nutritional replenishment, gradual reintroduction of calories, and close monitoring of electrolytes.
Incorrect answers:
A. Hypocalcemia: Hypocalcemia may occur in hospitalized patients but is not the characteristic electrolyte abnormality of refeeding syndrome.
B. Hypokalemia: Hypokalemia can develop during refeeding syndrome; however, hypophosphatemia is the hallmark finding and carries the greatest clinical significance.
C. Hyponatremia: Hyponatremia is not a defining feature of refeeding syndrome and is less likely than hypophosphatemia in this setting.
E. Hyperkalemia: Refeeding syndrome is associated with intracellular potassium shifts resulting in hypokalemia rather than hyperkalemia.
Question 112:
The correct answer is C. This patient with tinnitus, tachypnea, and mixed respiratory alkalosis + metabolic acidosis after ingestion of an “unspecified pain medication” has acute salicylate (aspirin) toxicity. Salicylates directly stimulate the respiratory center (↓ PCO₂ → respiratory alkalosis) and cause anion gap metabolic acidosis by uncoupling oxidative phosphorylation. The best next step in management is administration of sodium bicarbonate, which alkalinizes the serum and urine, promoting ionization of salicylate (salicylate⁻) and enhancing renal excretion (ion trapping).
Incorrect answers:
A. Administration of lipid emulsion: Used for lipophilic drug overdoses such as local anesthetics (e.g., bupivacaine), not for salicylate poisoning.
B. Administration of N-acetylcysteine: The antidote for acetaminophen toxicity, not aspirin toxicity.
D. Endotracheal intubation: Reserved for airway compromise or coma; mechanical ventilation can worsen acidosis by retaining CO₂.
E. Supportive care only: Not sufficient for moderate to severe salicylate poisoning; active elimination therapy (alkalinization) is essential.
Question 113:
The correct answer is A. The patient has mild persistent asthma, as evidenced by symptoms occurring several times a week and frequent use of a short-acting beta-agonist (SABA) inhaler. Based on the step-up strategy for asthma management, she requires additional controller therapy. The next appropriate step is adding a low-dose inhaled corticosteroid (ICS), such as fluticasone, to address airway inflammation and reduce symptom frequency.
Asthma treatment ladder:
- Step 1 & 2: For patients with symptoms occurring less than daily, use ICS-formoterol as needed.
- Step 3: For patients with symptoms on most days or waking with asthma, daily low-dose ICS-formoterol is recommended.
- Step 4: For patients with persistent daily symptoms or decreased lung function, medium- to high-dose ICS-formoterol should be used.
- Step 5: Patients with uncontrolled symptoms on Step 4 may require high-dose ICS-formoterol, a long-acting muscarinic antagonist (LAMA), or biologic therapy.
This patient fits into Step 3 due to her symptom pattern, making the addition of an ICS essential.
Incorrect answers:
B. Add inhaled tiotropium: LAMA (tiotropium) is reserved for Step 5 or severe asthma cases uncontrolled with ICS-LABA combinations.
C. Add oral azithromycin: Azithromycin is not part of standard asthma management.
D. Add oral montelukast: Montelukast, a leukotriene receptor antagonist, is less effective than ICS and is generally reserved for patients with specific triggers, such as allergies or exercise-induced asthma.
E. Increase the dosage of the inhaled albuterol to four times daily: This approach does not address the underlying inflammation and increases reliance on SABA, which is not ideal for asthma control.
F. Prescribe a 5-day course of oral prednisone: Systemic corticosteroids are used for exacerbations, not as maintenance therapy for mild persistent asthma.
Question 114:
The correct answer is D. This 9-year-old boy presents with sudden, repetitive motor (eye blinking) and vocal (throat clearing) tics occurring frequently and interfering with his daily activities, consistent with Tourette syndrome. Tourette syndrome is a neurodevelopmental disorder characterized by the presence of both motor and vocal tics for over one year. A common comorbidity in patients with Tourette syndrome is obsessive-compulsive disorder (OCD), which often develops later in life.
Tourette syndrome diagnostic criteria:
- Both motor and vocal tics are present for at least 1 year.
- Onset before age 18.
- Tics may wax and wane but are often exacerbated by stress.
Comorbidities:
- OCD
- ADHD
Incorrect answers:
A. Hepatolenticular degeneration (Wilson disease): Presents with movement disorders (e.g., tremor, dystonia) and hepatic dysfunction, but this patient has no supporting history or examination findings.
B. Huntington disease: Rare in children; typically presents with chorea, behavioral changes, and dementia in adults.
C. Intellectual disability: The patient’s normal school performance and developmental history exclude this diagnosis.
E. Seizure disorder: Seizures involve episodes of altered consciousness or postictal states, which are absent in this patient.
Question 115:
The correct answer is A. This adolescent’s chronic RLQ pain, weight loss, recurrent oral aphthous ulcers, growth failure, and focal right lower-quadrant fullness point to Crohn disease (transmural, ileocecal–predominant inflammation). Crohn disease commonly causes perianal disease — fissures, abscesses, and anal fistulae — because inflammation is transmural and can track to the skin.
Incorrect answers:
B. Colonic carcinoma: Risk of CRC is associated with longstanding ulcerative colitis (extensive colitis) after many years; not the typical short-term pediatric presentation of Crohn disease.
C. Diabetes mellitus: No link between his GI symptoms/oral ulcers and new diabetes.
D. Progressive pulmonary failure: Pulmonary fibrosis or severe lung disease is not a common complication of Crohn disease in adolescents.
E. Toxic megacolon: More classically a complication of ulcerative colitis, rare in isolated ileocecal Crohn disease.
Question 116:
The correct answer is A. This elderly man with progressive tibial bowing, bone pain, and X-ray showing cortical thickening and sclerosis has Paget disease of bone (osteitis deformans). The disease is caused by increased osteoclastic bone resorption followed by disorganized bone formation, leading to deformity and bone pain. The first-line pharmacotherapy is a bisphosphonate (e.g., alendronate), which inhibits osteoclast activity and normalizes bone turnover.
Incorrect answers:
B. Calcitonin, intramuscularly: Calcitonin can reduce bone resorption but is less effective than bisphosphonates and is now reserved for patients intolerant to them.
C. Calcitonin, nasally: Same as above — lower efficacy; used rarely for short-term pain control.
D. Mithramycin, intravenously: A cytotoxic antibiotic with significant side effects; formerly used before bisphosphonates became standard.
E. Naproxen, orally: NSAIDs can help mild pain but do not alter disease progression.
Question 117:
The correct answer is A. The biopsy showing B-cell lymphocytes positive for CD20 in a gastric ulcer suggests mucosa-associated lymphoid tissue (MALT) lymphoma. This condition is strongly associated with Helicobacter pylori infection. First-line treatment involves H. pylori eradication with clarithromycin-based triple therapy, which can induce remission in early-stage MALT lymphoma.
Standard triple therapy includes:
Clarithromycin.
Amoxicillin.
Proton pump inhibitor (e.g., omeprazole).
If lymphoma persists after eradication, consider chemotherapy or radiation.
Incorrect answers:
B. Cyclophosphamide and metronidazole therapy: Not appropriate for MALT lymphoma.
C. Radiation therapy: Reserved for H. pylori-negative or refractory MALT lymphoma.
D. Rituximab therapy: Used for advanced or aggressive lymphomas, not initial management of MALT lymphoma.
E. Surgical resection: Rarely indicated as MALT lymphoma responds to medical therapy.
Block 7
Question 118:
The correct answer is A. This young man presents with acute dilated cardiomyopathy following a viral prodrome (fever, chills, recent illness), elevated BNP, S₃ gallop, and LV systolic dysfunction (EF 40%) — classic for viral myocarditis (often Coxsackie B or adenovirus). In otherwise healthy young adults, viral myocarditis–induced systolic dysfunction is often reversible, with complete recovery over weeks to months as inflammation resolves.
Incorrect answers:
B. Mild diastolic dysfunction: Diastolic dysfunction is typical of restrictive or hypertrophic cardiomyopathy, not acute viral myocarditis.
C. Pulmonary embolism: PE presents with acute dyspnea and hypoxia but not LV dilation or S₃ gallop.
D. Recurrent pericarditis: This condition causes chest pain relieved by leaning forward and a friction rub — not LV dysfunction.
E. Severe systolic heart failure requiring cardiac transplant: A minority develop irreversible damage, but most young patients recover fully
Question 119:
The correct answer is A. This 25-year-old man is requesting HPV vaccination. The HPV vaccine is recommended for all individuals from age 9 through age 26, regardless of prior sexual activity, HPV exposure, or sexual orientation. It protects against HPV strains associated with genital warts and anogenital/oropharyngeal cancers. Men who have sex with men are at increased risk of HPV infection and thus particularly benefit from vaccination. There is no need for prior serologic testing or cytologic screening before vaccination.
Incorrect answers:
B. Obtain HPV serologic testing: Not indicated; there is no clinical HPV serology test for determining immunity or prior exposure.
C. Perform an anal Pap smear for cytologic examination: Screening for anal cancer in men who have sex with men is not routinely recommended unless HIV positive.
D. Use motivational interviewing to encourage abstinence: This patient uses condoms and is in a stable relationship; abstinence counseling is unnecessary and inappropriate.
Question 120:
The correct answer is E. This 36-year-old woman presents with acute abdominal pain, nausea, vomiting, and significantly elevated lipase, suggesting acute pancreatitis. The most common causes of acute pancreatitis are gallstones and alcohol use. Given her mild bilirubin elevation and no history of heavy alcohol use, gallstone pancreatitis is the most likely etiology. Right upper quadrant (RUQ) ultrasonography is the initial imaging modality to evaluate for gallstones.
Diagnostic criteria for acute pancreatitis (requires 2 of 3):
- Acute epigastric pain radiating to the back.
- Elevated lipase or amylase (≥3 times the upper limit of normal).
- Imaging findings consistent with pancreatitis.
Etiology:
Gallstones (most common in non-alcoholics).
Alcohol use.
Hypertriglyceridemia.
Imaging:
RUQ ultrasonography for suspected gallstone pancreatitis.
CT abdomen if etiology remains unclear.
Incorrect answers:
A. CT scan of the abdomen with contrast: Used if the diagnosis is uncertain or for complications of pancreatitis, but ultrasonography is the first-line test for suspected gallstones.
B. Fenofibrate therapy: Indicated for hypertriglyceridemia-related pancreatitis, not gallstone pancreatitis.
C. Imipenem cilastatin therapy: Antibiotics are not routinely used in acute pancreatitis unless there is evidence of infection (e.g., pancreatic necrosis).
D. Insulin therapy: Not relevant in this scenario as there is no evidence of hyperglycemia or diabetic ketoacidosis.
Question 121:
The correct answer is C. This is a tricky question. Even though affected people appear in several generations, the family tree is too small and unclear to determine one definite pattern of inheritance. It could be autosomal dominant with reduced penetrance or variable expression, an X-linked trait with an unusual pattern, or even new (de novo) cases or environmental mimics (phenocopies). Because there are only a few family members to analyze and some information is missing, we cannot confidently decide whether this follows an autosomal dominant, X-linked, or chromosomal cause.
Therefore, the best answer is that the inheritance pattern cannot be determined from this pedigree
Incorrect answers:
A. It is an autosomal dominant disorder: Although vertical transmission could suggest autosomal dominant inheritance, the pedigree lacks sufficient informative transmissions and shows uncertainty (possible skipped generations/variable penetrance), so autosomal dominant cannot be concluded with confidence.
B. It is a chromosomal aneuploidy: Aneuploidies cause multisystem findings and reduced fertility and usually are not transmitted in a clean Mendelian vertical pattern seen here.
D. It is an X-linked dominant condition: X-linked dominant disorders produce a distinctive pattern (affected mothers transmit to sons and daughters; no male-to-male transmission), which cannot be confirmed or excluded from this small pedigree.
E. It is an X-linked recessive condition: X-linked recessive traits predominantly affect males and show carrier females; the equal involvement of both sexes and the limited data make this assignment unlikely and not demonstrable from the pedigree.
Question 122:
The correct answer is B. This patient with autosomal dominant polycystic kidney disease has an elevated creatinine (2.1 mg/dL) and BUN 30 mg/dL, indicating reduced renal function. Current kidney function (GFR/creatinine) correlates strongly with prognosis and need for dialysis or transplant. Total kidney volume and genetic mutation type also predict progression. Plasma copeptin is an emerging biomarker for ADPKD but is less established than measured kidney function.
Incorrect answers:
A. BMI: Higher BMI may worsen comorbidity but is not a primary predictor of ADPKD progression.
B. Kidney function: Reduced GFR/raised creatinine most strongly indicates poorer prognosis and need for renal replacement therapy.
C. Number of kidney cysts: Cyst burden matters, but total kidney volume and function are more predictive than simple cyst count.
D. Plasma copeptin concentration: Associated with progression but not yet the strongest or standard prognostic marker.
E. Serum LDL concentration: Relevant for cardiovascular risk, not for renal prognosis in ADPKD.
F. Urine sodium concentration: Reflects intake/volume status; not a marker of long-term ADPKD prognosis.
Question 123:
The correct answer is A. This patient’s combination of nasal congestion, nasal polyps, anosmia, and wheezing is characteristic of aspirin-exacerbated respiratory disease (Samter triad) — chronic rhinosinusitis with nasal polyposis, asthma, and sensitivity (actual or potential) to aspirin or other NSAIDs. The presence of associated shortness of breath and wheezing indicates involvement of the lower airways, predicting progression from isolated allergic rhinitis to asthma. Even though this patient has not yet taken aspirin, patients with this triad are predisposed to develop severe bronchospasm after aspirin or NSAID exposure.
Incorrect answers:
B. Family history of similar symptoms: Suggests a genetic predisposition to allergic rhinitis but does not predict development of asthma or aspirin sensitivity.
C. Loss of sense of smell: A common finding in chronic nasal polyposis but not predictive of a more serious underlying respiratory condition.
D. Perennial nature of symptoms: Indicates chronic allergen exposure but does not specifically increase risk of asthma or systemic disease progression.
Question 124:
The correct answer is A. This patient with allergic rhinitis and persistent wheezing and shortness of breath despite environmental control measures likely has coexistent asthma. The most appropriate next step is initiation of inhaled corticosteroid therapy (inhaled fluticasone), which is the cornerstone of treatment for persistent asthma. Inhaled corticosteroids reduce airway inflammation, improve airflow, and prevent exacerbations. Addressing the lower-airway inflammation directly is necessary since allergen avoidance alone has been insufficient.
Incorrect answers:
B. Nasal cromolyn: This medication helps control allergic rhinitis but has no benefit for lower-airway inflammation or asthma symptoms.
C. Nasal oxymetazoline: A topical α-agonist decongestant useful for short-term nasal congestion relief; prolonged use can cause rebound congestion (rhinitis medicamentosa).
D. Oral fexofenadine: An antihistamine that alleviates sneezing and rhinorrhea but does not address bronchial inflammation or wheezing due to asthma.
Question 125:
The correct answer is D. This patient with fever, cough with purulent sputum, and focal infiltrate on chest x-ray has community-acquired pneumonia (CAP) requiring inpatient treatment. The antibiotic regimen must be chosen carefully because she has myasthenia gravis, a condition in which certain antibiotics can exacerbate neuromuscular weakness and precipitate respiratory failure.
- Fluoroquinolones (e.g., levofloxacin) and macrolides (e.g., azithromycin) impair neuromuscular transmission and are contraindicated in myasthenia gravis.
- Therefore, the appropriate regimen for hospitalized CAP in this patient is ceftriaxone (for S. pneumoniae, H. influenzae, Klebsiella) plus doxycycline (for atypical coverage such as Mycoplasma, Legionella, Chlamydia).
Incorrect answers:
A. Amoxicillin-clavulanic acid: Inadequate for inpatient CAP because it lacks atypical coverage.
B. Azithromycin: Contraindicated — worsens myasthenic symptoms.
C. Cefepime and tobramycin: Used for healthcare-associated pneumonia; tobramycin (aminoglycoside) also worsens myasthenia.
E. Levofloxacin: Excellent CAP coverage but contraindicated in myasthenia gravis.
F. Trimethoprim-sulfamethoxazole: Not used for typical CAP pathogens; can worsen hyperkalemia or cause marrow suppression.
Question 126:
The correct answer is C. This patient on chronic opioid therapy is suspected of opioid diversion (selling medication) based on his friend’s report. The appropriate next step is to objectively assess medication adherence before making assumptions. A random urine drug test should be obtained to determine whether the patient is actually taking oxycodone. Absence of oxycodone or its metabolites confirms nonadherence/diversion and guides further action.
Incorrect answers:
A. Discontinue oxycodone: Should not be done immediately without verification; first confirm diversion through urine testing.
B. Notify the police: Breach of confidentiality; physicians must first confirm diversion before reporting to authorities.
D. Refer the patient to a methadone clinic: Methadone is for opioid use disorder, not suspected diversion without evidence of misuse.
E. Switch oxycodone to a different pain medication: Inappropriate; diversion risk applies to all opioids and must be confirmed before any change.
Question 127:
The correct answer is A. This healthy 14-year-old boy is undergoing a routine sports physical. Cardiac auscultation reveals a physiologic (normal) splitting of S₂, which widens with inspiration and narrows with expiration — a normal high-yield finding in adolescents and young adults due to increased venous return and delayed pulmonic valve closure. He has no history or findings suggestive of cardiac disease; therefore, it is appropriate to approve participation in sports with no further testing.
Incorrect answers:
B. Chest x-ray: Indicated only if there are clinical signs of pulmonary or structural heart disease (eg, cyanosis, murmurs, or respiratory symptoms).
C. Exercise stress test: Used to evaluate exertional chest pain, dyspnea, or suspected ischemia; not indicated in an asymptomatic teen.
D. ECG: Routine ECG screening in asymptomatic athletes without risk factors is not recommended.
E. Echocardiography: Reserved for abnormal physical findings (eg, pathologic murmurs, fixed splitting of S₂, clicks, or thrills); not necessary when the exam demonstrates a normal physiologic split.
Question 128:
The correct answer is E. This patient has newly diagnosed type 2 diabetes mellitus (A1c 8.3%) with normal blood pressure (129/79 mm Hg) and no microalbuminuria (<30 mg/24 h). The appropriate initial management includes lifestyle modification and metformin. ACE inhibitors are indicated in patients with diabetes who also have hypertension or albuminuria, which this patient does not have. Although statin therapy would generally be recommended for adults aged 40–75 with diabetes for primary prevention, statins are not listed among the answer choices. Therefore, no additional pharmacotherapy beyond glycemic management is indicated among the available options.
Incorrect answers:
A. 81-mg Aspirin: Used for secondary prevention or primary prevention in high ASCVD risk (>10%); not indicated here
B. Chlorthalidone: A thiazide diuretic for hypertension; blood pressure is normal.
C. Lisinopril: ACE inhibitors are recommended in diabetics with hypertension or albuminuria, which she lacks.
D. Metoprolol: Not used in initial diabetes management and can worsen glycemic control.
Question 129:
The correct answer is D. This patient presents with atrial fibrillation and rapid ventricular response secondary to thyroid storm, evidenced by hyperthyroid symptoms (goiter, weight loss, heat intolerance) and fever. Intravenous propranolol, a nonselective beta-blocker, controls the heart rate and reduces conversion of T4 to T3.
Thyroid storm management:
Beta-blockers (e.g., propranolol) to manage tachycardia and block T4 to T3 conversion.
Antithyroid drugs (e.g., propylthiouracil or methimazole).
Iodine to inhibit thyroid hormone release (given after antithyroid drugs).
Supportive care: Fluids, cooling, and glucocorticoids.
Incorrect answers:
A. Cardioversion: Not indicated in stable atrial fibrillation with underlying thyroid storm.
B. Intravenous dexamethasone: Used for thyroid storm but does not control heart rate acutely.
C. Intravenous diltiazem: Calcium channel blockers are less effective than beta-blockers in thyroid storm.
E. Oral potassium iodide: Should be administered after antithyroid drugs to prevent iodine uptake by the thyroid.
Question 130:
The correct answer is A. The patient presents with temporomandibular joint (TMJ) dysfunction, characterized by pain around the jaw, difficulty opening the mouth, and a snapping sensation at the joint. This condition is exacerbated by overuse of the TMJ, often from activities like gum chewing or eating hard foods, which increase stress on the joint. The lack of systemic symptoms and normal oral exam findings rule out infection or other inflammatory conditions.
Temporomandibular joint dysfunction (TMD) often presents with jaw pain, restricted jaw movement (“lockjaw”), and sometimes clicking or popping of the joint. Conservative management is the first step and typically includes:
- Avoiding hard or chewy foods and gum
- Practicing jaw relaxation exercises
- Using bite splints if indicated
- Applying warm compresses and considering NSAIDs for pain control
- Further interventions (eg, orthodontics, surgery) are reserved for refractory cases.
Incorrect answers:
B. Consult an orthodontist: Malocclusion or dental alignment issues are not implicated in this patient’s symptoms.
C. Cradle the phone receiver between shoulder and jaw: This can worsen TMJ stress and exacerbate symptoms.
D. Open and close her jaw widely three times daily: Excessive jaw movement can increase pain and inflammation.
E. Take oxycodone as needed for pain: Opioid analgesics are unnecessary for TMJ dysfunction and should be avoided.
Question 131:
The correct answer is A. A 27-year-old woman, 1 day postpartum, is motivated to breastfeed her newborn but is worried about returning to work in 4 weeks where she may not have easy breaks. She wonders how to maintain breast milk supply and continue breastfeeding despite her job constraints.
Key considerations in breastfeeding counseling
- Exclusive breastfeeding is recommended for about 6 months if possible.
- Women who return to work can maintain breastfeeding by pumping during scheduled breaks and storing breast milk.
- Employers are encouraged (and often legally required) to provide reasonable break time and a private space (other than a bathroom) for pumping.
Reassuring her that she can continue to breastfeed while creating a practical plan for pumping at work is crucial. This helps sustain milk supply and provides optimal nutrition for the infant.
Incorrect answers:
B. Encourage the patient to focus on breastfeeding and find a new job: Impractical and does not address realistic strategies for continued breastfeeding while employed.
C. Recommend that the patient not breastfeed: Contradicts established guidelines and the patient’s own wishes. Breastfeeding has significant benefits for both mother and child.
D. Remind the patient she must prioritize baby’s care: Vague and not a helpful, specific plan to manage pumping at work.
E. Suggest using both breastfeeding and bottle-feeding: While some mothers combine methods, introducing bottles too early can interfere with milk supply and latch. The first recommendation is typically to support exclusive breastfeeding with pumping strategies.
Question 132:
The correct answer is D. This patient has lateral medullary (Wallenberg) syndrome due to infarction of the posterior inferior cerebellar artery (PICA). His findings — vertigo, ipsilateral facial sensory loss, contralateral body sensory loss, dysphagia, hoarseness, dysarthria, ataxia, and ipsilateral Horner syndrome (ptosis, miosis) — all localize to the lateral medulla.
Because the medulla houses the respiratory centers (dorsal and ventral respiratory groups), injury in this region predisposes to central hypoventilation during sleep — the inability to automatically regulate breathing, leading to sleep-related hypoventilation or even apnea.
Incorrect answers:
A. Achalasia and gastroparesis: These are due to autonomic neuropathy (e.g., diabetes), not brainstem infarction.
B. Angle-closure glaucoma: Causes sudden painful vision loss, unrelated to brainstem stroke.
C. Orthostatic hypotension: Results from autonomic dysfunction but not characteristic of lateral medullary infarction.
E. Third-degree atrioventricular block: Results from cardiac conduction disease, not medullary involvement.
Question 133:
The correct answer is B. This frail, immobile 84-year-old has a sacral stage II pressure ulcer caused primarily by sustained pressure and shear; the single most important intervention to improve healing is pressure relief/off-loading (frequent repositioning, specialized mattress/pressure-reducing surfaces). Off-loading restores perfusion to the ischemic tissue and is the foundation of pressure-ulcer management; without it, other measures have limited effect.
Incorrect answers:
A. Hypercaloric diet: Nutrition (adequate calories/protein) supports healing but is adjunctive — it cannot overcome ongoing pressure-induced ischemia.
C. Silver sulfadiazine: Topical antimicrobial agents may control superficial microbial colonization but do not address the primary cause (pressure) and are not first-line for clean stage II ulcers.
D. Wound debridement: Debridement is indicated for necrotic or infected tissue; this ulcer has no significant necrosis or surrounding cellulitis, so debridement would not be the priority.
Question 134:
The correct answer is D. This postpartum woman with a tender, erythematous breast mass unresponsive to cephalexin and associated fever likely has lactational mastitis due to methicillin-resistant Staphylococcus aureus (MRSA). Failure to improve with β-lactam antibiotics (e.g., cephalexin, dicloxacillin) strongly suggests MRSA infection. Therefore, empiric treatment with IV vancomycin is indicated while awaiting aspiration results. Vancomycin covers MRSA and is safe for use in breastfeeding women.
Incorrect answers:
A. Intravenous ampicillin-sulbactam: Covers MSSA, gram-negative, and anaerobes but not MRSA.
B. Intravenous cefazolin: A first-generation cephalosporin effective against MSSA, not MRSA.
C. Intravenous piperacillin-tazobactam: Used for broad-spectrum infections (e.g., intra-abdominal, Pseudomonas), not necessary for mastitis.
E. Oral dicloxacillin: Standard first-line therapy for uncomplicated mastitis due to MSSA, but not for severe or MRSA-suspected infections.
Question 135:
The correct answer is F. This 67-year-old woman with osteopenia presents with a subacute history of hip pain, limited range of motion, and imaging findings of cortical thickening in the sub-trochanteric region, consistent with an atypical (pathological) femoral fracture. These fractures often occur with minimal trauma and require surgical fixation to stabilize the fracture and improve mobility.
Atypical femoral fractures is commonly associated with long-term bisphosphonate use due to suppressed bone remodeling.
Symptoms:
- Pain in the thigh or groin before a complete fracture.
- Imaging: Cortical thickening or transverse fracture line in the subtrochanteric or diaphyseal region.
Management:
- Surgical fixation for complete or unstable fractures.
- Discontinuation of bisphosphonates and transition to other therapies (e.g., teriparatide) for bone health.
Incorrect answers:
A. Bisphosphonate therapy: Contraindicated as this fracture type may be linked to bisphosphonate use.
B. Brace stabilization: Insufficient for stabilizing femoral fractures.
C. Calcitonin therapy: Not first-line for bone fracture management.
D. Cast immobilization: Ineffective for stabilizing femoral fractures.
E. Intra-articular dexamethasone injection: Not appropriate for fracture treatment.
G. Observation only: Delay in surgical fixation would worsen outcomes and mobility.
Question 136:
The correct answer is B. This patient presents with classic features of Graves disease: weight loss, tremor, anxiety, heat intolerance, lid lag, exophthalmos, diffuse goiter, and suppressed TSH. Untreated hyperthyroidism increases cardiac output, heart rate, and myocardial oxygen demand, leading to high-output heart failure due to persistent tachycardia, atrial fibrillation, and increased blood volume. This form of heart failure occurs even with preserved ejection fraction because of the metabolic and hemodynamic stress imposed by thyroid hormone excess.
Incorrect answers:
A. Chronic kidney disease: Not associated with hyperthyroidism; renal function is usually normal unless heart failure develops.
C. Fibromyalgia: Characterized by widespread musculoskeletal pain and fatigue, unrelated to thyroid hormone levels.
D. Glaucoma: Heredity is noted but unrelated to her thyroid disease; thyroid eye disease involves orbital inflammation, not intraocular pressure elevation.
E. Multiple sclerosis: Presents with neurological deficits (e.g., optic neuritis, weakness), not endocrine or metabolic symptoms.
Question 137:
The correct answer is C. A 68-year-old woman in the ICU for respiratory distress is now febrile, tachycardic, and has developed “lead pipe” rigidity. Her serum creatine kinase is elevated, suggesting significant muscle injury. She has been receiving haloperidol (an antipsychotic), benztropine, lithium, and other medications. The combination of severe muscle rigidity, hyperthermia, and elevated CK points strongly to neuroleptic malignant syndrome (NMS), which is most commonly caused by dopamine antagonists such as haloperidol.
NMS is characterized by:
- Severe muscle rigidity (“lead pipe” rigidity)
- Hyperthermia
- Autonomic instability (eg, unstable blood pressure, tachycardia)
- Elevated CK and potential rhabdomyolysis
Management requires immediate discontinuation of the offending agent (eg, haloperidol) plus supportive care and often dantrolene or bromocriptine.
Incorrect answers:
A. Benztropine: An anticholinergic used to treat medication-induced extrapyramidal symptoms; not primarily responsible for NMS.
B. Ciprofloxacin: An antibiotic given for presumed infection; discontinuing this would not address the acute muscle rigidity and hyperthermia.
D. Lorazepam: A benzodiazepine for agitation. While oversedation can cause altered mental status, it does not cause lead pipe rigidity and CK elevation.
E. Methylprednisolone: A corticosteroid used for inflammatory conditions; it does not cause NMS and would not be the priority to discontinue in this scenario.
That brings us to the end of the new Free 137 NBME Step 3 sample test answers and explanations. We hope this breakdown helped you better understand the reasoning behind the correct answers and why the other options were incorrect. Hopefully, this will give you an edge in acing your USMLE Step 3 exam!
Disclaimer: We did our absolute best to make sure everything is accurate and double checked everything but as with anything done by a human there is still potential for mistakes so if you find anything, please let us know by emailing us at info@thematchguy.com
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