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USMLE Step 2 CK High-Yield Respiratory Topics
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Respiratory
High Yield USMLE Step 2 CK Notes
Welcome to the Respiratory High-Yield Notes for Step 2 CK.
These are the most commonly tested topics on the exam—ideal for quick review in your last 2 weeks before the exam, when you’re short on time, or when you’re just starting out and want to focus on what is high yield. Created and peer-reviewed by physicians who scored 260+ on Step 2 CK in a Q&A style to reinforce active learning.
How to use this file
- Read the question ➔ cover the answer ➔ self-quiz before revealing.
- Review the NOTES ➔ they include high-yield details you don’t want to miss.
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- Don’t forget to watch the video lessons that go with this file. Learn more here.
Table of Contents
Pulmonary Infections & Inflammations
1. A 6-year-old child presents with rhinorrhea, low-grade fever, nasal congestion, and bilateral cervical lymphadenopathy. Symptoms have lasted 3 days. What is the next step?
➔ Supportive care only (Nasal congestion + rhinorrhea + ≤3 days + low-grade fever → Think viral rhinosinusitis → needs supportive treatment)
- Note: Don’t give → antibiotics unless bacterial signs develop
Differentiation Notes:
| Condition | Clue |
|---|---|
| Viral rhinosinusitis | <10 days; improving; low-grade fever |
| Bacterial sinusitis | >10 days; worsening; high fever |
| Allergic rhinitis | Sneezing; itchy eyes; no fever |
2. A 7-year-old child has had nasal congestion and cough for 12 days that worsened after initial improvement. He now has facial pain, purulent nasal discharge, and fever of 39.5°C. What is the next step?
➔ Start antibiotics (Amoxicillin-clavulanate) (Symptoms suggestive of Acute Bacterial Rhinosinusitis)
- Note: Diagnosis requires ≥1 of the following:
○ Symptoms >10 days without improvement
○ Severe onset: Fever ≥39°C + purulent discharge ≥3 days
○ Worsening after initial improvement - Nasogastric tube placement in hospitalized patient → leads to impaired sinus drainage → leads to ↑ risk of secondary bacterial sinusitis
3. A 5-month-old infant presents with nasal congestion, cough, wheezing, and increased work of breathing. The exam shows crackles. What is the diagnosis?
➔ Bronchiolitis (Child <2 years + viral URI + cough + wheezing → think Bronchiolitis)
- Note: Most common cause is → RSV
- Manage by → Supportive care only (no antivirals/antibiotics)
Differentiate bronchiolitis from asthma by age <2 years with viral URI (RSV) vs. recurrent wheezing in older children with atopy and bronchodilator response.
4. A 25-year-old woman presents in October for a routine visit. She has no chronic illness. What is the next step in management?
➔ Administer annual influenza vaccination
- Note: Everyone ≥6 months gets it annually
- Types:
○ Inactivated IM: safe for all (including pregnancy)
○ Live attenuated intranasal: age 2–49, avoid in immunocompromised - Watch for rapid worsening or new symptoms → Possible secondary bacterial pneumonia (esp. S. aureus)
5. A 42-year-old woman presents with a persistent dry cough for 10 weeks. She denies fever or weight loss. The exam is normal. Chest X-ray is clear. She has no smoking history. What is the next step in management?
➔ Empiric trial of antihistamine for postnasal drip (upper airway cough syndrome) (Chronic cough + normal exam + clear CXR → Most common cause is postnasal drip → start empiric treatment)
- Note: Chronic Cough → is coughing >8 weeks
- If normal exam + clear CXR, consider:
○ Postnasal drip → 1st-gen antihistamine
○ GERD → PPI trial
○ Asthma → bronchodilator trial or methacholine challenge
○ ACE inhibitor → discontinue med
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6. A 45-year-old man presents with fever, productive cough, pleuritic chest pain, and right lower lobe infiltrate on CXR. What is the diagnosis?
➔ Community-acquired pneumonia (CAP) (lobar infiltrate → think typical bacterial cause of pneumonia)
- Note: Common typical pathogens include → S. pneumoniae, H. influenzae, M. catarrhalis
- If recurrent pneumonia in the same lobe → think bronchial obstruction (tumor or foreign body)
Differential: Lobar vs. Interstitial Pneumonia
| Feature | Lobar Pneumonia | Interstitial Pneumonia |
|---|---|---|
| Presentation | Sudden onset; high fever; productive cough; focal signs | Gradual onset; low/absent fever; dry cough; diffuse crackles |
| CXR | Lobar consolidation (single lobe) | Diffuse/reticulonodular infiltrates |
| Pathogens | S. pneumoniae; H. influenzae | Mycoplasma; Chlamydia; viruses |
7. A 45-year-old man with a productive cough, fever, and right lower lobe infiltrate on CXR has no comorbidities. His vitals are stable and the patient is fully conscious. What is the next step in management?
➔ Outpatient treatment with oral amoxicillin + azithromycin (Symptoms suggest Low-risk Community-acquired pneumonia (CURB-65 = 0))
- Note: CAP management is based on CURB-65 Score (1 point each):
- Confusion
- Urea > 7 mmol/L (BUN > 20 mg/dL)
- Respiratory rate ≥ 30
- Blood pressure < 90 systolic or ≤ 60 diastolic
- Age ≥ 65 years
| CURB-65 Score | Clinical Decision | Antibiotic Treatment |
|---|---|---|
| 0–1 | Outpatient | β-lactam + Macrolide or Doxycycline |
| 2 | Inpatient (ward) | IV (β-lactam + Macrolide) or IV Fluoroquinolone |
| ≥3 | Inpatient (consider ICU) | IV (β-lactam + Macrolide) or IV (β-lactam + Fluoroquinolone) |
8. A 9-year-old child presents with 2 weeks of severe coughing fits followed by vomiting. His younger sibling recently had a mild cold. What is the diagnosis?
➔ Pertussis (Paroxysmal cough + posttussive vomiting + lymphocytosis → Think Pertussis)
- Note: Symptoms may include posttussive cyanosis, apnea, rib fractures, syncope
○ Coughing fits are often worse at night + can wake patient from sleep - Confirm with → PCR or culture from nasopharyngeal swab
9. A 9-year-old boy is diagnosed with pertussis after presenting with 2 weeks of severe coughing fits and posttussive vomiting. What is the next step to manage the patient and prevent transmission?
➔ Start azithromycin and treat close contacts
- Note: Treatment → Macrolides (e.g., azithromycin) + Treat close contacts as well
- Prevented by → DTaP/Tdap vaccine (acellular pertussis)
10. A 76-year-old man with dementia is hospitalized for a stroke and has new-onset oropharyngeal dysphagia. What interventions can help reduce his risk of aspiration pneumonia?
➔ Head elevation, swallowing evaluation, and oral hygiene
- Note: Stroke, dysphagia, AMS, poor oral hygiene → ↑ aspiration risk
- Preventive strategies to ↓ aspiration risk:
○ Elevate head of bed ≥30° at all times
○ Swallowing evaluation before initiating oral intake (esp. in stroke)
○ Optimize oral hygiene → ↓ oral flora burden
○ Avoid/minimize sedatives
11. A 72-year-old nursing home resident presents with fever, cough product of foul-smelling sputum, and a right lower lobe infiltrate. What is the empiric treatment?
➔ Standard CAP treatment (Patient with risk factors + fever + foul-smelling sputum + RLL infiltrate → Think Aspiration pneumonia → treat per standard CAP guidelines, NOT empiric anaerobic coverage)
- Note: Aspiration pneumonia does not require anaerobic coverage unless complicated by abscess or empyema; in that case, use Ampicillin-sulbactam; if beta-lactam allergy, use Clindamycin
- Cause: Inhalation of orogastric contents ± anaerobic bacteria
- Differentiate from → aspiration pneumonitis, which presents post-emesis but with no signs of infection
12. A 70-year-old man is found unresponsive after alcohol intoxication. Hours later, he develops hypoxia and bilateral infiltrates on CXR. No fever or foul sputum. What is the next step?
➔ Supportive care only (Acute onset hypoxia + recent vomiting + no fever or sputum → Think Aspiration pneumonitis → only supportive treatment)
- Note: Caused by → chemical injury to lungs from gastric acid (not infection)
13. A 46-year-old man with a history of alcohol use presents with fever, productive cough with foul-smelling sputum, and weight loss. CXR shows a cavitary lesion with air-fluid level in the right lung. What is the next step in management?
➔ Start IV clindamycin (Alcoholic + foul sputum + cavitary lesion → Lung abscess → Treat with anaerobic coverage)
- Note: Cavity with air-fluid level (commonly in dependent lung segments) → is a Key finding
- Treatment:
○ IV antibiotics:
■ Clindamycin (anaerobic coverage)
■ OR Ampicillin-sulbactam
○ Drainage rarely needed unless large/refractory
14. A 55-year-old smoker presents with weight loss, dry cough, and unilateral pleural effusion. Thoracentesis shows high protein and elevated LDH. What is the cause?
➔ Malignancy-related exudative effusion (Unilateral effusion + weight loss + smoker → Think malignancy)
- Note: There are two types of effusions (exudative and transudative) → differentiated based on Light Criteria
- Light’s Criteria for Exudate effusion (only 1 needed):
○ Pleural/serum protein > 0.5
○ Pleural/serum LDH > 0.6
○ Pleural LDH > ⅔ ULN
Differentiation Notes
| Effusion Type | Key Features | Common Causes |
|---|---|---|
| Transudate | Usually bilateral, clear, low protein | CHF, cirrhosis, nephrotic syndrome |
| Exudate | Usually unilateral, ↑ protein/LDH | Infection, malignancy, PE, autoimmune |
15. A 67-year-old man with CHF presents with dyspnea. CXR shows bilateral pleural effusions. Thoracentesis reveals clear fluid with low protein and LDH. What is the next step in management?
➔ Administer IV furosemide (Transudative pleural effusion due to CHF → treat with Diuretics (e.g., furosemide))
- Note: Management:
○ Treat underlying cause (e.g., diuretics for CHF)
○ If small + asymptomatic pleural effusion → no intervention needed
16. A 60-year-old immunosuppressed man presents with fever, cough, and dyspnea. Imaging reveals a loculated pleural fluid collection with heterogeneous density and reduced lung volumes. Thoracentesis yields frank pus. What is the next step in management?
➔ Chest tube placement with drainage and antibiotics (fever + cough + loculated pleural fluid + pus → think empyema)
- Note: Confirmed with Thoracentesis → shows frank pus or positive culture
- Treatment:
○ Initial: Chest tube drainage (source control)
○ Antibiotics: Empiric → then target based on culture
Differential Diagnosis Table
| Condition | Key Thoracentesis Findings |
|---|---|
| Empyema | pH < 7.2, glucose < 60 mg/dL, purulent fluid, positive Gram stain/culture |
| Simple exudative effusion | pH > 7.2, normal glucose (usually > 60 mg/dL), no organisms on culture |
17. A 58-year-old man develops fever, chest pain, and purulent sternal wound drainage 3 days after coronary artery bypass grafting. Chest x-ray shows mediastinal widening. What is the next step in management?
➔ Surgical debridement with IV broad-spectrum antibiotics (Post-op + fever + chest pain + mediastinal widening →Think Acute Mediastinitis → Urgent surgery + antibiotics)
- Note: Caused by → Post-sternotomy infection
- Next Step → Immediate surgical debridement + IV broad-spectrum antibiotics
18. A 35-year-old man recently immigrated from India and has no symptoms. His screening PPD test shows a 14 mm induration. What is the next best step?
➔ Chest X-ray (Positive PPD in an at-risk patient → Next step is to rule out active TB by CXR)
- Note: PPD ≥10 mm in recent immigrants indicates → positive result
- Next step: CXR to check for active TB
○ If CXR normal → Treat latent TB (e.g., isoniazid + B6 for 9 months)
○ If CXR shows cavitation or infiltrate → Do sputum AFB to confirm active TB
PPD Cutoffs
| PPD Size | Positive in |
|---|---|
| ≥5 mm | HIV+, recent TB contacts, immunosuppressed (e.g., transplant, steroids), abnormal CXR (old TB) |
| ≥10 mm | Recent immigrants, healthcare workers, IV drug users, CKD, DM, children <4 yrs, exposed to high-risk adults |
| ≥15 mm | Healthy, low-risk individuals |
19. A 42-year-old man with HIV presents with cough, weight loss, night sweats, and hemoptysis. CXR shows apical cavitary lesions. What is the diagnosis?
➔ Active Pulmonary Tuberculosis (Patient with risk factors + hemoptysis + apical cavitary lesions → Think active TB)
- Note: Seen in immunosuppressed (eg. HIV) or Immigrants
- Since CXR shows → cavitation or infiltrate → next step → Do sputum AFB to confirm active TB
- Treatment:
○ RIPE: Rifampin, Isonazid, Pyrazinamide, Ethambutol
○ Airborne isolation until non-infectious
20. A 22-year-old college student presents with dry cough, low-grade fever, and malaise. The exam shows diffuse crackles, but CXR is normal. He also reports mild sore throat and fatigue. What is the next step in management?
➔ Treat with Azithromycin (Young adults+ dry cough + normal CXR + pharyngitis → Think Mycoplasma pneumoniae)
- Note: Associated findings:
○ Nonexudative pharyngitis
○ Maculopapular rash
○ Hemolytic anemia (due to cold agglutinins) - Treat with → Macrolide (azithromycin) or doxycycline
21. A 32-year-old man with HIV with CD4+ count 90/mm³ presents with fever, dry cough, and worsening dyspnea on exertion. CXR shows bilateral interstitial infiltrates. PaO₂ is 64 mm Hg. What is the next step in management?
➔ Start IV TMP-SMX and corticosteroids (Immunosuppression + hypoxia + bilateral infiltrates → Think Pneumocystis jirovecii pneumonia)
- Note: Confirmed with → Bronchoalveolar lavage with silver stain
- Treatment:
○ First-line: TMP-SMX (IV for severe, PO for mild)
○ Add steroids if PaO₂ <70 or A-a gradient >35 - Prophylaxis → TMP-SMX if CD4+ <200/mm³
22. A 24-year-old woman with a history of asthma presents with worsening cough, wheezing, low-grade fever, and brown sputum production. Labs show eosinophilia and elevated total serum IgE. Chest CT shows central bronchiectasis. What is the diagnosis?
➔ Allergic bronchopulmonary aspergillosis (ABPA) (Worsening asthma + brownish sputum + low-grade fever + eosinophilia + ↑IgE + bronchiectasis → Think ABPA)
- Note: Risk group: Asthma, cystic fibrosis
- Treat with → Systemic corticosteroids → if recurrent or severe → Add itraconazole or voriconazole
23. A 50-year-old man with a history of prior TB presents with cough, hemoptysis, and weight loss. CXR shows a cavitary lesion with a mobile mass and an air crescent. What is the diagnosis?
➔ Aspergilloma (Chronic cavitary lesion + mobile intracavitary mass + hemoptysis → Think Aspergilloma)
- Note: Caused by colonization of a preexisting lung cavity (e.g., TB, sarcoidosis) by Aspergillus
- Imaging shows → Cavitary lesion with mobile intracavitary mass
- Treatment:
○ Asymptomatic or mild hemoptysis → Observe only
○ Recurrent or massive hemoptysis → Surgical resection
24. A 9-year-old boy has recurrent pneumonia, foul-smelling stools, and digital clubbing. What is the next step to confirm the diagnosis?
➔ Perform sweat chloride test (Recurrent pneumonia + steatorrhea + clubbing → Think Cystic Fibrosis → Confirm with sweat chloride test )
25. A 35-year-old African American woman presents with dry cough, and blurry vision. Chest x-ray shows bilateral hilar lymphadenopathy. Biopsy reveals non-caseating granulomas. What is the next step in management?
➔ Start oral corticosteroids (African American + dry cough + uveitis + bilateral hilar lymphadenopathy → Think Sarcoidosis)
- Note: Confirms diagnosis with → Biopsy → shows non-caseating granulomas
- Treatment:
○ Asymptomatic: Observe only
○ Symptomatic: Oral corticosteroids
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Obstructive Lung Diseases
26. A 19-year-old male with 1-year smoking history presents with progressive dyspnea, ↓ breath sounds, and ↑ AP chest diameter. CXR shows hyperinflation with bibasilar lucency. What is the diagnosis?
➔ Alpha-1 Antitrypsin (AAT) Deficiency (Early-onset COPD (<45) + basilar emphysema + liver dysfunction → Think Alpha-1 Antitrypsin Deficiency)
- Note: Diagnosed by → ↓ serum AAT level → confirmed with → genetic testing
- Treatment: Smoking cessation, AAT replacement, bronchodilators, O₂
Differentiate AAT deficiency from typical smoking-related COPD by age of onset and presence of liver dysfunction.
27. A 17-year-old girl with a history of recurrent pneumonia since childhood presents with chronic productive cough and pleuritic chest pain. Chest CT confirms bronchiectasis. What is the most appropriate next step in management?
➔ Chest physiotherapy with airway clearance and empiric antibiotics (Symptoms suggestive of Bronchiectasis)
- Note: Chest CT shows → bronchial dilation, tram-track or signet ring signs
- Treatment: Chest physiotherapy, antibiotics, treat underlying cause
28. A 26-year-old woman presents with recurrent episodes of chest tightness, wheezing, and shortness of breath. Pulmonary function testing shows ↓ FEV₁. FEV₁ increases by 15% after bronchodilator use. What is the diagnosis?
➔ Asthma (Obstructive pattern + reversible airflow limitation → Think asthma)
- Note: Asthma Diagnosis by PFTs:
○ Obstructive pattern: ↓ FEV₁, ↓ FEV₁/FVC, ↑ TLC (air trapping)
○ Reversibility confirms asthma:
○ ↑ FEV₁ ≥12% with bronchodilator (e.g., albuterol)
○ OR ↓ FEV₁ ≥20% with methacholine challenge
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29. A 14-year-old girl has daytime asthma symptoms 4 days per week and nighttime cough twice per month. She uses her albuterol inhaler as needed. What is the next step?
➔ Start a daily low-dose inhaled corticosteroid (ICS) (Mild persistent asthma = >2 days/week + ≤1 night/week → Start low-dose ICS)
- Note: Management by Severity
| Severity | Symptoms | Management |
|---|---|---|
| Intermittent | ≤2 days/week, ≤2 nights/month | SABA as needed |
| Mild Persistent | >2 days/week, ≤1 night/week | Low-dose ICS + SABA PRN |
| Moderate Persistent | Daily symptoms, >1 night/week | Low-dose ICS + LABA or med-dose ICS |
| Severe Persistent | Continuous symptoms, frequent nighttime | High-dose ICS + LABA ± oral steroids |
30. A 17-year-old boy with asthma presents with SOB, wheezing, and PEF <40% of baseline. He has used albuterol with no relief. SpO₂ is 88%. What is the next best step?
➔ Inhaled albuterol + ipratropium + systemic corticosteroids (Symptoms suggestive of severe asthma exacerbation)
- Note: Acute asthma exacerbation management:
○ SABA (albuterol): first-line
○ + Ipratropium: for moderate/severe
○ + Systemic steroids: oral/IV (e.g., prednisone)
○ O₂: if SpO₂ < 90%
○ Intubate if AMS or rising CO₂
31. A 34-year-old woman with asthma and nasal polyps develops wheezing and nasal congestion after taking ibuprofen. What is the next step?
➔ Avoid NSAIDs (Asthma + nasal polyps + NSAID reaction → Think Aspirin-exacerbated respiratory disease)
- Note: Avoid NSAIDs and do surgery for polyps if needed
32. A 15-year-old girl using daily inhaled corticosteroids and frequent albuterol presents for follow-up. What side effects should be monitored?
➔ Oral candidiasis (ICS) and tremor/tachycardia (albuterol) (ICS and SABA have predictable adverse effects → monitor and prevent)
- Note: ICS can cause → Oral thrush → prevent by using spacer + mouth rinse
- SABA (e.g., albuterol) can cause → Tremor, tachycardia, hypokalemia (dose-dependent)
33. A 60-year-old man with chronic cough and exertional dyspnea is diagnosed with moderate COPD (FEV1 55%). What is the most important intervention to slow disease progression?
➔ Smoking cessation (Most effective intervention → slows decline in FEV1)
- Note: Severity of disease is based on FEV1 (% predicted)
- Chronic hypoxia can lead to → Pulmonary HTN
34. A 64-year-old man with moderate COPD presents with chronic cough and dyspnea on exertion. He is compliant with short-acting bronchodilators but continues to have daily symptoms. What is the next step in management?
➔ Add a long-acting bronchodilator (LABA or LAMA) (Persistent COPD symptoms despite SABA → step up to long-acting bronchodilators)
- Note: Stepwise COPD Treatment:
○ SABA or SAMA PRN (initial step)
○ Add LABA or LAMA for persistent symptoms
○ ICS if frequent exacerbations
35. A 68-year-old man with moderate COPD reports increasing fatigue and limited ability to walk due to breathlessness. He is on optimal inhaler therapy. What intervention would most improve his quality of life?
➔ Enroll in pulmonary rehabilitation (Persistent functional limitation despite medical therapy → Pulmonary rehab improves exercise tolerance & quality of life)
- Note: Combine with → Smoking cessation (slows progression)
→ Vaccinations: annual Influenza + pneumococcal
36. A 67-year-old man with a 30-pack-year smoking history and recently diagnosed COPD presents for routine care. He received the influenza vaccine last month. What is the most appropriate pneumococcal vaccination strategy?
➔ Administer PCV20 now or PCV15 now followed by PPSV23 in 1 year
Pneumococcal Vaccine in COPD
| Patient | What to Give |
|---|---|
| Healthy (or COPD) + Age ≥50 | PCV20/21 once OR PCV15 now + PPSV23 in 1 yr |
| COPD + Age <50 | PCV20/21 once OR PCV15 now + PPSV23 in 1 yr |
| Healthy Adult + no risk factors + Age <50 | Not indicated till Age 50 |
37. A 68-year-old man with severe COPD presents with dyspnea, cough, and confusion. ABG shows pH 7.26, PaCO₂ 68 mm Hg. What is the cause of his mental status change?
➔ Acute hypercapnia from COPD exacerbation (ABG shows → ↑ PaCO₂, respiratory acidosis ± hypoxemia)
- Note: Triggered by → Infection
- Target SpO₂ is → 88–92% → To avoid CO₂ retention
38. A 72-year-old man with severe COPD presents with dyspnea, confusion, and use of accessory muscles. ABG reveals pH 7.28, PaCO₂ 64 mm Hg, and PaO₂ 58 mm Hg. What is the next step in management?
➔ Initiate noninvasive positive pressure ventilation (BiPAP) (COPD exacerbation + hypercapnia + AMS → Indication for BiPAP)
- Note: Stepwise COPD exacerbation treatment:
○ Bronchodilators: Albuterol + ipratropium (neb)
○ Systemic steroids: Oral prednisone or IV methylprednisolone
○ Antibiotics if If ↑ sputum purulence/volume
○ Noninvasive ventilation (BiPAP): If AMS or ↑CO₂
○ Intubation: If BiPAP fails or the patient is obtunded.
Pulmonary Neoplasms
39. A 66-year-old man with a 40 pack-year smoking history and no current symptoms presents for a routine check-up. He quit smoking 5 years ago. What is the next best step in management?
➔ Annual low-dose chest CT (Meets criteria for lung cancer screening)
- Note: Screen with low-dose CT annually if:
Age 50–80 + ≥20 pack-year smoking history + Currently smoking or quit within past 15 years
40. A 58-year-old man with a 40-pack-year smoking history presents with his third episode of pneumonia in the right lower lobe within the past year. What is the next step in evaluation?
➔ CT chest (Recurrent pneumonia in the same location → think obstructing mass)
- Note: If CT suggests mass or FB → Do Bronchoscopy
- Common causes:
○ Bronchogenic carcinoma (especially in smokers)
○ Foreign body (esp. in children or elderly)
41. A 66-year-old man with a 40 pack-year smoking history presents with weight loss, cough, and recurrent pneumonia. CXR shows right lower lobe atelectasis. What is the cause?
➔ Lung cancer (weight loss + chronic cough + recurrent pneumonia in the same location → Think obstructing central tumor)
- Note: Lung cancer is the second most common type of cancer and the leading cause of cancer-related deaths
- Compare with → Recurrent pneumonia in different lobes → Think immunodeficiency, ciliary dyskinesia, aspiration
42. A 66-year-old man with a 45 pack-year smoking history presents with weight loss, cough, and hemoptysis. CXR reveals a hilar mass and right lower lobe collapse. Labs show hypercalcemia. What is the diagnosis?
➔ Squamous Cell Carcinoma of the Lung (Hemoptysis + hilar mass + smoking + hypercalcemia → Think squamous cell carcinoma)
- Note: Squamous cell carcinoma location is central and strongly associated with smoking
- Associated with PTHrP secretion → leads to hypercalcemia
Lung Cancer Differential Table
| Type | Location | Paraneoplastic Features | Key Differentiators |
|---|---|---|---|
| SCC (Squamous) | Central | PTHrP → Hypercalcemia | Smoking, cavitary lesion, keratin pearls |
| Adenocarcinoma | Peripheral | None common (can rarely produce hormones) | Most common overall, esp. in nonsmokers |
| Small Cell Carcinoma | Central | ACTH, SIADH, Lambert-Eaton syndrome | Aggressive, neuroendocrine markers, rapid progression |
43. A 62-year-old smoker presents with right shoulder pain, ptosis, miosis, and facial swelling. CXR shows a right apical mass. What is the diagnosis?
➔ Pancoast tumor (Smoker + shoulder pain + Horner syndrome + apical mass → Think Pancoast Tumor)
- Note: Imaging: CXR or CT → Apical, rounded mass → then bronchoscopy or CT guided biopsy
Differentiation Pancoast tumor from SVC syndrome (Both are complications of apical lung tumors):
○ Pancoast causes Horner syndrome and arm weakness from brachial plexus invasion → while SVC syndrome causes facial swelling and JVD due to venous compression.
44. A 64-year-old man with a 40-pack-year smoking history and daily alcohol use presents with a non-healing painless ulcer on the lateral tongue and a firm cervical lymph node. What is the next step in management?
➔ Perform flexible laryngoscopy (Persistent oral lesion + cervical LAD +/- hoarseness or dysphagia → Evaluate for HNSCC)
- Note: Smoking, alcohol, HPV (especially oropharynx) → increase the risk
- Diagnosed by → Flexible laryngoscopy
○ Then: Biopsy or FNA of neck mass
45. A 66-year-old retired shipyard worker presents with progressive dyspnea, dry cough, digital clubbing, and bibasilar crackles. CXR shows bilateral lower lobe reticulonodular opacities and pleural plaques. What is this patient most at risk of developing?
➔ Bronchogenic carcinoma (pleural plaques + lower lobe fibrosis → Think Asbestosis → ↑ risk of bronchogenic carcinoma)
- Note: Risks for Asbestos exposure → shipyard, insulation, plumbing
- Complications:
○ ↑ Risk of bronchogenic carcinoma (most common)
○ ↑ Risk of mesothelioma (rarer but classically linked)
Trauma & Airway Emergencies
46. A 2-year-old boy presents with sudden-onset cough and wheezing. Breath sounds are decreased on the right, and CXR shows right lung hyperinflation. Albuterol has no effect. What is the next best step in management?
➔ Rigid bronchoscopy (Sudden cough + unilateral findings + no response to albuterol → Think foreign body aspiration)
- Note: Age group: Toddlers (1–3 years)
Differentiation Notes
| Condition | Clue |
|---|---|
| Foreign body aspiration | Sudden-onset wheeze, unilateral ↓ air, No improvement with albuterol |
| Asthma | Bilateral wheeze, chronic pattern, Improves with bronchodilators |
| Bronchiolitis | Infant with URI + wheezing, Viral prodrome, bilateral findings |
47. A 35-year-old man is rescued from a house fire. He has facial burns, hoarseness, and carbonaceous sputum. What is the next step in management?
➔ Endotracheal intubation (Facial burns + hoarseness + carbonaceous sputum → Think airway injury → Intubate early)
- Note: Superheated air → leads to airway edema & obstruction
- Next step → Immediate endotracheal intubation (before airway closes)
○ Don’t delay for imaging or labs
48. A 30-year-old man is found unconscious in his garage with the car running. He has a headache and confusion. Pulse oximetry reads 99%. What is the next step in management?
➔ Administer 100% oxygen (Confusion + headache + normal SpO₂ + enclosed space → Think CO poisoning)
- Note: Treatment:
○ 100% O₂ via non-rebreather mask
○ Hyperbaric O₂ if severe (e.g., coma, cardiac ischemia)
Differentiation Notes
| Condition | Clue | How to Differentiate |
|---|---|---|
| CO poisoning | Exposure + headache, confusion | Normal pulse ox, ↑ lactate, cherry-red skin |
| Cyanide poisoning | Fire victim + hypotension, almond smell | Also causes lactic acidosis, treat prophylactically with thiosulfate or hydroxycobalamin |
49. A 42-year-old mechanic with daily exposure to car exhaust presents with headache, dizziness, fatigue, and exertional chest pain. His SpO₂ is 98%, but ECG shows T-wave inversions. What is the cause?
➔ Chronic carbon monoxide poisoning (Chronic exposure + nonspecific symptoms + normal SpO₂ → Think chronic CO poisoning)
- Note: CO poisoning can cause MI in both acute and chronic cases
- Treated with → 100% oxygen ± remove source
50. A 65-year-old obese man with COPD undergoes abdominal surgery. Post-op, he develops dyspnea, somnolence, and ABG shows hypoxemia and hypercapnia. What is the next step in management?
➔ Endotracheal intubation and mechanical ventilation (COPD + obesity + post-op + hypercapnic respiratory failure → suggest Perioperative Respiratory Failure → Intubate)
- Note: Mechanism includes → diaphragmatic dysfunction, splinting, pain → leading to hypoventilation
- Management:
○ Immediate: CPAP or BiPAP → improves oxygenation, ↓ work of breathing
○ Immediate intubation if signs of respiratory failure
Differentiate post-op respiratory failure from atelectasis by the presence of hypercapnia requiring ventilation vs. isolated hypoxemia and decreased breath sounds within 24–48 hours.
51. A 68-year-old man develops fever, mild dyspnea, and ↓ breath sounds in the right lower lung 24 hours after abdominal surgery. CXR shows lung opacity, loss of volume. ABG shows hypoxemia with normal PaCO₂. What is the cause?
➔ Postoperative atelectasis (Post-op day 1–2 + fever + ↓ breath sounds + hypoxemia without hypercapnia → Think Atelectasis)
- Note: ↓ Ventilation (e.g., pain, splinting, shallow breaths) → leads to airway collapse atelectasis
- Management: Incentive spirometry, early ambulation, adequate pain control
52. A 56-year-old man develops sudden hypotension and tracheal deviation after central line placement. Breath sounds are absent on the right, and the chest is hyperresonant. What is the next best step in management?
➔ Immediate needle decompression of the right chest (Sudden respiratory distress + hypotension + absent breath sounds + tracheal deviation → Tension Pneumothorax)
- Note: Diagnosis: Clinical — do not delay for CXR in unstable patient
- Managed with Emergency needle decompression (2nd intercostal space, midclavicular line)
○ Then place chest tube (tube thoracostomy)
53. A 25-year-old man presents to the ED after a stab wound to the left chest. He is hypotensive, tachycardic, and has decreased breath sounds with dullness to percussion on the left side. What is the most appropriate next step in management?
➔ Tube thoracostomy (chest tube insertion) (Chest trauma + ↓ breath sounds + dullness to percussion + hypotension → Think hemothorax → Insert chest tube)
- Note: First step in highly suspicious case → chest tube, both diagnostic & therapeutic:
○ Do NOT delay chest tube for imaging - Urgent thoracotomy if: >1500 mL initial output or >200 mL/hr bleeding
- Resuscitate with IV fluids + PRBCs if unstable
Salim S, more on site, PMC2567296 1757-1626-1-225-2, CC BY 2.0
54. A 25-year-old man presents after a motor vehicle accident. He has left-sided chest wall bruising, dyspnea, and hypoxia. Chest x-ray shows patchy alveolar opacities on the left side. What is the next step in management?
➔ Supportive care (Blunt trauma + patchy infiltrates + hypoxia → Pulmonary Contusion → Supportive care)
Differential Tip:
| Condition | Imaging Clue |
|---|---|
| Pulmonary Contusion | Patchy alveolar opacities near trauma |
| Hemothorax | Fluid level on CXR/US |
55. A 60-year-old woman develops acute dyspnea, hypoxia, and fever 2 hours after receiving packed RBCs and plasma. CXR shows bilateral pulmonary infiltrates. What is the next step in management?
➔ Supportive care with oxygen and respiratory support (Acute hypoxia + bilateral infiltrates <6 hrs post-transfusion → TRALI)
- Note: Management:
○ Stop transfusion
○ Supportive: Oxygen ± ventilation
High-Yield Differential: Transfusion-Related Acute Lung Injury vs Transfusion Associated Cardiac Overload
| Feature | TRALI | TACO |
|---|---|---|
| Onset | < 6 hours post-transfusion | < 6 hours post-transfusion |
| Mechanism | Neutrophil-mediated capillary leak | Volume overload |
| CXR | Bilateral infiltrates (non-cardiogenic) | Bilateral infiltrates + cardiomegaly |
| Neck veins/BP | Normal JVP, hypotension possible | Elevated JVP, hypertension |
56. A 7-year-old girl is rescued from a swimming pool after a brief submersion. She is alert but has a mild cough and appears fatigued. Vitals are stable. What is the next step in management?
➔ Hospital admission for observation (Post-drowning + mild symptoms → risk of delayed ARDS → observe)
- Note: Risk of ARDS due to alveolar inflammation & edema
- Monitor for ARDS (can develop up to 24 hrs post-incident)
57. A 32-year-old man presents with confusion, ataxia, and shortness of breath shortly after a rapid ascent during a recreational scuba dive. What is the diagnosis?
➔ Decompression Sickness (“The Bends”) (Neuro + respiratory + MSK symptoms after rapid ascent → Think DCS)
- Note: Rapid ascent → leads to nitrogen bubbles in blood/tissues → Decompression Sickness
- Treatment: 100% oxygen, IV fluids + Emergency hyperbaric oxygen therapy
Differential table
| Condition | Key Features | Clues to Differentiate |
|---|---|---|
| Decompression sickness | Neuro + pulm + joint symptoms after diving ascent | recent SCUBA dive |
| Fat embolism | Respiratory distress + petechiae + neuro symptoms | Long bone fracture, 12–72 hrs delay, petechiae |
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Pulmonary Vascular Disorders
58. A 58-year-old man with colon cancer presents 6 days post-op with sudden dyspnea, tachycardia, and pleuritic chest pain. What is the next step in management?
➔ CT pulmonary angiography (Recent surgery + cancer + sudden dyspnea/pleuritic pain → Think Pulmonary embolism→ Confirm with CTA)
- Note: CT pulmonary angiography is gold standard for diagnosis
○ If contrast contraindicated → do V/Q scan - Treatment:
○ Anticoagulation (eg. LMWH, heparin)
○ Thrombolysis if unstable (eg. syncope, hypotension)
59. A 68-year-old man with COPD presents with worsening dyspnea, leg swelling, and elevated JVP. He has a loud P2 and PaO₂ of 45 mm Hg. What is the next step in management?
➔ Supplemental oxygen therapy (COPD + hypoxia + signs of RHF → Cor pulmonale → Give oxygen)
- Note: Chronic hypoxia → leads to pulmonary vasoconstriction → Pulmonary HTN → Right HF
- Confirm Diagnosis with → Echo → shows RV strain
- Treat the underlying cause (COPD)
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Other Respiratory Disorders
60. A 65-year-old man with progressive exertional dyspnea and dry cough has inspiratory crackles on exam. Chest imaging shows peripheral, basilar honeycombing. What is the diagnosis?
➔ Idiopathic Pulmonary Fibrosis (IPF) (Progressive dyspnea + dry cough + basilar honeycombing → Think IPF)
- Note: High Resolution CT → shows basilar, peripheral reticular opacities + honeycombing
- Definitive diagnosis of the underlying cause → requires lung biopsy.
61. A 62-year-old man has progressive dyspnea. PFTs show FEV1/FVC = 80%, ↓ TLC, and ↓ DLCO. What is the diagnosis?
➔ Interstitial lung disease (Restrictive pattern + ↓ DLCO → Think ILD)
- Note: DLCO interpretation:
○ ↓ DLCO → ILD, emphysema
○ ↑ DLCO → Asthma
○ Normal DLCO → Chronic bronchitis, chest wall disorders
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62. A 34-year-old man hospitalized for pneumonia develops progressive hypoxemia despite high-flow O₂. CXR shows bilateral infiltrates with normal heart size. PaO₂/FiO₂ ratio is 180. What is the diagnosis?
➔ Acute Respiratory Distress Syndrome (ARDS) (ِAcute onset + bilateral infiltrates + PaO₂/FiO₂ ≤300 + no cardiomegaly → matches criteria for ARDS)
- Note: Cause: Direct (pneumonia, aspiration), Indirect (sepsis, trauma)
63. A 34-year-old man with ARDS is intubated due to refractory hypoxemia. What is the best ventilator strategy to improve survival?
➔ Low tidal volume mechanical ventilation (ARDS management → Lung-protective ventilation)
- Note: ARDS Treatment:
○ Low tidal volume mechanical ventilation (6 mL/kg)
○ PEEP to prevent alveolar collapse
○ Target SpO₂: 88–95%
○ Treat underlying cause (e.g., infection)
64. A 58-year-old man with ARDS is on mechanical ventilation. ABG shows pH 7.31, PaCO₂ 58 mm Hg, and PaO₂ 82 mm Hg (FiO₂ 50%, PEEP 8). What adjustment should be made?
➔ Increase respiratory rate (Hypercapnia → ↑ minute ventilation)
- Note: Oxygenation problem → ↑ FiO₂ or ↑ PEEP
- Ventilation (CO₂) problem → ↑ RR or ↑ TV (minute ventilation)
- Avoid excessive TV (>6–8 mL/kg) in ARDS (lung-protective)
65. A 54-year-old man with BMI 52 presents with somnolence and shallow breathing. ABG shows pH 7.31, PaCO₂ 55 mm Hg, PaO₂ 70 mm Hg, and a normal A–a gradient. What is the diagnosis?
➔ Obesity hypoventilation syndrome (Obesity + hypercapnia during the day + normal A–a gradient → Think Obesity hypoventilation syndrome)
- Note: Differentiate obesity hypoventilation from OSA by chronic daytime hypercapnia and abnormal ABG while awake, vs. OSA which shows normal daytime ABG with apneas during sleep.
66. A 48-year-old obese man presents with loud snoring, morning headaches, and excessive daytime sleepiness. Polysomnography confirms frequent episodes of apnea during sleep. What is the initial management?
➔ Initiate continuous positive airway pressure (CPAP) therapy (Obese + daytime sleepiness + apneic episodes → Think Obstructive Sleep Apnea → Start CPAP)
- Note: Polysomnography is gold standard for diagnosis
- Treatment:
○ First-line: CPAP during sleep
○ Weight loss, avoid alcohol/sedatives
○ Pediatric OSA → do Adenotonsillectomy (to relieve the obstruction)
Differentiate OSA from central sleep apnea by the presence of snoring and obstructive apneas on sleep study vs. central sleep apnea which shows Cheyne-Stokes breathing and association with heart failure or neurologic disease .
🏁 Final Thoughts
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Disclaimer
Version 1.0 August 2025. No part of this document may be reproduced or distributed without written permission. For personal study only. Medical information herein is for educational purposes and does not constitute clinical advice. Always confirm with current guidelines and your institution’s policies.
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