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USMLE Step 2 CK High-Yield Pediatrics Topics
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Pediatrics
High Yield USMLE Step 2 CK Notes
Welcome to the Pediatrics 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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Table of Contents
Infectious Diseases
1. A 6-year-old boy presents with honey-colored crusted lesions around his mouth. What is the most appropriate treatment?
➔ Topical mupirocin (Localized non-bullous impetigo → Treat with topical mupirocin)
- Note: Differentiate from:
○ Bullous impetigo → Larger flaccid bullae, usually caused by Staph aureus, lacks crusting early → Treat with → Oral cephalexin or dicloxacillin
○ HSV → Painful grouped vesicles on erythematous base → Forms ulcers, not honey-crusted.
2. A 3-month-old infant presents with a beefy red rash in the diaper area. The rash involves the skin folds and is associated with multiple satellite papules and pustules. What is the next step in management?
➔ Topical nystatin (Satellite lesions + skin fold involvement → Think Diaper candidiasis → treat with topical antifungal)
- Note: Avoid barrier creams alone (ineffective without antifungal)
- Differentiate from irritant diaper rash which spares folds and lacks satellite lesions → treat with → Topical barrier ointment
3. A 7-year-old boy presents with a scaly patch of hair loss on his scalp and cervical lymphadenopathy. The exam shows black dots within the patch and no boggy swelling. What is the best action to prevent transmission?
➔ Avoid sharing personal items such as hats and combs (Scaly alopecia patch + black dots + lymphadenopathy → Suggests tinea capitis)
- Note: Treat with → Oral antifungals (griseofulvin, terbinafine) → essential to eliminate infection and reduce spread
4. A 6-year-old girl presents with vulvar itching and erythema. There is no discharge or signs of trauma. What is the next step in management?
➔ Improve perineal hygiene and avoid irritants (Prepubertal vulvovaginitis without discharge or trauma → Think nonspecific irritation)
- Note: Causes: Poor hygiene, bubble baths, tight clothing, or occlusive underwear.
- Management: Cotton underwear, avoid irritants (soaps, baths), proper wiping front to back.
5. A 10-day-old infant has fever, poor feeding, and new-onset seizures. CSF shows lymphocytic pleocytosis, protein, low-normal glucose, and some RBCs. What is the diagnosis?
➔ Neonatal herpes simplex virus encephalitis (seizures + fever + CSF lymphocytes + RBCs in neonate → think HSV)
- Note: HSV encephalitis in neonates → leads to temporal lobe necrosis → RBCs in CSF
- Confirm with → PCR of CSF
- Start IV acyclovir immediately — don’t wait for PCR
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6. A 3-week-old infant presents with fever, lethargy, and poor feeding. On exam, he is irritable with a bulging fontanelle. CSF shows neutrophilic pleocytosis, low glucose, and elevated protein. What is the empiric treatment?
➔ Ampicillin + cefotaxime ± gentamicin (suspected bacterial meningitis in neonate → start empiric broad-spectrum antibiotics targeting common pathogens)
- Note: Neonatal bacterial meningitis → most commonly caused by: Group B Strep, E. coli, Listeria monocytogenes
| Age Group | Empiric Treatment | Key Pathogens |
|---|---|---|
| < 1 month | Ampicillin + cefotaxime ± gentamicin | GBS, E. coli, Listeria |
| 1 month – 50 years | Vancomycin + ceftriaxone | N. meningitidis, S. pneumoniae |
| > 50 years | Vancomycin + ceftriaxone + ampicillin | S. pneumoniae, N. meningitidis, Listeria |
7. A 2-day-old newborn presents with poor feeding, lethargy, and temperature instability. Physical exam reveals hypotonia and tachypnea. What is the diagnosis?
➔ Early-onset neonatal sepsis (<72 hrs + nonspecific symptoms like poor feeding & hypotonia → think perinatally acquired infection)
- Note: Common pathogens:
○ Group B Streptococcus (GBS) – most common
○ Escherichia coli – especially in preterm infants or those with galactosemia - Workup → CBC, blood/urine cultures, CXR, lumbar puncture.
- Treat with → Empiric antibiotics → ampicillin + gentamicin or cefotaxime.
8. A 2-day-old newborn is small for gestational age and has microcephaly, jaundice, hepatosplenomegaly, and petechiae. Head ultrasound shows periventricular calcifications. What is the diagnosis?
➔ Congenital CMV infection (Periventricular calcifications + sensorineural hearing loss+ Petechiae → Think CMV)
- Note: Primary maternal CMV infection → transplacental transmission
- Diagnosis is confirmed with viral culture or PCR from urine or blood
9. A 3-day-old newborn is small for gestational age and has chorioretinitis, hydrocephalus, and diffuse intracranial calcifications. What is the diagnosis?
➔ Congenital Toxoplasmosis (Diffuse intracranial calcifications + chorioretinitis + hydrocephalus → Think Toxoplasmosis)
- Note: Maternal exposure to cat feces or undercooked meat → transplacental transmission
- Treat with → Pyrimethamine + sulfadiazine + leucovorin
10. A 1-day-old newborn has a low birth weight, cataracts, sensorineural deafness, and a continuous machine-like murmur. What is the diagnosis?
➔ Congenital Rubella (Cataracts + deafness + PDA → Classic triad of Rubella)
- Note: Maternal infection in first trimester → transplacental transmission
- Prevent with → MMR vaccine (live attenuated, not during pregnancy)
11. A 6-month-old infant presents with recurrent oral thrush, otitis media, and pneumonia. Examination reveals cervical lymphadenopathy and hepatosplenomegaly. What is the next step to confirm the diagnosis?
➔ HIV PCR testing (HIV viral load) (Recurrent infections + lymphadenopathy + hepatosplenomegaly + growth retardation → Suggests perinatal HIV)
- Note: Vertical HIV: Acquired during delivery or breastfeeding, esp. if no maternal ART
- Differentiate from SCID → can mimic perinatal HIV with recurrent infections and failure to thrive, but lacks lymphadenopathy due to absent T/B cells and no lymphoid proliferation.
12. A 9-month-old infant presents with profuse watery, foul-smelling diarrhea and signs of dehydration. No blood is noted in the stool. What is the cause of this patient’s symptoms?
➔ Rotavirus (Watery diarrhea in infant + no blood + dehydration → Think Rotavirus)
- Note: Most common cause of infectious diarrhea in infants and young children worldwide
- Treatment → Supportive care with oral/IV rehydration
- Differentiate from diarrhea caused by Norovirus → older age, shorter illness, vomiting predominant
13. A 2-year-old child presents with high fever, cough, coryza, and conjunctivitis. Examination shows bluish-white spots on the buccal mucosa and a morbilliform rash spreading from the face downward. What is the next step in management?
➔ Supportive care + vitamin A (Fever + 3 C’s [cough, coryza, conjunctivitis] → Koplik spots → cephalocaudal rash spread → Suggests measles)
14. A 14-year-old unvaccinated boy presents with fever, bilateral cheek swelling, and jaw pain. Three days later, he developed testicular pain and swelling. What is the diagnosis?
➔ Mumps (Parotitis + orchitis in adolescent male → Think Mumps)
- Note: Complications → Orchitis, pancreatitis, aseptic meningitis
15. A 9-year-old boy with a history of sickle cell disease presents with fever and malaise. On exam, he is febrile and appears ill, but hemodynamically stable. Laboratory testing shows leukocytosis. What is the next step in management?
➔ Administer ceftriaxone (Fever + sickle cell disease → Think functional asplenia → Risk of overwhelming infection with encapsulated organisms → Immediate empiric antibiotics)
- Note: Ceftriaxone (or cefotaxime) provides broad coverage, especially against S. pneumoniae, H. influenzae, and N. meningitidis
16. A 3-year-old boy with sickle cell disease is brought for a routine visit. He has had no recent hospitalizations. What is the most effective strategy to prevent life-threatening infections in this patient?
➔ Pneumococcal vaccination and penicillin prophylaxis (Sickle cell → Leads to functional asplenia → High risk of sepsis → Requires vaccines + prophylactic antibiotics)
- Note: Key prevention:
○ Pneumococcal vaccination (PCV13 + PPSV23)
○ Penicillin (prophylaxis until age 5 or longer)
○ Also vaccinate against Haemophilus influenzae type B and Neisseria meningitidis
17. A 7-year-old boy with sickle cell disease presents with sudden-onset fatigue and pallor. Exam reveals conjunctival pallor without splenomegaly. Labs show severe anemia with very low reticulocyte count. What is the cause?
➔ Parvovirus B19 infection (Sudden severe anemia + ↓ retic count in sickle cell → Think aplastic crisis from Parvovirus B19)
- Note: Classic in sickle cell or hereditary spherocytosis
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Cardiology
18. A 10-year-old girl presents with fever, migratory joint pain, and a new holosystolic murmur best heard at the apex. Her history includes a sore throat 3 weeks ago that was not treated. A physical exam reveals a faint, pink, ring-shaped rash on her trunk. What is the diagnosis?
➔ Acute rheumatic fever (A post-streptococcal autoimmune reaction causing → molecular mimicry (M protein) → Leads to systemic inflammations)
- Note: Diagnosis: Jones criteria
○ Major: Polyarthritis, carditis (pancarditis), chorea, erythema marginatum, subcutaneous nodules
○ Minor: Fever, arthralgia, ↑ESR/CRP, prolonged PR
19. A 13-year-old girl with a history of acute rheumatic fever at age 9 presents for a routine visit. She had mild carditis at the time but no residual valvular disease on her last echocardiogram. What is the next step in management?
➔ Continue intramuscular benzathine penicillin G every 4 weeks (Prevents recurrence of rheumatic fever and progression of rheumatic heart disease)
- Note: Prophylaxis with → IM penicillin G benzathine every 4 weeks
- Duration depends on carditis:
○ No carditis: 5 years or until age 21
○ Carditis but no residual disease: 10 years or until age 21
○ Carditis + residual disease: 10 years or until age 40
20. A 6-year-old child with a history of a ventricular septal defect presents with exertional dyspnea, hepatomegaly, and clubbing. Vitals show oxygen saturation of 93% on room air. What is the explanation for these findings?
➔ Reversal of left-to-right shunt due to pulmonary hypertension (Long-standing VSD → ↑ pulmonary vascular resistance → Eisenmenger physiology)
- Note: VSD causes left-to-right shunt → ↑ pulmonary blood flow → vascular remodeling
- Chronic PVR ↑ → leads to right-sided hypertrophy and eventual shunt reversal
- Primary VSD symptoms before reversal are → dyspnea, tachypnea during feeding, cardiomegaly
21. A 4-month-old infant has episodes of bluish discoloration during crying and feeding. On exam, a harsh systolic murmur is heard over the left upper sternal border. What is the diagnosis?
➔ Tetralogy of Fallot (Paroxysmal cyanosis during crying + harsh systolic murmur → Think RVOT obstruction from Tet spells in TOF)
- Note: Crying/feeding → ↑ RVOT obstruction → ↓ pulmonary blood flow → Tet spells
- Squatting improves symptoms → ↑ SVR → ↓ right-to-left shunting → ↑ pulmonary blood flow
22. A 4-year-old boy presents with dyspnea and hepatomegaly. One month ago, he had fever, conjunctivitis, rash, and cracked lips. What is the cause?
➔ Congestive heart failure due to prior Kawasaki disease (coronary aneurysm or myocarditis)
- Note: Diagnosis = ≥5 days fever + ≥4 of: bilateral conjunctivitis, oral changes, polymorphous rash, cervical LAD, extremity changes
- Treatment = IVIG + aspirin
- The only condition in which you can give aspirin to a child (due to risk of Reye syndrome)
- Differentiate from Hand-Foot-Mouth Disease → Presents with oral ulcers + vesicular rash on palms, soles, and buttocks → No conjunctivitis or prolonged fever, and no cardiac sequelae
23. A 15-year-old boy collapses during basketball practice.A harsh systolic murmur is heard best at the left lower sternal border and increases with Valsalva. What is the diagnosis?
➔ Hypertrophic cardiomyopathy (Exertional syncope + systolic murmur that ↑ with Valsalva → Think HCM)
- Note: Murmur ↑ with ↓ preload (e.g., Valsalva, standing).
- Screening with → ECG + Echocardiogram.
- Management → Beta blockers, CCBs, activity restriction; ICD if prior syncope or arrhythmia
- In older adults (>70), exertional syncope with systolic murmur → Think aortic stenosis (murmur ↑ with squatting, ↓ with Valsalva)
24. A 6-year-old boy presents with headaches and fatigue. BP is 140/90 in the arms and 90/60 in the legs. On exam, femoral pulses are weak and delayed. What is the next step to confirm the diagnosis?
➔ Echocardiogram (Upper extremity HTN + diminished femoral pulses + headache + epistaxis → Think Coarctation of the Aorta)
- Note: May present in infancy with heart failure or in childhood with HTN + claudication
- CXR shows → Rib notching, “3 sign”
Respiratory Disorders
25. A 2-year-old girl has recurrent episodes of crying followed by breath-holding, cyanosis, stiffness, and brief loss of consciousness. What is the next step in management?
➔ Reassurance + screen for iron deficiency anemia (Typical breath-holding spells → benign but often linked to iron deficiency)
- Note: Classic triggers: Emotional distress or minor injury → crying → apnea → LOC
- Self-limited: Resolves by age 4–6 years
26. A 2-year-old boy is brought to the ED with a 1-day history of low-grade fever, hoarseness, and a barking cough. He has inspiratory stridor and subcostal retractions. What is the next step in management?
➔ Administer corticosteroids ± nebulized epinephrine (Inspiratory stridor + barking cough + subglottic narrowing → Think Croup → treat with steroids ± racemic epi)
- Note: Key sign → steeple sign on x-ray (Narrowing of the subglottic trachea)
- Management:
○ Mild → cool mist + corticosteroids (e.g., dexamethasone)
○ Moderate–severe (stridor at rest, retractions) → add nebulized epinephrine
○ Impending respiratory failure (cyanosis, lethargy) → intubation.
27. A 4-year-old boy is brought to the ED with sudden-onset high fever, sore throat, and difficulty swallowing. He is drooling, sitting in a tripod position, and has a muffled voice. What is the next step in management?
➔ Prepare for endotracheal intubation in the OR (Acute upper airway obstruction + drooling + tripod + rapid onset → Think Epiglottitis → secure airway first)
- Note: If imaging is safe → Lateral neck X-ray shows → “Thumb sign” (enlarged epiglottis)
- Secure airway → Intubation in OR with anesthesia team ready
- Do not examine throat with tongue depressor → risk of sudden obstruction
28. A 2-month-old infant has noisy breathing that is worse when supine and improves when prone. Parents report inspiratory stridor that becomes louder during feeding, crying, or when agitated. What is the diagnosis?
➔ Laryngomalacia (Inspiratory stridor in infancy + worse supine + improves prone → Think laryngomalacia)
- Note: Onset usually at 4–8 weeks, resolves by 18–24 months
- Worsens with feeding, crying, supine position
Dr Chaigasame, LaryngomalaciaDrawing, CC BY 4.0
29. 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.
30. 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 Medium-dose ICS |
| Severe Persistent | Continuous symptoms, frequent nighttime | High-dose ICS + LABA ± Oral steroids |
31. 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
32. 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 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 entry, no improvement with albuterol |
| Asthma | Bilateral wheeze, chronic pattern, improves with bronchodilators |
| Bronchiolitis | Infant with URI + wheezing, viral prodrome, bilateral findings |
33. 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)
- Note: Causes of pneumonia:
○ Infants/young children → Staphylococcus aureus
○ Older children/adolescents → Pseudomonas aeruginosa
34. A 3-year-old boy is brought to the clinic due to hearing difficulties and occasional ear tugging. He recently recovered from a viral upper respiratory infection. Otoscopic exam reveals a dull, immobile tympanic membrane without erythema or bulging. What is the next step?
➔ Observation and follow-up (Hearing loss but no fever, no signs of acute infection → Think Otitis media with effusion → no antibiotics needed)
- Note: Eustachian tube obstruction or dysfunction leads to → the accumulation of serous fluid within the middle ear → leads to Otitis media with effusion
35. A 2-year-old boy presents with fever, irritability, and tugging at his right ear. He had a cold 3 days ago. Otoscopic exam shows a bulging, erythematous tympanic membrane with decreased mobility. What is the next step?
➔ Oral amoxicillin (Fever + bulging erythematous TM + recent URI → Think acute otitis media → treat with amoxicillin)
- Note: Most common pathogens: Strep pneumo, H. flu, Moraxella
- Complications if untreated → mastoiditis, tympanic membrane perforation, hearing loss, speech delay, meningitis, and brain abscess.
36. A 5-year-old child presents with poor school performance, daytime sleepiness, and loud snoring. The exam shows enlarged tonsils and adenoids. What is the diagnosis?
➔ Obstructive sleep apnea (OSA) (Loud snoring + daytime fatigue → sleep-disordered breathing → tonsillar/adenoidal hypertrophy on exam → classic pediatric OSA presentation)
- Note: Polysomnography → is the gold standard for diagnosis
- Airway obstruction can lead to → pulmonary hypertension → leading to cor pulmonale
37. A 9-year-old boy with sickle cell disease presents with fever, cough, and shortness of breath. CXR shows a new left lower lobe infiltrate. What is the diagnosis?
➔ Acute chest syndrome (New infiltrate + fever + respiratory symptoms in sickle cell disease → Think ACS)
- Note: Common trigger → Bacterial/viral infection
- Management:
○ Immediate empiric antibiotics after cultures
○ Oxygen support, pain control - Differentiate from Pulmonary embolism → Less common in children; no fever or infiltrate, risk ↑ in adults or central lines.
Neurology & Neuromuscular Disorders
38. A newborn has microcephaly, smooth philtrum, thin vermilion border, and small palpebral fissures. The mother drank alcohol throughout pregnancy. What is the diagnosis?
➔ Fetal alcohol syndrome (Facial dysmorphisms + growth delay + maternal alcohol use → Think FAS)
- Note: It is the most common preventable cause of intellectual disability.
Fetal alcohol syndrome
- Differentiate from Down syndrome:
○ FAS → smooth philtrum, thin vermilion border, maternal alcohol use
○ Down syndrome → upslanting palpebral fissures, single palmar crease, epicanthal folds
39. A 2-month-old infant presents with poor feeding, weak cry, and progressive hypotonia. On exam, the infant is areflexic, with tongue fasciculations and a “floppy baby” appearance. What is the diagnosis?
➔ Spinal muscular atrophy type I (Werdnig-Hoffmann disease) (Floppy baby + tongue fasciculations + areflexia + feeding/respiratory difficulty → Suggests SMA type I)
- Note: Respiratory failure is the most common cause of death within the first year
- Differentiate from Infantile botulism → Also causes hypotonia and poor feeding, but with pupillary involvement and constipation
40. A newborn has hypotonia, poor feeding, and a weak cry. His mother has difficulty releasing her grip. On exam, the infant has facial weakness and absent reflexes. What is the next step to confirm the diagnosis?
➔ Genetic testing for CTG repeat expansion (Hypotonia + difficulty releasing her grip → Think congenital myotonic dystrophy)
- Note: Other classic findings include → testicular atrophy, frontal baldness, cataracts
41. A 4-year-old boy presents with frequent falls, difficulty rising from a sitting position, calf pseudohypertrophy, and a positive Gower sign. What is the next best step to confirm the diagnosis?
➔ Genetic testing (proximal weakness + calf pseudohypertrophy + Gower sign → Think Duchenne muscular dystrophy→ confirm with genetic testing)
- Note: Genetic testing → detects absent dystrophin
- Differentiate from Becker → later onset (adolescence) + reduced dystrophin
42. A 6-year-old girl is brought by her teacher due to frequent brief episodes of staring lasting about 10 seconds. She is unresponsive during these episodes but returns to baseline immediately afterward with no confusion. EEG shows 3-Hz spike-and-wave discharges. What is the treatment?
➔ Ethosuximide (Sudden brief staring spells + no postictal confusion + 3-Hz spike-and-wave on EEG → Indicates absence seizure → Treat with Ethosuximide)
- Note: Often remits in adolescence
43. A 2-year-old girl has a generalized tonic-clonic seizure lasting 2 minutes during a febrile illness. She quickly returns to baseline. There is no focality or prior seizure history. What is the next step in management?
➔ Reassurance and antipyretics (Generalized seizure <15 min + no recurrence or focality + age 6 months–5 years → Simple febrile seizure)
- Note: Treat fever for comfort; no antiepileptics indicated
- Complex if >15 min, focal, or recurrent — may need further evaluation
44. A 10-month-old boy is not sitting without support or bearing weight on his legs. He was born at 29 weeks. Exam shows hypertonia, scissoring of the legs, and persistent primitive reflexes. What is the diagnosis?
➔ Cerebral palsy (Prematurity + motor delay + hypertonia + persistent primitive reflexes → Think CP)
- Note: Most common cause = prematurity → leading to periventricular leukomalacia
- Persistent Moro or tonic neck reflex → classic clue
45. A newborn has a soft, non-fluctuant swelling over the parietal bone that does not cross suture lines. The swelling appeared hours after birth and has not increased in size. What is the most likely diagnosis?
➔ Cephalohematoma (Subperiosteal bleed limited by sutures → Suggests cephalohematoma)
- Note: Subperiosteal hemorrhage → confined to one cranial bone
- Appears after birth and resolves spontaneously over weeks
- Differentials:
○ Caput succedaneum: crosses sutures, present at birth
○ Subgaleal hemorrhage: life-threatening, fluctuant and crosses sutures, risk of hypovolemic shock
46. A newborn has a midline lumbosacral mass covered by a tuft of hair. Neurological exam is normal. What is the next step?
➔ Spinal ultrasound (Lumbosacral skin findings without neuro deficits → Evaluate for spinal dysraphism)
- Note: Skin markers → sacral dimple, hair tuft, hemangioma → prompt imaging
- Ultrasound if <6 months, MRI if older or if ultrasound is inconclusive
47. A premature infant (28 weeks gestation) develops lethargy, bulging fontanelle, and hypotonia on day 3 of life. What is the diagnosis?
➔ Intraventricular hemorrhage (Classic complication of prematurity → Germinal matrix hemorrhage)
- Note: Risk ↑ in <32 weeks or <1500 g birth weight
- Diagnosed by → Cranial ultrasound
48. A 10-year-old boy with a history of sickle cell disease presents with sudden right arm weakness and facial droop. CT head shows no hemorrhage. What is the most likely cause of his symptoms?
➔ Ischemic stroke due to vaso-occlusion (Sickle cell + acute focal deficits → Think ischemic stroke from cerebral vaso-occlusion)
- Note: Sickle cell disease is the most common cause of pediatric ischemic stroke
- Manage with → Exchange transfusion to rapidly ↓ HbS
- Hemorrhagic stroke in children → usually from trauma or AV malformation rupture
Development, Behavior, & Puberty Disorders
49. A 6-month-old infant rolls over and has started to sit with support. What language milestones should be present at this age?
➔ Babbling
- Note: Infant Developmental Milestones (0–12 months)
| Domain | Milestones by Age |
|---|---|
| Motor | Rolls over (~4 months), Sits with support (~6 months), Stands (~10 months) |
| Social | Social smile (~2 months), Stranger anxiety (~9 months) |
| Language | Babbling (~6 months), Says “Mama”/“Dada” (~10 months) |
50. A 2-year-old boy walks, climbs stairs, and kicks a ball. What is normal social behavior at this age?
➔ Parallel play
- Note: Toddler Developmental Milestones (12–36 months)
| Domain | Milestones by Age |
|---|---|
| Motor | Walks (12 months), Climbs stairs (18 months), Kicks ball (24 months) |
| Social | Rapprochement (24 months), Parallel play (24–36 months) |
| Language | Uses 200 words (2 years), 300+ words (3 years) |
51. A 4-year-old girl rides a tricycle and plays with other kids in a group. What language milestone is appropriate for her age?
➔ Tells simple stories
- Note: Toddler Developmental Milestones (12–36 months)
| Domain | Milestones by Age |
|---|---|
| Motor | Tricycle (3 yr), Hops (4 yr), Ties shoes (5 yr) |
| Social | Cooperative play (4 yr) |
| Language | Understands 1000 words (3 yr), Can tell detailed stories (4 yr) |
52. A 12-year-old boy is evaluated for short stature. His height has consistently tracked below the 5th percentile. His parents are of average height. Bone age is delayed compared to chronological age. What is the diagnosis?
➔ Constitutional growth delay (Short stature + delayed bone age + normal parents → Think constitutional growth delay)
- Note: Normal variant of growth → eventual normal adult height
- Differentiate from familial short stature → bone age = chronological age, short parents, height tracks consistently low
53. A 6-year-old boy is brought to the ED with a spiral humeral fracture. His caregiver says he fell off the bed, but the injury seems inconsistent with the reported low-impact fall. What is the next step in management?
➔ Report suspected child abuse to Child Protective Services (Multiple injuries at different stage + inconsistent injuries with developmental stage or provided history → suspect child abuse)
- Note: 1st step in management is → Immediate safety first: Hospitalize if needed
○ Mandatory reporting to CPS – you do not need proof, only reasonable suspicion - Osteogenesis imperfecta can mimic abuse but has positive family history, blue sclera, opalescent teeth, and is an autosomal dominant collagen type I defect.
54. A 2-year-old girl is brought in by her parents due to concerns about occasionally touching her genitals, refusing to share toys, and being anxious during physician visits. What is the next step?
➔ Reassure the parents (Normal sexual behavior in toddlers begins around age 2 with solitary genital touching)
- Note: Other normal behaviours include → Refusal to share toys, nighttime awakenings, picky eating, and anxiety
55. A 3-year-old girl is brought to the clinic for evaluation after her daycare teacher reports that she was seen trying to simulate oral-genital contact with another child. She also uses sexual language. What is the next step?
➔ Report to child protective services (suspected sexual abuse)
- Note: Red flags for sexual abuse:
○ Sexualized behavior involving others
○ Imitating sexual acts (eg, intercourse, oral-genital contact)
○ Excessive preoccupation or aggression related to sexuality
56. A 10-year-old boy with persistent inattention and hyperactivity across home and school settings is diagnosed with ADHD. His parents ask about the most effective treatment option. What is the best initial management?
➔ Stimulant medication (eg, methylphenidate) (First-line for ADHD with functional impairment → think Stimulants +/- Behavioral therapy)
- Note: If stimulants are contraindicated (history of substance use) or parent refusal → use Non-stimulants: Atomoxetine (NE reuptake inhibitor), Guanfacine, clonidine (α2 agonists)
- Treatment is only behavioral if <6 years (No drugs)
- Always assess impairment in ≥2 settings (parents and teachers fill out behavioral rating scales).
57. An 8-year-old boy often argues with teachers, deliberately refuses to follow instructions, and is spiteful toward authority figures. What is the diagnosis?
➔ Oppositional Defiant Disorder (Angry/irritable mood + argumentative/defiant behavior toward authority → Think Oppositional Defiant Disorder)
- Note: Treat with cognitive behavioral therapy + parent management training.
- Unlike Conduct Disorder, Oppositional Defiant Disorder does not involve aggression toward people or animals, destruction of property, or serious violation of rules.
58. A 10-year-old boy presents with frequent throat clearing, facial grimacing, and sudden shoulder jerks for the past year. He also blurts out words uncontrollably. What is the diagnosis?
➔ Tourette Syndrome (Multiple motor + ≥1 vocal tic for >1 year → Think Tourette)
- Note: Treatment:
○ First-line: Behavioral therapy (habit reversal training)
○ If severe: Medications like tetrabenazine, antipsychotics (e.g., risperidone) - Don’t confuse it with transient tic disorder (<1 year) or chronic motor/vocal tic disorder (only one type of tic).
59. A 7-year-old girl refuses to go to school, saying she fears something bad will happen to her parents. She complains of stomachaches but has a normal physical exam. What is the diagnosis?
➔ Separation anxiety disorder (Excessive worry about separation + somatic complaints → Think separation anxiety)
- Note: Common in children 6–12 years
- Differentiate from normal development by intensity and functional impairment
60. A 3-year-old boy is brought in for evaluation due to delayed speech and minimal interest in other children. He avoids eye contact, lines up toys repetitively, and becomes distressed with small routine changes. What is the next step in management?
➔ Intensive behavioral intervention (Delayed communication + impaired social interaction + restricted/repetitive behaviors → think Autism Spectrum Disorder)
- Note: It can be diagnosed even in 2-year-old kids.
- Preference for certain food types or shapes alone is not ASD — it must be accompanied by developmental or social delays to meet diagnostic criteria.
Differentiate from:
| Disorder | Key Features |
|---|---|
| Language disorder | Isolated language delay, normal social interaction. |
| Intellectual disability | Global delays, social reciprocity may be preserved |
61. A 6-year-old boy has global developmental delays in motor and language skills. He is affectionate and socially engaged. What is the most likely diagnosis?
➔ Intellectual disability (Global delays + preserved social reciprocity → Think Intellectual disability)
- Note: Workup → cognitive testing, hearing/vision screening
62. A 7-year-old boy continues to wet the bed at night despite toilet training. Urinalysis is normal. What is the next best step in management?
➔ Begin motivational therapy (eg, reward system, voiding before bed) (Involuntary urination ≥ age 5 + normal urinalysis → Think Primary Nocturnal Enuresis)
- Note: Most commonly due to delay in maturation
- Initial Workup:
○ Urinalysis → to rule out secondary causes (e.g., UTI, diabetes mellitus, diabetes insipidus).
○ Evaluate psychosocial stressors - If persistent/severe despite motivational therapy → Use Enuresis alarm + Desmopressin
63. A 15-year-old girl becomes distant from her parents and forms a strong attachment to her boyfriend. She sleeps late and has difficulty waking to school. What is the next step in management?
➔ Reassure and educate about sleep hygiene (Identity formation + circadian delay →Think normal Adolescent Development)
- Note: Normal Adolescent behaviors include:
○ Questioning authority, parental conflict
○ Romantic infatuation, emotional intensity
○ Dieting and a degree of concern about body weight (but normal BMI)
○ Sleep Changes → Later sleep onset, trouble waking early - Distinguish from psychiatric disorders by preserved function and appropriate social context
64. A 7-year-old girl presents to you with complaints of increased hair in her axillae and facial acne. His parents also report that she has had some breast development throughout the past 6 months. What is the diagnosis?
➔ Precocious puberty (Puberty signs in <8 year old girls or <9 year old boys)
- Note: For precocious puberty → Next best step is to assess the bone age
- If bone age is:
○ Increased → Next best step is to assess the basal LH levels
○ Decreased → Diagnose it as isolated pubarche or isolated thelarche - If basal LH levels:
○ Increased → Confirms central precocious puberty
○ Decreased → Do GnRH stimulation test → If LH levels are still low → Confirms peripheral precocious puberty
65. A 6-year-old girl presents to you with complaints of onset of menstruation and acne. On bone analysis, you find the bone age to be advanced and underlying LH levels to be low. What is the diagnosis?
➔ Peripheral precocious puberty
- Note: Likely source for precocious puberty is → Peripheral tumor or congenital adrenal hyperplasia
- Estrogen-producing tumor → Granulosa cell tumor → Call-Exner bodies observed histologically
- Pituitary GnRH producing tumor → Can lead to central precocious puberty → Treat with leuprolide
66. A 13-year-old girl has been brought to you by her mother for right breast tenderness for the past two months. The right breast is slightly tender and raised, while the left breast is unremarkable. What is the next step in management?
➔ Reassurance (This is normal puberty, for which we would just simply reassure)
- Note: Similarly, for mild vaginal spotting in young adolescent girls, → Likely also indicates the start of menstruation and puberty → The best next step is to reassure
- Boys can also develop unilateral or bilateral breast mass or tenderness during puberty → The best next step is to reassure
- Imaging is needed when:
○ Rapid progression
○ Associated mass, skin changes, or prominent discharge
○ Symptoms outside the pubertal age
67. A 14-year-old girl presents with primary amenorrhea and monthly lower abdominal pain. The physical exam shows a bulging bluish vaginal mass. What is the next step in management?
➔ Pelvic ultrasound (Amenorrhea + cyclic pain + bulging mass → Think hematocolpos from Imperforate hymen)
- Note: Treat with → Transvaginal resection and drainage
68. A 17-year-old girl presents with irregular, heavy menstrual bleeding. Her day-21 serum progesterone level is low. What is the most likely underlying cause of her abnormal bleeding?
➔ Anovulatory cycle (Unopposed estrogen → endometrial proliferation without secretory transformation → heavy, irregular bleeding)
- Note: Common in adolescents due to immature hypothalamic-pituitary-ovarian (HPO) axis
- Occurs also in perimenopause, PCOS, obesity, or thyroid disorders
69. A 15-year-old girl with known Turner syndrome presents for routine follow-up. She has short stature and primary amenorrhea. What is the most likely long-term complication in this patient?
➔ Osteoporosis (Estrogen deficiency + Turner syndrome → ↑ risk of decreased bone mineral density)
- Note: Caused by primary ovarian failure and low estrogen levels
- Requires estrogen replacement + bone density monitoring
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GI, Nutrition, & Metabolism
70. A 2-year-old boy is found to have a soft, reducible umbilical hernia measuring 1.3 cm. He is otherwise healthy with normal development. What is the next step in management??
➔ Observation (most resolve spontaneously by age 3–5) (Soft + reducible + age < 5 years + <1.5 cm → Suggests likely spontaneous closure)
- Note: Most umbilical hernias close spontaneously by age 3–5 years
- Surgical repair is indicated if:
○ Hernia persists > age 5
○ Incarceration or strangulation
○ Defect is ≥1.5 cm in diameter (less likely to close spontaneously) - Surgery is recommended after age 4 years due to high risk for recurrence if surgery is completed at a younger age.
71. A 3-month-old infant is brought in for frequent spit-ups after feeding. He is otherwise healthy, feeding well, gaining weight, and not irritable. What is the next step in management?
➔ Reassurance and conservative measures (Healthy infant + adequate weight gain → Physiologic GERD)
- Note: If Alarming features (e.g., weight loss, irritability, feeding refusal) → Evaluate further ± PPI trial
72. A 2-year-old boy presents with fever, vomiting, and watery diarrhea for one day. He is alert but has dry lips and mildly delayed capillary refill. Vitals are normal. What is the next step in management?
➔ Oral rehydration therapy (ORT) (Mild dehydration from gastroenteritis → start with oral fluids)
- Note: Signs of mild volume depletion → Dry mucosa, mildly delayed capillary refill, normal BP
- ORT is preferred for mild to moderate dehydration
73. A 9-month-old infant presents with lethargy and decreased urine output after 2 days of profuse watery diarrhea. On exam, he has dry mucous membranes, a sunken anterior fontanelle, delayed capillary refill, and cool extremities. What is the most appropriate next step in management?
➔ Administer isotonic IV fluids (Signs of moderate to severe dehydration → Think initial fluid resuscitation)
- Note: Signs of moderate/severe dehydration → Tachycardia, lethargy,altered mental status, poor perfusion (delayed cap refill), sunken fontanelle, oliguria
74. A 9-month-old infant presents with profuse diarrhea, lethargy, dry mucous membranes, and delayed capillary refill. Labs reveal low bicarbonate, low pH, and elevated anion gap. What is the primary cause of the acid-base disturbance?
➔ Lactic acid accumulation (Hypoperfusion from dehydration → tissue hypoxia → ↑ lactic acid → metabolic acidosis)
- Note: Hypovolemia from diarrhea → ↓ perfusion → anaerobic metabolism
- Treat with → Fluid resuscitation → restores perfusion & clears lactate
75. A 4-day-old newborn presents with jaundice. Total bilirubin is 10 mg/dL, with indirect predominance. The infant is feeding well, has normal stool and urine, and was born full term. What is the cause of his jaundice?
➔ Physiologic jaundice (Onset after 24 hours + indirect hyperbilirubinemia + well-appearing → Think physiologic jaundice)
- Note: Pathologic if: Onset <24h, direct bilirubin ↑, rising >5/day
- Phototherapy if → total bilirubin >15 mg/dL in term infant
- Exchange transfusion if → total bilirubin >25 mg/dL or signs of acute bilirubin encephalopathy
76. A 4-week-old boy presents with nonbilious projectile vomiting and weight loss. Physical exam reveals a small, firm, ovoid mass in the epigastric region. What is the next step to confirm the diagnosis?
➔ Abdominal ultrasound (Projectile nonbilious vomiting + palpable mass + metabolic alkalosis + around one month of age→ Suggests pyloric stenosis)
- Note: Electrolyte disturbances → Hypochloremic, hypokalemic metabolic alkalosis due to vomiting
- Abdominal U/S → Shows thickened, elongated pylorus
- Treatment: IV fluids+ electrolytes correction+ pyloromyotomy after correction of electrolytes
77. A newborn develops bilious vomiting shortly after birth and has not passed meconium. Abdominal X-ray reveals a “double bubble” sign with no distal gas. What is the most likely diagnosis?
➔ Duodenal atresia (Newborn + early vomiting + double bubble on X-ray → Classic for duodenal atresia)
- Note: Strong association with Down syndrome
- Management → NG tube decompression + IV fluids → followed by surgical duodenoduodenostomy
78. A 6-week-old infant presents with persistent jaundice, pale stools, and dark urine. Labs show elevated direct bilirubin. What is the next step in management?
➔ Abdominal ultrasound (Conjugated hyperbilirubinemia + acholic stools + from 2 to 8 years → Think biliary atresia; US screens for absent/abnormal gallbladder)
- Note: Diagnosis → US → HIDA scan → Confirm with intraoperative cholangiogram
- Treatment → Kasai procedure (hepatoportoenterostomy) ± eventual liver transplant
79. A newborn with bilious vomiting, sudden abdominal pain, bloody diarrhea, Fever and leukocytosis. x-ray showing intestinal dilation What’s the next best step in diagnosis?
➔ Upper GI barium series (Bilious vomiting in a neonate is a red flag for midgut volvulus, especially with signs of bowel ischemia like bloody stools and fever)
- Note: Malrotation is the predisposing factor.
- Treatment is an emergency Ladd procedure after resuscitation.
- Differentiate from Sigmoid volvulus → adolescents/adults, abdominal distension, constipation, diagnosed with abdominal x-ray showing “coffee bean sign”.
80. A 2-year-old boy presents with painless dark red stools and iron deficiency anemia. What is the best next diagnostic step?
➔ Meckel scan (Technetium-99m pertechnetate) (Painless hematochezia + anemia → suspect Meckel diverticulum → scan detects ectopic gastric mucosa in ileal outpouching)
- Note: Classic triad: Painless GI bleeding + anemia + age < 5 years.
81. A 9-month-old boy presents with episodes of severe, colicky abdominal pain followed by periods of normal activity. He had a stool mixed with blood and mucus. On exam, there is a palpable sausage-shaped mass in the right upper quadrant. What is the next step?
➔ Air or contrast enema (Recurrent colicky pain + “currant jelly” stool + RUQ mass → Think Intussusception → Treat with enema)
- Note: Pathologic lead point (e.g., Meckel’s, polyp, lymphoma) more common in older children
- Ultrasound shows → Target sign (transverse view)
- First-line for both diagnosis and reduction → Air or contrast enema
82. A 3-year-old child has large, painful bowel movements every 3–4 days. He avoids using the toilet, and his stools clog it frequently. What is the best initial treatment?
➔ Oral polyethylene glycol (Chronic constipation + stool withholding + large caliber stool → Think functional constipation → Treat with laxatives)
- Note: Red flags: Delayed meconium (>48h), poor growth, abnormal neuro exam, ribbon stools → Evaluate for Hirschsprung or spinal cord disorders
83. A newborn has not passed meconium by 48 hours of life and presents with abdominal distension. On the rectal exam, there is explosive expulsion of stool. What is the next step to confirm the diagnosis?
➔ Rectal suction biopsy (Delayed meconium + explosive stool on exam → Suggests Hirschsprung disease → biopsy confirms aganglionosis)
- Note: Can also present in children → as chronic constipation
- Anorectal manometry may be done first → reveals lack of internal anal sphincter relaxation (used as a screening test)
- Treat with → Surgical resection of aganglionic segment + reanastomosis of normal bowel
84. A premature newborn at 32 weeks gestation develops abdominal distension, feeding intolerance, and bloody stools on day 5 of life. X-ray reveals pneumatosis intestinalis. What is the next best step in management?
➔ Bowel rest (NPO), nasogastric decompression, IV fluids, and broad-spectrum antibiotics (Prematurity + abdominal distension + bloody stools + pneumatosis → Think Necrotizing Enterocolitis)
- Note: Risk factors: Prematurity, enteral feeding
- Pneumatosis intestinalis = gas in bowel wall
85. A 1-year-old child with poor dietary intake and limited sun exposure presents with leg bowing and delayed walking. What laboratory findings are present?
➔ ↓ Calcium, ↓ Phosphate, ↑ Alkaline phosphatase, ↑ PTH (Classic lab pattern in vitamin D deficiency leading to→ rickets)
- Note: Signs of rickets: Bowed legs, frontal bossing, craniotabes, rachitic rosary
86. A 15-month-old boy presents with low weight for age but normal height and head circumference. He drinks 3–4 cups of juice daily and eats small amounts of table food. What is the next step in management?
➔ Dietary history and calorie count diary (Low weight with normal height & head size → Think poor caloric intake, assess dietary habits first)
- Note: Weight ↓ with normal length & head circumference → suggests inadequate intake
87. A 6-year-old boy presents with nocturnal perianal itching. His symptoms have persisted for a week and worsen at night. What is the most appropriate next step in management?
➔ Treat with albendazole (Nocturnal pruritus + typical age → Suggests Enterobius vermicularis (pinworm))
- Note: Differentiate from perianal dermatitis (Strep/yeast) → Red, painful rash ± discharge, not itchy only at night
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Nephrology & Urology
88. A 5-year-old boy presents with periorbital swelling and foamy urine. He had a mild upper respiratory infection a week ago. The physical exam shows pitting edema in the lower extremities. What is the diagnosis?
➔ Minimal change disease (Most common nephrotic syndrome in children; often follows infection)
- Note: Complications include:
○ Hypercoagulability (loss of antithrombin III)
○ Infection risk (loss of IgG)
○ Hyperlipidemia (↑ hepatic lipoprotein synthesis due to ↓ oncotic pressure)
89. A 6-year-old boy presents with periorbital swelling, dark cola-colored urine, and elevated blood pressure 2 weeks after recovering from a sore throat. Urinalysis reveals hematuria and mild proteinuria. What is the next step to confirm the diagnosis?
➔ Measurement of serum C3 (Periorbital edema + hematuria + hypertension after recent streptococcal infection → Think poststreptococcal glomerulonephritis)
- Note: low C3 confirms poststreptococcal glomerulonephritis
90. A 2-month-old boy presents with fever and poor feeding. Urinalysis confirms a UTI. What should be the next best step in evaluation?
➔ Renal and bladder ultrasound (UTI in child <2 years → Screen for congenital urinary tract abnormalities)
- Note: Febrile UTI in children <2 years→ Often linked to structural abnormalities.
- Initial test: Renal & bladder ultrasound (non-invasive).
- Further testing: Voiding cystourethrogram (VCUG) if ultrasound is abnormal or recurrent UTI.
91. A 3-year-old boy presents with his second febrile urinary tract infection in 4 months. What is the most likely underlying diagnosis?
➔ Vesicoureteral reflux (VUR) (Recurrent febrile UTIs + age <5 → Think VUR)
- Note: Confirm with → voiding cystourethrography (VCUG) after ≥2 febrile UTIs.
- Management:
○ Antibiotic prophylaxis if recurrent UTIs
○ Surgical correction if refractory to meds
92. A 10-year-old boy is found to have proteinuria on a random urine dipstick during a routine school physical. He has no edema, normal blood pressure, and normal renal function. What is the next step in management?
➔ Repeat urine dipstick on two separate occasions (Isolated proteinuria in a well child → Think transient proteinuria)
- Note: Transient proteinuria → Most common cause in children; often triggered by fever, stress, or exercise
- Differentiate from Glomerular disease → Would show hematuria, hypertension, or elevated creatinine
93. A 10-year-old child presents with new-onset hypertension. On examination, there is an abdominal bruit. What is the cause?
➔ Renal artery stenosis (Abdominal bruit + pediatric hypertension → Think renovascular cause like RAS)
- Note: Secondary HTN in kids → Most commonly due to renal/renovascular disease.
- Treatment:
○ First-line → ACEI, ARBS.
○ Refractory cases → Angioplasty (especially if medication fails).
94. A 15-year-old boy presents with sudden, severe left testicular pain and swelling. On exam, the left testicle is elevated, tender, and lies transversely. The cremasteric reflex is absent. What is the next step in management?
➔ Immediate surgical exploration of the scrotum (Teenage boy + sudden testicular pain + absent cremasteric reflex → Think testicular torsion → Go straight to surgery)
- Note: Do NOT delay for imaging if diagnosis is clear
- Doppler US only if diagnosis is uncertain → ↓/absent blood flow
Differentiation Table
| Condition | Clue | How to Differentiate |
|---|---|---|
| Testicular torsion | Sudden pain, absent cremasteric reflex | Surgical emergency, no relief on elevation |
| Epididymitis | Gradual pain, fever, pyuria | Pain relieved with scrotal elevation, normal cremasteric reflex |
| Torsion of appendix testis | Localized tenderness, not whole testicle | – |
95. A 2-month-old boy is brought in for a painless scrotal swelling noticed during bathing. The swelling is soft, transilluminates with light, and is not tender. What is the next step?
➔ Observation (Painless, transilluminating scrotal swelling in an infant → Suggests communicating hydrocele → observe if <1 year)
- Note: Resolves spontaneously in most infants by 12 months
- Surgery (hydrocelectomy) if persists after 1 year or if enlarging
96. A 3-day-old boy presents with poor urine output and respiratory distress. Prenatal ultrasound showed bilateral hydronephrosis and a distended bladder. Postnatal imaging shows a dilated posterior urethra and thick-walled bladder. What is the diagnosis?
➔ Posterior urethral valves (Newborn boy + bilateral hydronephrosis + poor urine output → Think PUV
- Note: Diagnosed by → Voiding cystourethrogram (VCUG)
- Initial management → Bladder catheterization, followed by endoscopic ablation
Endocrinology
97. A 17-year-old boy is evaluated for delayed puberty and gynecomastia. He is tall with small, firm testes and long legs. Labs show low testosterone and elevated FSH and LH. What is the next step in management?
➔ Karyotype analysis (Hypergonadotropic hypogonadism + gynecomastia + small testes → Suspect Klinefelter → Confirm with karyotype)
- Note: Differential Diagnosis:
○ Constitutional delay of puberty → Normal testes size + normal labs + delayed bone age
○ Androgen insensitivity syndrome → 46,XY genotype + female phenotype + no pubic/axillary hair
98. A newborn is found to have hypotonia, umbilical hernia, and prolonged jaundice. What is the next step in diagnosis?
➔ Measurement of TSH and T4 (Hypotonia + umbilical hernia + prolonged jaundice → think congenital hypothyroidism → Confirm with thyroid function tests)
- Note: Other classic features: macroglossia, hoarse cry, cold extremities
- Screen with TSH (↑) and T4 (↓) → confirm diagnosis
- Early levothyroxine prevents permanent intellectual disability
99. A 12-year-old girl presents with abdominal pain, vomiting, and rapid deep breathing. The exam shows dry mucous membranes and a fruity breath odor. Labs reveal hyperglycemia. What is the next step in treatment?
➔ Isotonic fluid resuscitation (Polyuria, vomiting, abdominal pain, Kussmaul breathing, fruity breath → Think DKA → Stabilize with fluids first before insulin)
- Note: Treat with → IV normal saline + electrolyte correction + insulin
- Monitor closely → total body K⁺ as it is low even if serum is normal or high → replace as needed before insulin.
100. A 5-day-old girl presents with vomiting, lethargy, hypotension, and ambiguous genitalia. Labs reveal hyponatremia, hyperkalemia, and hypoglycemia. What is the next best step in management?
➔ Administer hydrocortisone, fludrocortisone, and IV fluids (Ambiguous genitalia + salt-wasting crisis → Think Congenital Adrenal Hyperplasia → Treat with steroids + fluid resuscitation)
- Note: Most common cause: 21-hydroxylase deficiency
- Confirm with ↑ 17-hydroxyprogesterone
Hematology & Oncology
101. A 5-year-old boy presents with fever, petechiae, lymphadenopathy, and hepatosplenomegaly. CBC reveals pancytopenia. What is the next best step to confirm the diagnosis?
➔ Bone marrow biopsy (Pancytopenia + lymphadenopathy + hepatosplenomegaly → Suggests acute lymphoblastic leukemia)
- Note: ALL is the most common childhood malignancy
- Bone marrow biopsy: diagnostic when >20% lymphoblasts
102. A 4-year-old child presents with pallor, hematuria, and decreased urine output several days after an episode of bloody diarrhea. Labs show anemia, thrombocytopenia, and elevated creatinine. What is the management?
➔ Supportive care (IV fluids, monitoring, dialysis if needed) (Hemolytic anemia + thrombocytopenia + acute kidney injury → Think HUS → Managed conservatively)
- Note: Bloody diarrhea followed by → Bloody urine → Think HUS
- Avoid antibiotics & platelet transfusion → may worsen microthrombi
- Dialysis if severe renal failure or electrolyte derangements
103. A newborn male has persistent bleeding after circumcision and a large cephalohematoma. Labs show ↑ PTT with normal PT and platelet count. What is the diagnosis?
➔ Hemophilia A (Prolonged bleeding + ↑ PTT + normal PT/platelets → Think factor VIII deficiency affecting intrinsic pathway)
- Note: X-linked recessive so → seen in boys
- Classic neonatal signs → bleeding after procedures (e.g., circumcision) or cephalohematoma
- In older boys → hemarthrosis, deep muscle hematomas
104. A 2-day-old Mediterranean male newborn presents with jaundice and anemia. Labs show elevated unconjugated bilirubin and a negative Coombs test. What is the next step to confirm the diagnosis and guide management?
➔ Measurement of G6PD enzyme activity (Unconjugated hyperbilirubinemia + anemia + Coombs-negative + ethnicity → Suggests G6PD deficiency)
- Note: Confirmatory test: G6PD assay → may be falsely normal during acute hemolysis
- Peripheral smear shoes → Heinz bodies (denatured hemoglobin) + bite cells (due to splenic removal)
- Supportive care: Hydration, phototherapy if bilirubin is high
- Avoid oxidative stressors: Sulfa drugs, fava beans, certain antibiotics (e.g., nitrofurantoin).
105. A 2-year-old boy presents with leukocoria noted by his parents in photos. Exam shows an absent red reflex in the left eye. What is the next step in management?
➔ Urgent ophthalmology referral for MRI of brain/orbits (Leukocoria in a child → suspect retinoblastoma → rule out bilateral/multifocal disease)
- Note: Associated with RB1 gene mutation (autosomal dominant) → screen siblings if familial
- RB1 gene mutation increases → risk of osteosarcoma
106. A 13-year-old boy presents with 2 months of worsening left knee pain and swelling. X-ray shows a destructive bone lesion with periosteal elevation and sunburst pattern. What is the next step to confirm the diagnosis?
➔ Biopsy of the lesion (Pain + swelling + destructive lesion + periosteal reaction → Suggests osteosarcoma → Confirm with biopsy)
- Note: Common in → adolescents and long bones
- Metastasis: Commonly spreads to lungs → baseline chest CT is essential
Allergy, & Immunology
107. A 10-month-old boy has had multiple episodes of otitis media and pneumonia. He has no tonsils on examination. Laboratory results show absent CD19+ B cells and severely decreased serum immunoglobulins. What is the next step in management?
➔ Start monthly IVIG therapy (Recurrent bacterial infections + ↓ all Ig + ↓ B cells (CD19+) → Suggests X-linked agammaglobulinemia → Give Ig replacement)
- Note: Absent tonsils, lymph nodes, and B cells (CD19−)
- Treatment: IVIG + avoid live vaccines
- Differentiate from Common variable immunodeficiency (CVID) → Presents in adolescence/adulthood with normal B cell count VS XLA = infancy + absent B cells
108. A 7-year-old boy has a history of recurrent sinus infections and recently developed an anaphylactic reaction during a plasma transfusion. Laboratory studies reveal undetectable IgA levels with normal IgG and elevated IgM. What is the diagnosis?
➔ Selective IgA deficiency (Recurrent sinopulmonary infections + anaphylaxis to blood products + isolated low IgA → Suggests IgA deficiency)
- Note: Patients may be asymptomatic or have recurrent mucosal infections (respiratory, GI)
- If asymptomatic → do not require specific monitoring.
- Treatment of IgA deficiency is directed toward the treatment of symptomatic infections.
109. A 2-month-old infant is brought to the clinic due to poor feeding, recurrent thrush, and multiple episodes of otitis media and pneumonia since birth. Laboratory evaluation shows low CD4+ T-cell count, and undetectable immunoglobulin levels. What is the e next step?
➔ Urgent hematopoietic stem cell transplantation (Recurrent infections + failure to thrive + low T cells + panhypogammaglobulinemia → Suggests SCID → Needs stem cell transplant)
- Note: Differentiate from HIV infection (perinatal) → Also causes low CD4+ and infections, but maternal HIV status usually positive and Ig levels may be high early
110. A 3-month-old boy is brought to the clinic for evaluation of recurrent ear infections. On examination, he has eczematous lesions on his trunk, petechiae, and scattered ecchymoses. Laboratory studies reveal thrombocytopenia with small platelets. What is the diagnosis?
➔ Wiskott-Aldrich syndrome (Eczema + thrombocytopenia + recurrent infections → Suggests Wiskott-Aldrich syndrome)
- Note: Differentiate from Atopic dermatitis → Eczema present, but normal platelet count and no severe infections
111. A 2-week-old infant presents with seizures and a history of congenital heart disease. Exam reveals low-set ears, micrognathia, and cleft palate. Labs show hypocalcemia and lymphopenia. What is the diagnosis?
➔ DiGeorge syndrome (Thymic/parathyroid hypoplasia + cardiac defects + facial features → Think DiGeorge syndrome)
- Note: Cause: 22q11.2 microdeletion → defective development of 3rd & 4th pharyngeal pouches
- Classic triad:
○ Hypocalcemia (→ seizures) due to parathyroid hypoplasia
○ T-cell deficiency (→ recurrent infections) due to thymic hypoplasia
○ Congenital heart disease (e.g., truncus arteriosus, TOF)
112. A 3-year-old boy presents with recurrent skin and lung infections caused by Staphylococcus aureus and Serratia marcescens. He has a history of poor wound healing and granuloma formation. What is the next step to confirm the diagnosis?
➔ Dihydrorhodamine (DHR) flow cytometry test (Recurrent catalase-positive infections + granuloma formation → Think CGD → Confirm with neutrophil oxidative burst test)
- Note: Diagnose with → DHR flow cytometry (preferred) or Nitroblue Tetrazolium test
- Management: Prophylactic TMP-SMX + itraconazole ± IFN-γ
113. A 2-month-old boy presents with recurrent skin and umbilical infections. His umbilical cord fell off at 4 weeks of age. Physical exam shows no pus formation at infection sites despite marked inflammation. What is the next step to confirm the diagnosis?
➔ Flow cytometry to assess CD18 expression on neutrophils (Delayed cord separation + recurrent infections + neutrophilia + no pus → Suggests Leukocyte Adhesion Deficiency)
- Note: Labs: Neutrophilia → but defective chemotaxis/adhesion
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Neonatology
114. A 5-day-old exclusively breastfed newborn presents with oozing from the umbilical stump and bruising on the abdomen. He did not receive intramuscular vitamin K at birth. What is the next best step in management?
➔ Administer intramuscular vitamin K and fresh frozen plasma (FFP) (Neonatal bleeding + no vitamin K prophylaxis → Treat with vitamin K + FFP)
- Note: The presentation will mostly be on a baby born at home
- FFP → provides clotting factors for rapid reversal
115. A 2-day-old newborn presents with mild conjunctival injection and watery eye discharge. He received topical erythromycin prophylaxis shortly after delivery. Physical exam reveals no purulent discharge or eyelid swelling. What is the diagnosis?
➔ Chemical conjunctivitis (<3 days after birth + mild discharge + recent erythromycin prophylaxis → Suggests chemical irritation rather than infection)
- Note: Chemical conjunctivitis: Occurs within <3 days of life; associated with topical prophylaxis (e.g., silver nitrate, erythromycin)
- Self-limited and does not require treatment
- VS Gonococcal conjunctivitis → occurs 3–5 days, purulent discharge
- VS Chlamydial conjunctivitis → 5–14 days, purulent discharge
116. A 4-day-old newborn presents with bilateral eyelid swelling, conjunctival injection, and thick purulent eye discharge. He was born vaginally to a mother who received no prenatal care. What is the most appropriate next step in management?
➔ Administer intramuscular ceftriaxone (Purulent discharge + eyelid swelling at 3–5 days → Think gonococcal conjunctivitis)
- Note: Topical erythromycin at birth is preventive but not curative
117. A full-term newborn is delivered vaginally with poor respiratory effort and flaccid tone. The heart rate is 110/min. After drying and warming, the infant remains apneic despite tactile stimulation. What is the next step?
➔ Positive-pressure ventilation (eg, bag-mask ventilation) (Apnea despite tactile stimulation → initiate PPV)
- Note: Initial steps → Drying, warming, stimulation, airway positioning
- If apnea or HR <100/min, begin PPV
- HR is the key guide:
○ HR <100 → PPV
○ HR <60 after PPV → start chest compressions
118. A premature infant born at 30 weeks develops tachypnea, nasal flaring, and cyanosis shortly after birth. CXR shows bilateral ground-glass opacities. What is the diagnosis?
➔ Neonatal respiratory distress syndrome (NRDS) (↓ surfactant → ↑ alveolar surface tension → alveolar collapse)
- Note: CXR → shows diffuse reticulogranular (ground-glass) opacities
- Prevention/Treatment:
○ Antenatal steroids to mother if preterm delivery expected
○ Exogenous surfactant + oxygen support postnatally
119. A premature infant born at 28 weeks develops persistent oxygen requirements beyond 28 days of life. He had neonatal respiratory distress syndrome and was treated with mechanical ventilation and surfactant. What is the diagnosis?
➔ Bronchopulmonary dysplasia (History of RDS & ventilation + persistent oxygen need >28 days leads to → Bronchopulmonary dysplasia)
- Note: Diagnosis: O₂ dependence >28 days + radiographic lung changes
- Management is → Supportive (oxygen, diuretics, bronchodilators if needed)
120. A 5-month-old infant is exclusively breastfed and has been growing appropriately. The mother asks if any supplements are needed at this time. What is the next best step in management?
➔ Start iron supplementation (Exclusively breastfed + age >4 months → Risk of iron deficiency → Begin iron supplements)
- Note: Breast milk meets full nutrition needs until 6 months, but iron stores deplete by 4–6 months
- Exclusively breastfed infants should receive:
○ Vitamin D starting in the first days of life
○ Iron supplementation beginning at 4–6 months
121. A 2-month-old infant born at 30 weeks’ gestation is exclusively breastfed and has been gaining weight appropriately since discharge from the NICU. What is the next step in management?
➔ Start iron and vitamin D supplementation (Prematurity + exclusive breastfeeding → Risk of iron & vitamin D deficiency → Supplement both)
- Note: Preterm infants (<37 weeks) have lower iron stores at birth → Start iron supplementation by age 1 month
- Vitamin D is also needed if infant is exclusively breastfed
122. A 2-day-old full-term newborn has multiple 1–2 mm yellowish pustules on an erythematous base over the trunk. The baby is afebrile, feeding well, and otherwise healthy. What is the next best step in management?
➔ Reassurance and routine care (Pustules on erythematous base, mainly on trunk within first 2–3 days → Think Erythema toxicum neonatorum → resolves in a few days)
123. A newborn born to a mother with poorly controlled gestational diabetes has a birth weight >4 kg and develops jitteriness and lethargy shortly after birth. What is the cause of this newborn’s symptoms?
➔ Neonatal hypoglycemia (Macrosomia + maternal diabetes + jitteriness after delivery → Think excess fetal insulin leads to → hypoglycemia)
- Note: Maternal hyperglycemia causes→ fetal hyperglycemia → leading to fetal hyperinsulinemia
- After delivery, maternal glucose supply stops but insulin remains → hypoglycemia
Musculoskeletal & Ortho
124. A 12-year-old obese boy presents with a painful limp and limited internal rotation and abduction of the left hip. X-ray shows posterior displacement of the femoral epiphysis. What is the next step in management?
➔ Surgical pinning of the femoral epiphysis (Obese adolescent + hip/knee pain + limited internal rotation → Think of SCFE → Urgent fixation to prevent complications)
- Note: Pain may refer to the anterior thigh or knee despite normal knee exam
- Differential diagnosis:
○ Legg-Calvé-Perthes: Age 4–10, non-obese child with gradual onset hip pain → SCFE is older + obese + more acute
○ Transient synovitis: Post-viral, well-appearing child with normal X-ray → SCFE shows epiphyseal displacement
125. A 7-year-old boy presents with progressive limping and mild pain in the right hip and knee for several weeks. He has no history of trauma. On exam, there is limited internal rotation and abduction of the right hip. What is the diagnosis?
➔ Legg-Calvé-Perthes disease (Painless or mildly painful limp + limited hip motion in a boy age 4–10 → Think idiopathic avascular necrosis of the femoral head)
- Note: MRI is diagnostic
- Manage with → Activity restriction, PT ± bracing (surgery if severe)
126. A 5-year-old boy presents with a limp and right hip pain after a recent upper respiratory infection. He is afebrile, can bear weight, and has mildly limited hip motion. Labs show normal WBC, ESR, and CRP. What is the diagnosis?
➔ Transient synovitis (Post-viral limp with normal labs → Suggests benign inflammation of the hip)
- Note: Common in children following viral infection
- Treatment is → Supportive
- Differentiate from Septic arthritis:
○ Child is ill-appearing, febrile, and has ↑↑ ESR/CRP/WBC
○ Refuses to move joint completely
○ Requires urgent arthrocentesis + IV antibiotics
127. A 3-week-old infant is brought in for evaluation due to persistent head tilting to one side and a firm, non-tender mass over the sternocleidomastoid muscle. What is the most likely underlying cause?
➔ Birth trauma (Head tilt + SCM mass in neonate → Think birth trauma leading to congenital muscular torticollis)
- Note: Birth trauma (e.g., forceps/vacuum delivery) → SCM injury → fibrosis
- Treatment: Physical therapy/stretching → usually resolves
128. A 2-week-old girl is brought for a routine checkup. On exam, the left leg appears slightly shortened, and the left hip is unstable. What is the most appropriate next step to confirm the diagnosis?
➔ Hip ultrasound (Infant <4 months with suspected DDH → Ultrasound is preferred as femoral head is not yet ossified)
- Note: Diagnosis → Positive Barlow/Ortolani + Ultrasound if <4 months (X-ray if >4–6 months
129. A 2-year-old girl refuses to move her left arm after her father lifted her by the hands to get her out of bed. She keeps the arm slightly flexed and pronated.. What is the next step?
➔ Attempt hyperpronation of the forearm (No swelling + child holding arm immobile in pronation + traction injury → Think radial head subluxation)
- Note: Diagnosis is → clinical
- Two reduction methods: hyperpronation (preferred) or supination + flexion.
🏁 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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