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Pediatrics Exam: 80/20 High-Yield Hacks

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1. Developmental Milestones - Single Most-Tested Topic

• No social smile by 2 months
• No babbling by 12 months
• No single words by 16 months
• No 2-word phrases by 24 months
• Any regression at any age = investigate immediately

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2. Neonatology (Highest-Yield Single Chapter)

• Physiologic: starts day 2-3, peaks day 4-5, resolves by day 7-10
• Pathologic: appears in first 24 hours → think hemolysis (ABO incompatibility, G6PD)
• Rule: jaundice on day 1 = blood type mismatch until proven otherwise
• Treatment thresholds: phototherapy → exchange transfusion (nomogram-based)

• Hypoglycemia in newborn → check glucose in any jittery/lethargic newborn
• Sepsis: GBS most common <7 days; Listeria rare but tested
• Umbilical hernia vs. omphalocele vs. gastroschisis (know which closes spontaneously)

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3. Pediatric Infectious Disease - Memorize the "Classic Triads"

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4. Congenital Heart Disease - Pattern Recognition

• Tetralogy of Fallot (most common) - harsh systolic murmur, tet spells relieved by squatting
• Transposition of Great Arteries - cyanosis at birth, no murmur, "egg-on-a-string" CXR
• Truncus Arteriosus
• Tricuspid Atresia
• Total Anomalous Pulmonary Venous Return

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5. Pediatric Fluids and Electrolytes

• 0-10 kg: 100 mL/kg/day
• 10-20 kg: add 50 mL/kg/day for each kg above 10

• 20 kg: add 20 mL/kg/day for each kg above 20

• Mild (<5%): thirsty, normal exam
• Moderate (5-10%): dry mucous membranes, decreased skin turgor, tachycardia
• Severe (>10%): sunken fontanelle, mottled, no tears, delayed cap refill → IV bolus 20 mL/kg NS

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6. Hematology Buzzwords

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7. Vaccination Schedule - High-Yield Points Only

• Birth: Hep B
• 2, 4, 6 months: DTaP, IPV, Hib, PCV13, Rotavirus (oral)
• 12-15 months: MMR #1, Varicella #1
• 15-18 months: DTaP booster
• 4-6 years: MMR #2, DTaP #5, IPV #4
• 11-12 years: Tdap, HPV, MenACWY

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8. Neurology Quick Wins

• Febrile seizures: 6 months - 5 years, <15 min, no focal features → reassure; do NOT give prophylactic anticonvulsants for simple febrile seizures
• Absence seizures: Blank staring + 3Hz spike-wave on EEG → ethosuximide
• Infantile spasms (West syndrome): <1 year, salaam spasms, hypsarrhythmia on EEG → ACTH or vigabatrin
• Reye syndrome: Aspirin in a viral illness → hepatic encephalopathy + fatty liver (why you never give aspirin to children <12)

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9. The Meta-Hacks (Strategy Layer)

1. Question banks first, textbooks second. A 2024 PMC study showed the highest exam z-scores came from combining high-yield review materials + question banks. UWorld + Harriet Lane Handbook is the gold standard combination.
2. Do questions before "feeling ready." Reviewing questions wrong and reading the explanation beats passive reading by a wide margin.
3. Study in 15-20 topic blocks, not by organ system. Pediatrics exams mix topics within a single vignette - practice recognizing the pivot (e.g., "now the child develops renal failure" = HUS, not a separate topic).
4. Milestone questions are almost always about the red flag, not the normal. When the vignette gives you an "abnormal" child - always ask: is this 1 domain or 2+ domains? Isolated fine motor delay → occupational therapy. Two domains → refer to developmental pediatrician.
5. For congenital heart disease: If the baby is cyanotic and prostaglandin is given → it's a ductus-dependent lesion (TGA, pulmonary atresia, critical coarctation). This is a favorite "next step" answer.
6. For any pediatric "next step" question: The order is almost always - stabilize airway/breathing/circulation → diagnose → treat. Never jump to antibiotics without at least considering whether the airway is safe (epiglottitis is the classic trap).

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Topics to Deprioritize (Low Yield)

• Rare inborn errors of metabolism (know the few classic ones: PKU, galactosemia, maple syrup urine disease - just the triad)
• Exact vaccine lot numbers / cold chain specifics
• Rare genetic syndromes beyond the big 5 (Down, Turner, Klinefelter, DiGeorge, Williams)
• Ophthalmology minutiae

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Developmental milestones + Neonatal emergencies + Kawasaki/croup/epiglottitis triads + Congenital heart 5Ts + Holliday-Segar fluids + Febrile seizures + Vaccine contraindications + Question bank daily practice

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Pediatric "Triad" Diagnosis Patterns - Exam Q&A Master List

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HOW TO USE THIS

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TIER 1 - Highest Frequency (Appear in Almost Every Exam)

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1. Kawasaki Disease

Q trap: A child gets aspirin for Kawasaki. Is Reye syndrome a risk? Answer: No - aspirin here is given for its anti-inflammatory/antiplatelet effect at therapeutic doses under specialist guidance, not for a viral illness.

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2. Intussusception

1. Colicky, intermittent abdominal pain (episodes 10-15 min, intervals 15-30 min)
2. Palpable sausage-shaped mass (RUQ/right abdomen)
3. "Currant jelly" stool (blood + mucus - ischemic mucosa) - late and infrequent

Exam trap: "All three features are present in a minority of patients." The question will likely give you 1 or 2 features. Pain + vomiting in a 6-18 month old = think intussusception first.

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3. Hemolytic Uremic Syndrome (HUS)

1. Microangiopathic hemolytic anemia (schistocytes on blood film)
2. Thrombocytopenia
3. Acute kidney injury (oliguria, hematuria, rising creatinine)

Q trap: Should you give antibiotics for the STEC diarrhea? Answer: No - antibiotics increase Shiga toxin release and worsen HUS risk. Treatment is supportive.

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4. Henoch-Schönlein Purpura (HSP / IgA Vasculitis)

1. Palpable purpura (below the waist - buttocks, lower limbs; non-thrombocytopenic)
2. Arthritis (knees and ankles)
3. Colicky abdominal pain ± GI bleeding

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5. Pyloric Stenosis

1. Projectile, nonbilious vomiting after every feeding (1-6 weeks of age)
2. Palpable "olive" mass - firm, ovoid, 1-2 cm in epigastrium
3. Hypochloremic, hypokalemic metabolic alkalosis (from losing HCl in vomit)

Q trap: Vomiting is NONBILIOUS (obstruction is above ampulla of Vater). Bilious vomiting in a newborn = surgical emergency until proven otherwise (think malrotation/volvulus).

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TIER 2 - Frequently Tested

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6. Epiglottitis

1. Drooling
2. Dysphagia
3. Dyspnea (stridor, respiratory distress)
4. (+ Distress / high fever - often quoted as the actual 4th D)

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7. Croup (Laryngotracheobronchitis)

1. Barky/seal-like cough
2. Inspiratory stridor
3. Hoarseness

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8. Meningococcemia

1. Fever
2. Petechial/purpuric rash (non-blanching, trunk → spreading)
3. Meningismus (neck stiffness, photophobia)

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9. Shaken Baby Syndrome / Abusive Head Trauma

1. Subdural hematoma (SDH)
2. Retinal hemorrhages
3. Encephalopathy (altered consciousness, seizures)

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10. Meckel Diverticulum

1. Occurs in 2% of the population
2. Within 2 feet of ileocecal valve
3. Usually presents within first 2 years of life
4. (2 types of ectopic mucosa: gastric and pancreatic)
5. (2:1 male predominance)

1. Painless rectal bleeding (hematochezia)
2. Iron-deficiency anemia
3. Age <5 years

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11. Tetralogy of Fallot

1. VSD (ventricular septal defect)
2. Overriding aorta
3. Pulmonary stenosis (RVOT obstruction)
4. Right ventricular hypertrophy

1. Cyanotic infant
2. Harsh systolic murmur (LLSB)
3. "Tet spells" (paroxysmal cyanosis during crying/feeding → child squats to relieve)

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TIER 3 - Rarer but Classically Tested

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12. Hand-Schüller-Christian Disease (Langerhans Cell Histiocytosis)

1. Lytic skull lesions
2. Exophthalmos (orbital bone involvement)
3. Diabetes insipidus (pituitary/hypothalamus involvement)

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13. Prune Belly Syndrome (Eagle-Barrett / "Triad Syndrome")

1. Absent/deficient abdominal wall muscles
2. Bilateral cryptorchidism
3. Urinary tract abnormalities (dilated ureters, bladder, renal dysplasia)

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QUICK EXAM DRILL TABLE

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