Master Pediatrics
for USMLE Step 2 CK

Core Concepts

Pediatrics covers growth, development, and health from birth through adolescence. Key areas include well-child visits, vaccinations, developmental milestones, common childhood illnesses, and emergent conditions. Growth is monitored via standardized growth charts (weight, height/length, head circumference), while development is assessed using age-appropriate milestones. Prevention is central, with universal newborn screening and adherence to the CDC's immunization schedule being paramount. Common etiologies of illness often differ from adults (e.g., viral causes predominant in respiratory infections, genetic syndromes, congenital anomalies). Family-centered care and consideration of psychosocial factors are crucial.

Clinical Presentation

• Neonatal Jaundice: Yellow skin/sclera, direct hyperbilirubinemia is always pathologic.
• Bronchiolitis (RSV): <2 years, viral prodrome, wheezing, tachypnea, retractions.
• Croup (Laryngotracheobronchitis): Barking cough, inspiratory stridor, hoarseness, often viral.
• Asthma: Recurrent wheezing, cough (worse at night/with activity), shortness of breath, chest tightness.
• Febrile Seizures: 6 months - 5 years, generalized tonic-clonic seizure with fever, no CNS infection.
• Pyloric Stenosis: 2-8 weeks old, non-bilious projectile vomiting after feeds, often hungry post-emesis.
• Intussusception: 3 months - 3 years, sudden onset intermittent colicky abdominal pain, "currant jelly" stools, sausage-shaped abdominal mass.
• Hirschsprung Disease: Failure to pass meconium in first 24-48 hours, chronic constipation, abdominal distension.
• Appendicitis: Periumbilical pain migrating to RLQ, anorexia, nausea, vomiting, fever.
• UTI: Infants: fever without source, poor feeding, irritability. Older children: dysuria, frequency, urgency, enuresis.
• Kawasaki Disease: Fever >5 days + 4/5 criteria: conjunctivitis, rash, adenopathy, strawberry tongue/oral changes, hand/foot changes.
• Henoch-Schönlein Purpura (HSP): Palpable purpura (buttocks/legs), arthritis, abdominal pain, renal involvement (hematuria/proteinuria).
• Minimal Change Disease (Nephrotic Syndrome): Periorbital edema, ascites, generalized edema, frothy urine.
• Post-streptococcal Glomerulonephritis (PSGN): 1-3 weeks post strep infection, gross hematuria, edema, hypertension.
• Meningitis: Fever, lethargy, irritability, poor feeding, bulging fontanelle (infants); headache, stiff neck, photophobia (older children).

Diagnosis (Gold Standard)

Growth/developmental assessment uses CDC growth charts and standardized screening tools (e.g., ASQ-3). Newborn screening varies by state but typically includes metabolic disorders (e.g., PKU, congenital hypothyroidism, galactosemia), hemoglobinopathies (e.g., sickle cell disease), and cystic fibrosis. Specific gold standards include:
Pyloric Stenosis: Abdominal Ultrasound (target sign, elongated/thickened pylorus).
Intussusception: Abdominal Ultrasound (target/pseudokidney sign), Air Enema (diagnostic and therapeutic).
Hirschsprung Disease: Rectal Biopsy (absence of ganglion cells in submucosal and myenteric plexuses).
UTI: Urine Culture (from catheterized sample in infants/young children, midstream clean catch in older children).
Meningitis: Lumbar Puncture with CSF analysis.
Cystic Fibrosis: Sweat Chloride Test.
Lead Poisoning: Serum Lead Level.

Management (First Line)

Vaccinations: Adhere to ACIP/CDC schedule.
Bronchiolitis: Supportive care (hydration, nasal suctioning). Bronchodilators, steroids, and antibiotics are NOT recommended.
Croup: Dexamethasone (single oral dose) for mild-moderate; Racemic Epinephrine for moderate-severe stridor at rest.
Asthma: Albuterol (SABA) for acute exacerbations; Inhaled Corticosteroids (ICS) for long-term control.
Febrile Seizures: Reassurance, antipyretics (no proven benefit in preventing recurrence).
Pyloric Stenosis: Fluid/electrolyte resuscitation, then surgical pyloromyotomy.
Intussusception: Air enema (reduces 75-90%); surgical reduction if enema fails or peritonitis present.
Hirschsprung Disease: Surgical resection of aganglionic segment.
Appendicitis: Surgical appendectomy.
UTI: Empiric oral or IV antibiotics (e.g., Ceftriaxone, Cefixime, Bactrim) based on age/severity, for 7-14 days.
Kawasaki Disease: IVIG + High-dose Aspirin.
HSP: Supportive care. Steroids for severe abdominal pain or joint symptoms. Renal follow-up.
Minimal Change Disease: Oral corticosteroids (e.g., Prednisone).
PSGN: Supportive care (fluid restriction, diuretics for edema, antihypertensives for HTN).
Meningitis: IV antibiotics (Ceftriaxone + Vancomycin, add Ampicillin for neonates); Dexamethasone for H. flu type B.
Anaphylaxis: IM Epinephrine.

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