Pediatric Infectious Diseases
Domain focus
Pediatric infectious diseases tests febrile infants, common respiratory and ear infections, immunization, and serious bacterial infection.
Core rules
- Febrile infant ≤28 days: full sepsis evaluation-blood, urine, CSF-and empiric antibiotics covering group B Streptococcus, E. coli, and Listeria (ampicillin plus gentamicin or cefotaxime). Add acyclovir if HSV risk.
- Fever without a source in 3–36 months: UTI is common; obtain a catheterized urine specimen before antibiotics.
- Acute otitis media: bulging tympanic membrane, ear pain, or otorrhea. High-dose amoxicillin (80–90 mg/kg/day) is first-line when antibiotics are indicated.
- Viral URI does not need antibiotics. Immunization is the most effective prevention for Haemophilus influenzae type b, pneumococcus, and measles.
- Kawasaki disease: fever ≥5 days plus conjunctivitis, mucositis, rash, extremity changes, or cervical adenopathy; treat with IVIG and aspirin.
Worked example
A 21-day-old has a temperature of 38.2°C, is fussy, and has no localizing signs. Reasoning: at this age, fever is a sepsis equivalent. Perform a full workup, including lumbar puncture if safe, and start empiric ampicillin plus gentamicin or cefotaxime after cultures. Do not send the infant home with antipyretics alone.
Traps
- Using a bag urine specimen to diagnose UTI.
- Treating a viral URI with antibiotics because the fever is high.
- Missing Kawasaki disease because the child has no rash at presentation.