ABP Pediatric Infectious Diseases common mistakes
ABP Pediatric Infectious Diseases · Understand the traps and how to avoid them.
Selecting empiric antibiotics from adult-derived or 'broadest coverage' habits, such as giving ceftriaxone alone to a febrile neonate, instead of matching age-specific pathogens and weight-based dosing.
Adult-oriented frameworks and fear of missing resistant organisms overshadow neonatal and infant epidemiology, especially group B Streptococcus, Escherichia coli, and Listeria, as well as the pharmacokinetic differences of small children.
What to do instead
Before finalizing an empiric regimen, state the age band and its likely pathogens, then verify dose, interval, and route against a pediatric dosing reference; for neonates, include ampicillin plus gentamicin or cefotaxime when clinically indicated.
Using a single negative rapid antigen, Gram stain, or culture to exclude infection without accounting for pretest probability, specimen timing, and test sensitivity.
Rapid tests are widely available and fast, which encourages binary thinking; candidates forget that sensitivity varies by specimen, pathogen load, and recent antibiotic exposure.
What to do instead
Interpret every result against the clinical syndrome and the test's operating characteristics; repeat testing or add PCR/culture when pretest probability remains high, and document why a negative result is insufficient.
Assuming a child is fully immunized because a parent reports being 'up to date,' or failing to consider a vaccine-preventable diagnosis in a partially vaccinated infant.
Vaccine schedules have age-specific windows and catch-up rules, and diseases such as pertussis, measles, and pneumococcal disease still occur in undervaccinated or incompletely dosed children.
What to do instead
Obtain and review the actual immunization record, map each dose to the child's age and the recommended schedule, and keep vaccine-preventable disease in the differential until doses are verified.
Anchoring on bacterial sepsis in a neonate with microcephaly, rash, hepatosplenomegaly, or hearing loss and stopping the evaluation after blood and CSF cultures.
Early-onset neonatal sepsis dominates training, so congenital infections such as cytomegalovirus, syphilis, toxoplasmosis, and Zika are overlooked even when their findings overlap with or differ subtly from sepsis.
What to do instead
When congenital-infection features are present, add targeted testing such as CMV PCR on saliva or urine, syphilis serology, and toxoplasma IgM/IgG, plus neuroimaging, ophthalmologic examination, and hearing evaluation, with specialist involvement.
Failing to connect a specific immune defect to its characteristic pathogens, such as asplenia with encapsulated bacteria, chronic granulomatous disease with catalase-positive organisms, and terminal complement deficiency with Neisseria species.
The immunocompromised differential is often memorized as a list of organisms rather than as defect-to-pathogen pairs, so prophylaxis, immunization, and urgent empiric coverage are misdirected.
What to do instead
Build and use a defect-to-organism table that links each immune abnormality to prophylaxis, vaccine recommendations, and empiric coverage; ask which arm of the immune system is impaired before choosing antibiotics.
Choosing isolation precautions by diagnosis label rather than by transmission route, or failing to recognize when a disease requires airborne rather than droplet precautions.
Precautions are often memorized separately from clinical presentation, yet varicella, measles, tuberculosis, and pertussis each require different precautions and exposure management.
What to do instead
At admission, state the suspected transmission route and match precautions to it (standard, contact, droplet, or airborne); notify infection prevention about exposures and report notifiable diseases promptly.
Not obtaining a detailed travel, animal, food, and water exposure history, leading to missed malaria, endemic mycoses, or parasitic disease in a febrile child.
The differential becomes anchored on common pediatric pathogens, and geography or exposure is treated as optional background rather than as diagnostic data.
What to do instead
Ask a structured exposure history covering travel, immigration, animals, recreational water, undercooked foods, and soil contact; order targeted tests such as thick and thin blood smears, serology, or fungal antigen testing when indicated.
Applying one fever-without-source algorithm across all ages, or omitting age-specific testing such as a urine culture or evaluation for occult pneumonia in the appropriate age band.
Algorithms differ for neonates aged 0 to 28 days, infants aged 29 to 90 days, and older infants; candidates conflate low-risk criteria and skip essential tests.
What to do instead
State the age band first, then follow the corresponding evaluation pathway; document which low-risk criteria are met and confirm that urine, blood, and CSF testing are appropriate for the child's age and appearance.
Failing to consider tuberculosis or nontuberculous mycobacterial disease in a child with chronic cough, lymphadenitis, or failure to thrive, or misreading interferon-gamma release assay results in young children.
Tuberculosis is perceived as rare in high-resource settings, and IGRA interpretation in young children is nuanced because of limited sensitivity and inability to exclude infection.
What to do instead
Include tuberculosis in chronic or subacute presentations, obtain exposure history and chest imaging, interpret IGRA alongside age and pretest probability, and use culture or PCR and pediatric tuberculosis expertise when suspected.
Relying on IgM serology alone to diagnose acute viral infection, or ignoring the window period and persistence of IgM for viruses such as cytomegalovirus, herpes simplex virus, and Epstein-Barr virus.
Serology is familiar and widely available, but IgM can be falsely positive, persist for months, or appear after the acute window; PCR and paired sera are often more informative.
What to do instead
Choose the test by timing and purpose: PCR or antigen testing for acute infection, paired IgG for seroconversion, and avidity testing when timing matters; interpret IgM in the full clinical context rather than in isolation.