Assessment, Diagnosis, and Clinical Decision-Making
Diagnostic reasoning in pediatrics
Assessment questions reward a structured approach: chief complaint and history, age-specific vital signs, growth and developmental trajectory, focused exam, then a prioritized differential. Know normal variants (benign murmurs, physiologic reflux, genu varus and valgus) and red flags (lethargy, poor perfusion, respiratory distress, dehydration, bulging fontanel, petechiae, bilious vomiting). Use developmental milestones to identify delay and decide whether to screen, refer, or reassure.
Concepts to master
Understand pretest probability, sensitivity and specificity, and why a screening test needs a confirmatory test. Interpret growth charts using corrected age for preterm infants and recognize crossing percentiles as a warning. Recognize age-dependent fever thresholds and sepsis risk. Use validated tools for common concerns but remember tools support, not replace, clinical judgment.
Question traps
Trap answers often overreact to a benign finding, underreact to a subtle red flag, apply adult norms to children, or choose a diagnostic test before stabilization. Beware absolutes such as always and never, and answer choices that skip the focused history. In neonates and young infants, fever is a special case; in adolescents, confidentiality and mental health screening matter.
Worked example and rule of thumb
A 21-day-old with rectal temperature 38.0 C, poor feeding, and irritability needs urgent evaluation and sepsis workup, not home observation. Rule of thumb: age plus acuity plus red flags determine disposition before diagnosis.