How do you differentiate physiologic jaundice from pathologic jaundice in a newborn?

• A. Physiologic jaundice appears after 24 hours, peaks day 2–3, and resolves by day 7–10; pathologic jaundice occurs within 24 hours or persists beyond 2 weeks
• B. Physiologic jaundice occurs within 12 hours and lasts several weeks
• C. There is no difference between physiologic and pathologic jaundice
• D. Pathologic jaundice resolves within 24 hours

Answer: (A)

Timing and duration are the clues. Physiologic jaundice is due to the newborn’s immature liver trying to conjugate bilirubin and commonly appears after 24 hours of age. It typically peaks around day 2 or 3 and resolves by about day 7 to 10 in healthy, term infants. Pathologic jaundice, on the other hand, appears much earlier—within the first 24 hours—and, if it’s in a term infant, tends to persist beyond about 2 weeks (longer in preterm infants). This pattern suggests an underlying problem, such as hemolysis from blood group incompatibility, infection, polycythemia, internal bleeding, or liver/metabolic issues, and it requires prompt assessment and potential treatment. So the onset after 24 hours with resolution by 7–10 days points to physiologic jaundice, while onset before 24 hours or persistence beyond 2 weeks signals pathologic jaundice.