A baby develops visible jaundice within the first 24 hours of life. How should this be regarded?

Answer: E. As pathological until proven otherwise, needing urgent workup

Jaundice within 24 hours is pathological

Jaundice appearing within the first 24 hours of life is pathological until proven otherwise and warrants urgent investigation - it is commonly due to haemolysis (e.g. ABO/Rh incompatibility, G6PD deficiency, hereditary spherocytosis).

Why early jaundice is concerning

• Physiological jaundice does not appear before 24 hours; it typically peaks at 48-72 hours and resolves by about a week.
• Early-onset jaundice is unconjugated hyperbilirubinaemia, which can cross the blood-brain barrier and, at high levels, deposit in the basal ganglia and thalami causing kernicterus (bilirubin encephalopathy).

Causes of early-onset jaundice

• Physiological jaundice (after 24 h), delayed/inadequate breastfeeding, increased haemolysis (isoimmune ABO/Rh, G6PD, spherocytosis), polycythaemia, sepsis, Crigler-Najjar, increased enterohepatic circulation.

Clinical relevance

Prompt measurement of bilirubin and a haemolysis screen are needed for jaundice in the first 24 hours.