Neonatal jaundice

The baby is two days old and the sclerae are yellow. Most of the time that sentence is a benign physiological event and the parents go home reassured. Sometimes — and the whole exam topic hangs on knowing which times — it is the opening of a haemolytic, G6PD-driven, or isoimmune crisis that can deafen the child for life within hours. The skill is not "is the baby jaundiced"; it is "is this number safe for this gestation and this age in hours, in this infant, with these risk factors". That is the whole topic.^[1][3]

Overview and definition

Neonatal jaundice is the yellow discolouration of skin, sclerae and mucous membranes caused by deposition of bilirubin, almost always unconjugated (indirect). Visible jaundice appears at a serum bilirubin of roughly 80 to 100 micromoles per litre in term infants, and lower in preterm. The first distinction you make at the bedside is physiological from pathological, and the line that separates them is timing — when the jaundice started, how fast it is rising, and what is driving it.^[1][3]

The visible colour is the surface of a much deeper question: how much bilirubin is circulating, is it crossing the blood-brain barrier, and what is the trajectory. Most jaundice is unconjugated and the feared complication is kernicterus. A small but vital minority is conjugated (direct hyperbilirubinaemia) and the feared complication there is biliary atresia missed past the Kasai window. Never lump the two.^[1][6]

References14ShowHide

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2. [2]Slaughter JL, Kemper AR, Newman TB Technical Report: Diagnosis and Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation Pediatrics, 2022.PMID 35927519
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14. [14]Zhu S, Zhou L, Feng Y, et al. Understanding the risk factors for adverse events during exchange transfusion in neonatal hyperbilirubinemia using explainable artificial intelligence Front Pediatr, 2022.PMID 36180854