Neonatal jaundice: aetiology, diagnosis and treatment

A significant proportion of term and preterm infants develop neonatal jaundice. Jaundice in an otherwise healthy term infant is the most common reason for readmission to hospital. Jaundice is caused by an increase in serum bilirubin levels, largely as a result of breakdown of red blood cells. Bilirubin is conveyed in the blood as ‘unconjugated’ bilirubin, largely bound to albumin. The liver converts bilirubin into a conjugated form which is excreted in the bile. Very high levels of unconjugated bilirubin are neurotoxic. Phototherapy is a simple and effective way to reduce the bilirubin level. Most term babies have ‘physiological’ jaundice which responds to a short period of phototherapy, and requires no other treatment. A few babies have rapidly rising bilirubin levels which place them at risk of kernicterus. Current management of jaundice in the UK is guided by the NICE guideline. Any infant with high serum bilirubin or a rapidly rising bilirubin level needs to be treated urgently to avoid neurotoxicity. High levels of conjugated bilirubin in a term baby can indicate biliary atresia, and babies with persisting jaundice must have their level of conjugated bilirubin measured. Preterm infants on long-term parenteral nutrition may develop conjugated jaundice which generally improves with the introduction of enteral feed and weaning of intravenous nutrition.