Quick revision of bilirubin:
Bilirubin is the breakdown product of haem (which is from haemoglobin in red blood cells). As old red blood cells pass through the spleen, they get broken down into unconjugated bilirubin. This then goes to the liver where it conjugates with the glucuronic acid which makes it water soluble conjugated.
Most newborn infants become clinically Jaundice.
This is due to a combination of increased red cell breakdown and immaturity of the hepatic enzymes. This results in an unconjugated hyperbilirubinaemia. This is exacerbated by dehydration if establishment of feeding is delayed.
Onset of Jaundice within the first 24hours of life is always pathological.
Recognition and treatment of severe neonatoal unconjugated hyperbilirubinaeima is important to avoid kernicterus.
Kernicterus: brain damage due to deposition of bilirubin in the basal ganglia.
Prolonged neonatal jaundice might be due to liver disease if it is a conjugated hyperbilirubinaemia accompanied by:
- pale stools
- dark urine
- bleeding tendency
- failure to thrive
So if there is prolonged neonatal jaundice (more than three weeks) check whether it is conjugated hyperbilirubinaemia – this makes it likely to be due to liver disease.