Neonatal jaundice: unconjugated hyperbilirubinaemia: SAQ

This infant is a late-preterm (36 weeks) exclusively breastfed male with early visible jaundice and a bilirubin of 280 micromol per litre at 30 hours. The unconjugated fraction predominates (conjugated only 12 micromol per litre). The key concerns are the low gestational age, early onset relative to age, suboptimal feeding with 9 per cent weight loss, and maternal blood group O placing the infant at risk for ABO incompatibility. ^[1]

Question 1 (10 marks)

Outline your assessment and investigation plan for this infant. ^[1]

Begin with a structured clinical assessment. Confirm the timing of jaundice onset, the gestational age, feeding pattern, stool and urine colour, and family history. Examine the infant for pallor suggesting haemolysis, cephalohaematoma or bruising, hepatosplenomegaly, and general wellness. Plot the total serum bilirubin of 280 micromol per litre on the hour-specific nomogram for a 36-week infant. At 30 hours this bilirubin falls in the high-risk zone, warranting investigation and likely phototherapy. ^[2]

The investigation plan focuses on excluding haemolysis and identifying risk factors. Perform a direct antiglobulin test (DAT) to detect antibody-coated red cells. Check maternal and infant blood groups and Rh status to assess for ABO or Rh incompatibility. Obtain a full blood count with reticulocyte count to identify anaemia and compensatory erythropoiesis, and a peripheral blood film for spherocytes (suggestive of ABO incompatibility or hereditary spherocytosis). Consider G6PD assay if the family heritage is at risk, noting that false-negative results can occur during acute haemolysis. The conjugated fraction of 12 micromol per litre is reassuring, excluding conjugated hyperbilirubinaemia and biliary atresia. ^[3]