Overview

• Jaundice in first 24 hours → always pathological. Typically due to physiological problems in the red blood cells or a cross-reaction with the maternal blood.
  • Causes → infection (TORCH), rhesus haemolytic disease (esp. if 2nd pregnancy - mother may have anti-D IgG antibodies that have crossed the placenta and caused fetal haemolysis), ABO haemolytic disease, hereditary spherocytosis, G6PD deficiency.
    • Rhesus disease is milder than ABO disease. In first pregnancy, fetus can not be affected by rhesus incompatibility but can be by ABO disease. (ABO incompatibility more common due to success of anti-D prophylaxis).
    • Coombs Test Positive → indicates haemolytic anaemia is immune-mediated (ie. rhesus haemolytic disease).
    • Hereditary Spherocytosis → spherocytes on blood film, coombs negative.
    • G6PD Deficiency → heinz bodies on blood film, coombs negative.
• Jaundice from 2-14 days → usually physiological. More commonly seen in breastfed babies.
• Jaundice after 14 days → perform prolonged jaundice screen. Includes conjugated and unconjugated bilirubin, DAT, TFTs, FBC and blood film.
  • Causes → biliary atresia (raised conjugated bilirubin), congenital hypothyroidism (screened for in guthrie test), galactosaemia, UTI, breast milk jaundice, prematurity, congenital infections (CMV, toxoplasmosis), sepsis.
    • Congenital Hypothyroidism → hypotonia, poor growth, prolonged neonatal jaundice, hypreflexia, developmental delay. Suspect if heel-prick test not performed (ie. from abroad).

Making Diagnosis

Clinical Features

• Bruising in the neonatal period can lead to raised bilirubin levels due to the breakdown of haemoglobin.
• Unconjugated bilirubin can cross BBB → kernicterus (lethargy, poor feeding, irritability, hypertonia, seizures, coma).

Investigations

• Transcutaneous Bilirubin → can be used to assess bilirubin levels in jaundiced babies who are >35 weeks gestation and >24 hours of age.
  • If found to be >250 mm/L, measure serum bilirubin levels.
• <24 Hours of age → serum bilirubin (as more likely to be pathological) urgently (within 2 hours).

<aside> 💡 <24hrs: serum bilirubin, 24hrs-2wks: transcutaenous bilirubin, >2wks: split serum bilirubin.

</aside>

Management Plan

• Physiolgical → reassurance and observation.
• Pathological Unconjugated ⇒
  • Acute Bilirubin Encephalopathy → immediate exchange transfusion.
  • Total Bilirubin >95th Centile for Phototherapy → phototherapy (recheck serum bilirubin within 4-6 hrs to assess response).
    • Conjugates bilirubin so it can be excreted in urine and faeces - ONLY WORKS ON UNCONJUGATED BILIRUBENAEMIA.
    • Monitor bilirubin levels every 4-6 hours when first starting, and then 6-12 hours when levels are stable or falling. Once >50 micromoles/L below treatment threshold, photherapy can be stopped. Recheck bilirubin in 12-18 hours to assess for a rebound hyperbilirubinaemia. If still >50 micromoles/L below, no further monitoring. If within 50 micromoles/L of treatment, recheck level again in 12 hours and consider restarting phototherapy.
    • If below treatment line but within 50 micromoles/L → recheck serum bilirubin in 18 hours.
  • Total Bilirubin >95th Centile for Exchange Transfusion → exchange transfusion.
• Pathological Conjugated → treat underlying cause (eg. surgery for biliary atresia).