Paediatrics: Neonatal jaundice

2021-03-09 12:00 AM

Jaundice is common (60% term, 80% preterm in the first week), and is usually unconjugated. Significant jaundice may indicate an underlying disease.

Neonatal jaundice

Jaundice is common (60% term, 80% preterm in first week), and is usually unconjugated. Significant jaundice may indicate an underlying disease. High serum unconjugated free bilirubin is neurotoxic and can cause kernicterus (deafness, athetoid cerebral palsy (CP), seizures).

Physiological jaundice

Common and appears after 24hr, peaks around day 3–4, and usually re-solves by 14 days. It is due to immaturity of hepatic bilirubin conjugation, but poor feeding (particularly in breastfed infants) can also contribute. Jaundice progresses in a cephalic-caudal direction.

Measure bilirubin (transcutaneous or serum) in babies with jaundice. Action is required when serum bilirubin (SBR) is above gestation and age cut-offs (e.g. >300µmol/l in term infant at 72hr) or rapidly rising.

Causes of elevated SBR 

Exaggerated physiological jaundice (e.g. preterm, bruising); sepsis; haemolytic disorders; hepatic disease.

Treatment of elevated SBR

  • Stop bilirubin rising to level that may cause kernicterus.
  • Treat any underlying cause, e.g. sepsis.
  • Start ‘blue light’ phototherapy (converts bilirubin to water-soluble form that can then be excreted in urine).
  • Use age/gestation specific charts to determine level to start phototherapy (see Fig. 6.2). Be aware of risk factors (family history, exclusive breast feeding, Rh or blood group incompatibility).
  • Measure SBR frequently (4–24-hourly depending on circumstances) and stop when falls below treatment level.
  • Ensure adequate hydration.
  • Cover eyes (phototherapy side effects: ‘fall’ or ‘rise temperature; eye damage; diarrhoea; dehydration; rash; separation from mother).
  • Exchange transfusion ± intravenous immunoglobulin (IVIG) if very high SBR (e.g. >450µmol/L in term infant at 48hr) or rapid rise (>8.5µmol/L/hr).
  • In the UK the National Institute of Clinical Excellence (NICE) has produced guidance on investigation and management of newborn jaundice (see Fig 6.2)—the full guideline also includes gestation specific treatment thresholds.

Jaundice in the first 24hrs

Assume it is pathological. Start phototherapy. Check SBR, FBC, direct Coombs test (DCT), and blood group. Consider septic screen/ TORCH.

Causes 

Haemolysis (e.g. Rh disease), red cell enzyme defects (e.g. G6PD deficiency), red cell membrane defects (congenital spherocytosis, elliptocytosis), sepsis, severe bruising.

Prolonged jaundice (>14 days in term infant; >21 days in preterm)

All infants require investigation and measurement of conjugated bilirubin. If conjugated hyperbilirubinaemia present, the further specialized investigation will be required. Ask about pale stools/dark urine.

Causes 

Breastfeeding (benign, self-limiting, and usually resolves by 12wks), enclosed bleeding (e.g. cephalhaematoma), prematurity, haemolysis, sepsis, hypothyroidism, conjugated jaundice, hepatic enzyme disorders (e.g. Crigler–Najjar Syndrome, Lucy–Driscoll disease).

Initial investigations 

SBR (total and conjugated), U&E, FBC, DCT, blood group, thyroid function test (TFTs), LFTs, and glucose.

Treatment  

Depends on the cause.  Rarely  phototherapy  is  beneficial,  e.g.

Crigler–Najjar Syndrome.

Conjugated jaundice (conjugated SBR >25µmol/L))

Stools may be clay-coloured in obstructive jaundice.

Causes 

Sepsis, TPN, biliary tract obstruction (e.g. biliary atresia, choledochal cyst), viral hepatitis; TORCH infections, α1-antitrypsin deficiency, cystic fibrosis, inspissated bile syndrome after haemolytic disease, galactosaemia, other inherited metabolic disease, idiopathic giant cell hepatitis.

Initial investigations 

As for prolonged jaundice. Further investigations include radiology, enzyme testing, viral serology, liver biopsy, histology.

Treatment 

Depends on the cause.