Neonatal Jaundice

Question 1

Aetiology of neonatal jaundice

• <24h
• >24h
• Persistent jaundice (>14 days)

Answer 1

• <24h (always considered pathological)
  
  • Sepsis (UTI & TORCH)
  • Haemolytic disorders
    
    • Rhesus incompatability
    • ABO incompatability
    • Glucose-6-phosphate dehydrogenase (G6PD) deficiency
      
      • RBCs susceptible to oxidative stress
    • Spherocytosis
      
      • Defective RBC membrane structural proteins
• >24h
  
  • ‘Physiological’ jaundice (<200µmol/L)
    
    • 1. ↑ bilirubin production in neonates due to shorter RBC lifespan
    • 2. ↓ bilirubin conjugation due to hepatic immaturity
    • 3. Absence of gut flora impedes elimination of bilirubin
• Persistent jaundice (>14 days)
  
  • Unconjugated
    
    • Breastfeeding
      
      • If feeding difficulties→ ↓ intake → dehydration → ↓ bilirubin elimination + ↑ enterohepatic circulation
    • Hypothyroidism
      
      • ↓ bilirubin metabolism
      • ↓ gastric motility → ↑ enterohepatic circulation
    • Sepsis (UTI & TORCH)
  • Conjugated (obstructive)
    
    • Biliary atresia
    • CF (viscous bile)
    • Galactosaemia
      
      • Impaired galactose metabolism → build up of toxic precursors → hepatic injury