🌞 Neonatal Jaundice & Biliary Atresia

🔑 Key Learning

• Neonatal jaundice affects >50% of babies and is often physiological
• Jaundice <24 hours old is pathological until proven otherwise
• High levels of unconjugated bilirubin risk kernicterus and permanent neurological damage
  • Phototherapy and exchange transfusion are mainstays of treatment if bilirubin exceeds thresholds
• Biliary atresia is a rare but serious cause of cholestatic jaundice with pale stools and dark urine
  • Early recognition of biliary atresia is critical — surgery is time-sensitive

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🧬 Pathophysiology of Neonatal Jaundice

• Neonates have:
  • High red cell mass with short RBC lifespan (~70 days)
  • Immature hepatic conjugation systems
• Result: Accumulation of unconjugated bilirubin

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📊 Epidemiology

• 50% of term neonates develop jaundice in the first week
  
• More common and prolonged in preterm infants

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🦠 Causes of Neonatal Jaundice

☀️ Physiological Jaundice

• Cause: Immature liver conjugation + short RBC lifespan
• Timing: Appears after 24 hrs, peaks day 3–4, resolves by 2 weeks
• Benign and self-limiting

🤱 Breast Milk Jaundice

• Cause: Unclear, thought to be due to breast milk compounds affecting bilirubin metabolism
• Timing: Starts day 2–4, peaks after 1–2 weeks, may persist up to 3 months
• Baby is well and thriving
• Benign and self-limiting

⚠️ Pathological Jaundice

• Timing: Jaundice <24 hrs, jaundice in unwell neonate
• Causes include:
  • Haemolysis: Rhesus, ABO incompatibility, G6PD deficiency, hereditary spherocytosis
  • Infection/Sepsis: e.g. UTI, may impair hepatic function
  • Dehydration: from poor feeding
  • Bruising: e.g. cephalohaematoma
• Risk of rapid rise in bilirubin → bilirubin encephalopathy → kernicterus

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👂 Clinical Features of Bilirubin Encephalopathy

Why is jaundice important?

• Unconjugated bilirubin is able to pass through the BBB and cause bilirubin encephalopathy. 
• Chronic bilirubin encephalopathy can result in complications

🧠 Acute Phase

• Lethargy, poor feeding
• High-pitched cry
• Hypertonia, opisthotonos
• Seizures

🧠 Chronic Phase (Kernicterus)

• Cerebral palsy
• Developmental delay
• Sensorineural deafness
• Learning difficulties
• Persistent seizures

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🧪 Investigations

• Clinical assessment with bilirubin level plotted on treatment chart
• Infection screen
• Haemolysis screen: Blood group, Coombs test, G6PD assay
• Liver function tests (LFTs)

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💊 Management of Neonatal Jaundice

• Physiological / breast milk jaundice: No treatment unless bilirubin exceeds threshold on treatment chart
• Treat underlying cause where appropriate (e.g. UTI, dehydration)
• Phototherapy (Blue light):
  • Converts unconjugated bilirubin to water-soluble pigment
  • Monitor bilirubin 4–6 hourly
  • Stop once bilirubin < threshold
• Exchange transfusion:
  • Indicated for dangerously high bilirubin
  • Poor response to phototherapy or signs of encephalopathy

    

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🚫 Biliary Atresia

🧬 Pathophysiology

• Obstruction or absence of bile ducts → cholestatic jaundice, bile retention, cirrhosis
• Progressive liver damage if untreated

👀 Clinical Features

• Presents age 2–6 weeks
• Prolonged jaundice with:
  • Pale stools
  • Dark urine
  • Hepatosplenomegaly
  • Abdominal distension

🧪 Investigations

• Liver biopsy: bile duct proliferation, bile plugs
• Cholangiogram: confirms diagnosis

💊 Management

• Kasai portoenterostomy: Connects liver to bowel to drain bile
  • Best if done before 8 weeks of age
• If late or unsuccessful → liver transplant required

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📝 Exam Clues & Clinchers

• Jaundice <24 hrs → pathological until proven otherwise
• Jaundiced, pale stools + dark urine → consider biliary atresia
• Breast-fed baby, thriving, jaundice lasting weeks → breast milk jaundice
• Neonatal jaundice - check bilirubin and compare to treatment chart → phototherapy
• Kernicterus = yellow staining of brain from unconjugated bilirubin