Neonatal Cholestasis
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Direct answer
Conjugated hyperbilirubinaemia beyond two weeks of age — a direct bilirubin over 1 mg/dL when total is under 5, or over 20 per cent of a total above 5 — is never physiological jaundice and always demands a structured work-up whose first goal is separating biliary atresia from intrahepatic disease, because the Kasai portoenterostomy works best before 60 days of life. Dark urine (bilirubin on dipstick) and pale or acholic stools with a firm growing liver point to biliary atresia; pigmented stools with systemic features point to intrahepatic disease — neonatal hepatitis, infections, PFIC and Alagille, alpha-1 antitrypsin deficiency, galactosaemia, tyrosinaemia and hypothyroidism. Fat-soluble vitamin replacement and medium-chain triglyceride nutrition support every cholestatic infant while the diagnosis is pursued.
What you must remember
- Definition to quote: direct bilirubin above 1 mg/dL if total is under 5 mg/dL, or more than 20 per cent of total when total exceeds 5 mg/dL; any direct component in a jaundiced newborn older than two weeks (three weeks in preterms) is pathological.
- The two-week rule: every infant still jaundiced at two weeks needs a split bilirubin — the commonest missed step in Indian practice.
- Biliary atresia signatures: pale or acholic stools, dark urine, firm smooth hepatomegaly; ultrasound triangular cord sign and absent or small gallbladder, hepatobiliary scintigraphy with no gut excretion, and intraoperative cholangiogram with liver biopsy confirming ductular proliferation.
- Kasai clock: portoenterostomy performed before 60 days gives the best native-bile drainage; outcomes fall steeply after 90-100 days, and half or more of operated children still eventually need transplantation — refer, do not observe.
- Screening panel on day one of work-up: fractionated bilirubin, liver function and gamma-glutamyl transferase, prothrombin time, thyroid function, galactosaemia screen (red blood cell galactose-1-phosphate uridyltransferase), urine for reducing substances and culture, toxoplasma-rubella-cytomegalovirus-herpes-syphilis serology, alpha-1 antitrypsin phenotype, and ultrasound — followed by liver biopsy where the picture is unclear.
- PFIC ladder: types 1 and 2 show low gamma-glutamyl transferase (type 3 high), with pruritus dominating; ursodeoxycholic acid, rifampicin and bile diversion precede transplant.
- Nutrition prescription: calories at 125 per cent of estimated needs with medium-chain triglyceride-enriched formula, and vitamins A, D, E and K — without them these infants bleed (K), develop rickets (D) and neuropathy (E).
- Ursodeoxycholic acid: standard adjunct in intrahepatic cholestasis at 15-30 mg/kg/day, contraindicated in biliary atresia and complete extrahepatic obstruction.
How to work through it
A six-week-old, deeply jaundiced with yellow-stained urine on the nappy and stools the mother describes as "clay-coloured" since birth. Sequence the answer: confirm direct hyperbilirubinaemia and coagulation (give vitamin K immediately — these infants bleed), examine the stool colour against a chart, and move fast: ultrasound for the triangular cord sign and gallbladder, then hepatobiliary scintigraphy and liver biopsy or intraoperative cholangiogram depending on centre protocol. If biliary atresia is confirmed at 45 days of life, the Kasai portoenterostomy this week offers the best chance of native bile flow; counsel about cholangitis prophylaxis, fat-soluble vitamins and later transplant probability.
The contrast case is the same age with equally deep jaundice but pigmented stools and a sepsis-like illness: cataracts with reducing substances in the urine point to galactosaemia (stop galactose instantly while awaiting the enzyme assay), whereas a thriving but intensely pruritic infant with a low gamma-glutamyl transferase points instead to progressive familial intrahepatic cholestasis. The discipline being tested is identical: classify direct from indirect first, then extrahepatic from intrahepatic, then treat the specific metabolic cause with a diet or drug while protecting nutrition.
How the exam frames it
The recurring question is the two-week jaundiced infant, and the expected first move is a fractionated bilirubin — not phototherapy, which delays the clock. Marks cluster on the direct bilirubin thresholds, the Kasai 60-day window, acholic stool identification, and the gamma-glutamyl transferase pattern separating biliary atresia and PFIC-3 (high) from PFIC-1/2 (low). The Indian perspective examiners add: mean age at presentation in Indian series is often beyond 90 days — the clinical answer being "work up anyway — late Kasai can still help", and the systemic answer being a split bilirubin at the two-week visit, which costs nothing.
Frequently asked questions
When is jaundice in an infant considered cholestatic?
When direct bilirubin exceeds 1 mg/dL with total under 5 mg/dL, or exceeds 20 per cent of a total above 5 mg/dL — any infant jaundiced beyond two weeks needs fractionation.
Why must biliary atresia be diagnosed before 60 days?
Kasai portoenterostomy achieves the best bile drainage and native-liver survival when performed before 60 days of life, with outcomes deteriorating sharply after 90-100 days.
Which stool and urine findings suggest biliary atresia?
Acholic or clay-coloured stools with dark yellow urine positive for bilirubin on dipstick, alongside firm hepatomegaly in an increasingly cholestatic infant.
Which metabolic cause of cholestasis requires immediate dietary change?
Galactosaemia — stop galactose (breast and cow milk) immediately on suspicion, confirm with erythrocyte galactose-1-phosphate uridyltransferase assay, as delay causes cataract, liver failure and sepsis.
Why give fat-soluble vitamins in cholestasis?
Bile flow failure impairs absorption of vitamins A, D, E and K, producing bleeding, rickets, neuropathy and deficiency states; supplement and monitor all cholestatic infants.