Conjugated jaundice and neonatal cholestasis: Viva

Branch 1: The decision to investigate

The candidate should immediately identify that reassurance without a conjugated bilirubin is unsafe. Jaundice persisting beyond two weeks in a term infant mandates a split bilirubin measurement. Breast-milk jaundice is a diagnosis of unconjugated hyperbilirubinaemia only and cannot be invoked until a conjugated fraction has been measured and found normal. The candidate must ask about stool and urine colour directly, because acholic stools or dark urine would make cholestasis and biliary atresia the leading concern. [1]

The conjugated fraction threshold is a conjugated bilirubin above 17 micromol per litre or more than 20 per cent of the total bilirubin. A result in this range confirms cholestasis, which is always pathological and triggers the full diagnostic panel. The candidate should explain that the single most avoidable error in neonatal cholestasis is reassurance without a split bilirubin, because it may delay a Kasai operation into the range where it cannot succeed. [1]

Branch 2: The diagnostic pathway

If the split bilirubin confirms cholestasis, the candidate should outline the parallel workup: a full liver panel including gamma-glutamyl transferase, coagulation studies, glucose, a septic screen, TORCH and urine cytomegalovirus polymerase chain reaction, alpha-1-antitrypsin phenotype, galactosaemia and tyrosinaemia markers, thyroid function, urine reducing substances, and alpha-fetoprotein. Coagulopathy from vitamin K deficiency must be corrected with intravenous vitamin K 1 milligram before any invasive procedure. [1]

Imaging begins with a fasted abdominal ultrasound, but the candidate must stress that a normal or even visible gallbladder does not exclude biliary atresia. The definitive diagnostic test is an intraoperative cholangiogram, and a liver biopsy showing bile-duct proliferation, portal fibrosis, and bile plugs supports the diagnosis. Early referral to the regional paediatric hepatology and surgical centre is essential because the timing of the Kasai operation depends on rapid transfer. [1]

Branch 3: Surgery and prognosis

If biliary atresia is confirmed, the definitive treatment is a Kasai portoenterostomy performed as early as possible, ideally before 60 days of life. The candidate should explain that native-liver survival is highest when surgery is performed before 30 to 40 days and falls with each additional week of delay, which is the rationale for stool-colour screening and for urgent referral. [2]

Postoperatively, the candidate should discuss ursodeoxycholic acid to improve bile flow, antibiotic prophylaxis against ascending cholangitis, and nutritional support with a medium-chain triglyceride formula and fat-soluble vitamins. The START trial found no significant benefit of high-dose corticosteroids on native-liver survival at two years, so their routine use is not evidence-supported. Liver transplantation is the salvage therapy for a failed Kasai, and biliary atresia is the leading indication for paediatric liver transplantation worldwide, with about 70 to 80 per cent of patients ultimately requiring it. [3]