Conjugated jaundice and neonatal cholestasis: SAQ

This infant presents at six weeks with the pathognomonic triad of biliary atresia: acholic (pale, putty-coloured) stools, dark urine staining the nappy, and progressive jaundice in an infant who initially appeared well. The conjugated bilirubin fraction of 120 micromol per litre (67 per cent of total) confirms cholestasis, which is always pathological. The failure to thrive and firm hepatomegaly further support evolving liver disease. [1]

Question 1 (10 marks)

Outline your diagnostic approach and the specific investigations you would organise for this infant. [1]

The conjugated fraction is above 17 micromol per litre and more than 20 per cent of total, confirming cholestasis and triggering the full diagnostic panel. Alongside the bilirubin, send a full liver panel including alanine and aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, albumin, and coagulation studies. A high gamma-glutamyl transferase favours obstruction or biliary atresia over an intrahepatic cause. Check the coagulation profile urgently and give intravenous vitamin K 1 milligram if the international normalised ratio is prolonged, before any invasive procedure. [1]

Run the metabolic and infective panel in parallel: glucose for hypoglycaemia, ammonia if metabolic disease is plausible, a full septic screen, TORCH and urine cytomegalovirus polymerase chain reaction, alpha-1-antitrypsin phenotype and level, galactosaemia and tyrosinaemia markers, thyroid function, urine reducing substances, and alpha-fetoprotein. Imaging begins with a fasted abdominal ultrasound looking for a small or absent gallbladder and the triangular cord sign, but a normal ultrasound does not exclude biliary atresia. The definitive diagnostic test is an intraoperative cholangiogram, and a percutaneous liver biopsy showing bile-duct proliferation, portal fibrosis, and bile plugs supports the diagnosis of biliary atresia. [2]

Question 2 (10 marks)

Describe the management if biliary atresia is confirmed and explain the factors that determine outcome. [2]

Once biliary atresia is confirmed at cholangiography, the definitive treatment is a Kasai portoenterostomy performed at the same anaesthetic, excising the fibrotic extrahepatic bile-duct remnant at the porta hepatis and anastomosing a Roux-en-Y jejunal loop to the denuded liver surface. The operation must be performed as early as possible, ideally before 60 days of life, because native-liver survival falls steadily as the age at surgery increases. [3]

Postoperative medical management aims to maximise bile drainage and prevent complications. Ursodeoxycholic acid 10 to 20 milligrams per kilogram per day improves bile flow, and antibiotic prophylaxis against ascending cholangitis, typically oral trimethoprim-sulfamethoxazole, is continued for months because each cholangitis episode erodes native-liver survival. The START trial found no significant benefit of high-dose corticosteroids on native-liver survival, so their routine use is not evidence-supported. All cholestatic infants need nutritional support with a medium-chain triglyceride formula and fat-soluble vitamin supplementation. The dominant determinant of outcome is the age at Kasai operation: native-liver survival is best before 30 to 40 days and falls with each additional week, and about 70 to 80 per cent of biliary atresia patients ultimately require liver transplantation. [3]