# Biliary Atresia > Biliary atresia for NEET-PG Paediatrics, covering conjugated jaundice, acholic stools, the triangular cord sign, HIDA scanning and Kasai surgery timing. - Canonical URL: https://prepelephant.com/topics/neet-pg/paediatrics/biliary-atresia - Exam / course: NEET-PG · Subject: Paediatrics - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-15 - Last updated: 2026-10-15 - Reference basis: Bailey and Love's Short Practice of Surgery; Nelson Textbook of Pediatrics - How to cite: "Biliary Atresia", PrepElephant, https://prepelephant.com/topics/neet-pg/paediatrics/biliary-atresia ## Direct answer Biliary atresia is progressive inflammatory obliteration of the extrahepatic bile ducts in early infancy, causing obstructive cholestasis that presents as prolonged conjugated jaundice with pale stools. If untreated, it progresses to biliary cirrhosis. The Kasai portoenterostomy, ideally performed before about 60 days of age, is the standard surgical treatment, and liver transplantation is needed when it fails. ## What you must remember - **Presentation:** conjugated jaundice beyond the first two weeks of life, with pale or acholic stools and dark urine. - **Biochemical threshold:** conventionally, a direct bilirubin above about 1 mg/dL, or above 20 per cent of total bilirubin, in a jaundiced infant warrants investigation. - **Triangular cord sign:** an echogenic triangular or tubular structure at the porta hepatis, representing the fibrous remnant of the ducts, with a small or absent gallbladder. - **HIDA scan:** technetium-labelled imaging shows hepatic uptake without excretion into the duodenum. - **Liver biopsy:** bile ductular proliferation and portal tract oedema support the diagnosis, though they are not diagnostic alone. - **Operative cholangiogram:** the definitive test, performed at laparotomy or laparoscopy, showing no flow of contrast into the duodenum. - **Kasai procedure:** hepatoportoenterostomy, with a jejunal loop anastomosed to the porta hepatis; outcome is best when performed before about 60 days. - **After surgery:** fat-soluble vitamins A, D, E and K, ursodeoxycholic acid, and vigilance for cholangitis. ## A diagnostic pathway for persistent jaundice A five-week-old infant has jaundice that has not settled, pale stools and a palpable liver edge. The steps below move from confirming the diagnosis to treating it before the surgical window closes. 1. **Confirm conjugated jaundice.** Measure the direct bilirubin fraction, and repeat it if the first sample is unclear. 2. **Exclude other causes.** Screen for infection, metabolic disorders such as galactosaemia, and alpha-1 antitrypsin deficiency. 3. **Image the biliary tract.** Ultrasound looks for the gallbladder and the triangular cord sign, and a HIDA scan is added if doubt remains. 4. **Confirm at operation.** Laparoscopy or laparotomy with an intraoperative cholangiogram is the definitive diagnostic step. 5. **Perform Kasai surgery.** Hepatoportoenterostomy, ideally before about 60 days, is the treatment of choice. 6. **Monitor after surgery.** Watch for cholangitis, poor bile drainage and fat-soluble vitamin deficiency. 7. **Plan transplant if needed.** Persistent jaundice or progressive liver disease despite Kasai leads to liver transplant referral. Outcome falls as surgery is delayed, so the diagnostic steps should run in parallel rather than one after another. Waiting for every investigation before deciding on surgery is the most common reason the window is missed. ## Where the exam tries to catch you Biliary atresia questions usually test timing and the difference from physiological jaundice. - **Trap:** attributing prolonged jaundice to physiological jaundice. **Correct:** physiological jaundice is unconjugated and usually resolves within the first two weeks, so conjugated jaundice beyond that is always pathological. - **Trap:** reassuring parents that pale stools reflect feeding. **Correct:** acholic stools with conjugated jaundice are a red flag for biliary atresia and need urgent referral. - **Trap:** delaying Kasai while awaiting extended genetic or metabolic tests. **Correct:** timing matters most, so the diagnosis should be made and surgery planned before about 60 days. - **Trap:** accepting a normal-looking ultrasound as excluding biliary atresia. **Correct:** a triangular cord with a small gallbladder supports the diagnosis, and the cholangiogram is the definitive test. ## Frequently asked questions ### Why do the stools become pale in biliary atresia? Biliary atresia blocks bile flow into the duodenum, so pigments do not reach the intestine and the stools become pale or acholic. Conjugated bilirubin that cannot be excreted spills into the urine, which turns dark. ### What is the triangular cord sign in biliary atresia? The triangular cord sign is an echogenic triangular or tubular structure at the porta hepatis on ultrasound, representing the fibrous remnant of the obliterated extrahepatic ducts. It supports the diagnosis in an infant with conjugated jaundice, but it is not diagnostic on its own. ### When is Kasai portoenterostomy performed in biliary atresia? Kasai portoenterostomy is performed as early as possible, ideally before about 60 days of age, because earlier surgery is associated with better bile drainage. Liver transplantation becomes the option if jaundice persists or recurrent cholangitis develops after the procedure. ### What direct bilirubin level suggests conjugated hyperbilirubinaemia in an infant? Conjugated hyperbilirubinaemia is conventionally suspected when direct bilirubin exceeds about 1 mg/dL, or is above 20 per cent of total bilirubin, in an infant with prolonged jaundice. Such a finding should prompt urgent investigation for biliary atresia.