Biliary Atresia

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Biliary atresia\: rare, congenital condition a
the extrahepatic ducts, leading to cholestasis, liver damage, and failure.
Incidence\: around 1 in 17,000 live births annually in the UK; most common cause of liver transplantation in children
worldwide.
Aetiology\: mostly unknown; believed to be multifactorial, involving genetic (e.g., C F C 1 , P K D 1 L 1 , A D D 3 , E F E M P 1 ), viral
infections (e.g., rotavirus, reovirus type 3), immune-mediated, and defects in morphogenesis.
Classi
Ohi system\:
Type I (~10%)\: patent proximal ducts, atresia of the common bile duct
Type II (~2%)\: atresia of the common bile duct and hepatic duct
Type III (~88%)\: atresia of almost all extrahepatic ducts, including the porta hepatis
Presentation\:
Isolated biliary atresia (most common)
Biliary atresia with other congenital anomalies (e.g., splenic malformation syndrome, polysplenia, situs inversus, cardiac
malformations, vascular anomalies)
Clinical features\:
History\: persistent neonatal jaundice beyond 14 days, pale stools, dark urine, possible bruising due to vitamin K de
Examination\: jaundice, hepatosplenomegaly, ascites, failure to thrive in infants over three months old.
Di
Obstructive jaundice causes\: choledochal cyst, cholelithiasis, spontaneous perforation of the bile duct, Allagile syndrome.
Other di
antitrypsin de
Investigations\:
Laboratory\: newborn blood spot screening, liver function tests (conjugated hyperbilirubinaemia, raised GGT).
Imaging\: ultrasound (triangular cord sign, hepatic artery changes, gallbladder ghost triad), hepatobiliary scintigraphy (HIDA
scan).
Other\: percutaneous liver biopsy (bile duct proliferation with bile plugs), operative cholangiography (gold standard).
Management\:
Early surgical treatment\: ideally by 45 days of life to avoid liver transplantation.
Kasai portoenterostomy\: removal of damaged bile ducts and replacement with a loop of intestine to allow bile
Liver transplantation\: required if Kasai procedure fails or due to progression of liver damage; indications include failure of
Kasai, growth retardation, portal hypertension, progressive liver dysfunction.
Antibiotic prophylaxis\: for the
Complications\:
Ascending cholangitis
Obstruction of the Roux-en-Y loop
Cirrhosis (can lead to hepatocellular carcinoma)
Portal hypertensionArticle 🔍
A comprehensive topic overview

Introduction

Biliary atresia is a rare, congenital condition that a
and
Biliary atresia usually presents in infants and young children and can be life-threatening if left untreated.
In the UK, the incidence is around 1 in 17,000 live births annually. 1
liver transplantation in children.
2
Worldwide, it is considered the most common cause of

Aetiology

The underlying cause for biliary atresia remains mostly unknown, but it is believed to be multifactorial, involving genetic
and acquired causes\:
2
Genetics\: a genetic predisposition is implicated as the condition seems more common in certain geographic areas.
Some gene mutations have been found to increase the susceptibility to developing biliary atresia (e.g. C F C 1 , P K D 1 L 1 ,
A D D 3 , and E F E M P 1 ) .
Viral infections\: a correlation between perinatal infection with rotavirus and reovirus type 3 and biliary atresia has been
shown in some studies in mice. These results are still debated and have yet to be con
Immune-mediated\: the above infections (or others) could trigger an autoimmune-like reaction perinatally which causes
cell death at the level of the bile duct.
Defects in morphogenesis\: biliary atresia has been linked to other congenital abnormalities. This could indicate that an
insult occurs at a critical point during embryological development leading to the malformation of the extrahepatic biliary
ducts.
Classi
Two classi
2
The Ohi system classi
Type I (~10%)\: patent proximal ducts but atresia of the common bile duct
Type II (~2%)\: atresia of the common bile duct and hepatic duct
Type III (~88%)\: atresia of almost all extrahepatic ducts, including the porta hepatis
Figure 1. Schematic representation of the
Ohi classi
Biliary atresia can also be classi
Isolated biliary atresia (most common)
Biliary atresia with other congenital anomalies\: the most common of these is the biliary atresia splenic malformation
syndrome, which is associated with polysplenia, situs inversus, cardiac malformations, and vascular anomalies.
3,4

Clinical features

HistorySymptoms of biliary atresia may not present until after the
develop.
2
Typically, infants present with persistent neonatal jaundice (beyond 14 days). The jaundice is usually associated with pale
stools and dark urine due to biliary obstruction. In addition, some infants may develop bruising due to vitamin K de
Clinical examination
The most common
In the later stages of the disease, usually seen in infants over three months old, clinical
5
Hepatosplenomegaly
Ascites
Failure to thrive\: due to malabsorption of fats

Di

Other causes of obstructive jaundice that can occur in the neonatal period include\:
2,5,7
Choledochal cyst
Cholelithiasis
Spontaneous perforation of the bile duct
Allagile syndrome\: a rare disorder where a baby is born with fewer bile ducts than normal
Other di
5
Cystic
Lipid storage disorders
Idiopathic neonatal hepatitis
Congenital infections
Alpha-1-antitrypsin (A1AT) de

Investigations

Laboratory investigations
Relevant laboratory investigations include\:
2,6,8
Newborn blood spot screening\: although this does not test for biliary atresia, it includes a test for cystic
di
2
Liver function tests (LFTs)\: will be abnormal with conjugated hyperbilirubinaemia and raised gamma-
glutamyltransferase (GGT)
5
NICE recommends that all children with neonatal jaundice have their bilirubin levels tested within 6 hours.
6
Physiological causes of jaundice can be di
unconjugated hyperbilirubinemia, whereas liver disease will cause conjugated hyperbilirubinemia.
8
Imaging
Ultrasound is recommended as the
5
Key ultrasound features of biliary atresia include\:
9
The triangular cord sign (Figure 2)\: an echogenic sign representing the
Hepatic artery changes, which will be mainly larger
Gallbladder ghost triad\: small/atretic gallbladder with a length less than 19 mm (Figure 3), irregular or lobular contour,
lack of smooth echogenic mucosal lining with an indistinct wallFigure 2. Positive triangular cord sign.
Figure 3. Atretic gallbladder
Hepatobiliary scintigraphy (technetium-99m) or hepatobiliary iminodiacetic acid HIDA scan can also be performed. In
biliary atresia, good hepatic uptake of the radioisotope will be seen (Figure 4), but there will be no evidence of biliary
excretion into the bowels at the 24-hour follow-up (Figure 5).
9Figure 4. Early imaging post radioisotope uptake.
Figure 5. Imaging at 24 hours post radioisotope – showing no excretion into the bowels.
Other investigations
The preferred diagnostic investigation is a percutaneous liver biopsy. 5
bile plugs.
2
It would typically show bile duct proliferation with
Operative cholangiography remains the gold standard investigation. However, it is only used if there is diagnostic
uncertainty before treatment.
3

Management

Patients with biliary atresia require early surgical treatment. 6
Ideally, surgery should be performed by 45 days of life as this
provides the best success rate and helps avoid liver transplantation.
2,5Surgical management
The surgical intervention of choice is the Kasai portoenterostomy.
5
This procedure involves removing the damaged bile ducts and replacing them with a loop of intestine to allow bile to

The porta hepatis is anastomosed (in a Roux-en-Y fashion) to a part of the jejunum at the level of the hepatic hilum (Figure
5). 5
The jejunum is then attached on the other end to the rest of the small intestine forming the Y-shaped connection.
It is important to note this procedure is not curative, and the disease can continue to progress in patients who have had
bile
3
Figure 6. Schematic representation of the
Kasai portoenterostomy.
Liver transplantation
If portoenterostomy fails, liver transplantation may be required. 5
Sometimes, a liver transplant may be required even after
a successful Kasai procedure due to the progression of liver damage. 2
Liver transplantation is avoided where possible to
allow the child to continue their growth and is only considered in cases of end-stage liver failure.
2
The indications for liver transplant are\:
10
Failure of the Kasai procedure and reappearance of symptoms
Growth retardation that is non-responsive to intensive nutritional support
Development of portal hypertension and its complications (variceal bleeding, ascites)
Progressive liver dysfunction marked by pruritus and coagulopathy
All patients will require antibiotic prophylaxis for the
2

Complications

The most common complications related to surgical intervention are\:
5
Ascending cholangitis\: would present with a recurrence of the initial symptoms (e.g. jaundice and pale stools)
Obstruction of the Roux-en-Y loop\: causing recurrent or delayed ascending cholangitis
Cirrhosis\: can eventually lead to hepatocellular carcinoma
Portal hypertension

References

Children’s Liver Disease Foundation. British Paediatric Surveillance Unit Survey on Biliary Atresia. 2021. Available from\: [LINK]
BMJ Best Practice. Biliary Atresia. 2020. Available from\: [LINK]
Li-Zsa Tan. Biliary atresia, Don't Forget the Bubbles, 2016. Available from\: [LINK]
Siddiqui AI, Ahmad T. Biliary Atresia. StatPearls [Internet]. Treasure Island (FL)\: StatPearls Publishing.Available from\: [LINK]
Patient UK. Biliary Atresia. 2022. Available from\: [LINK]
NICE CKS. Jaundice in the newborn. 2020. Available from\: [LINK]
National Institute of Diabetes and Digestive and Kidney Diseases. De
from\: [LINK]
Kelly DA, Davenport M. Current management of biliary atresia. 2007. Available from\: [LINK]Singh G, Yap J, Fortin F, et al. Biliary atresia. Radiopaedia.org. 2022. Available from\: [LINK]
Biliary Atresia. 2023. Available from\: [LINK]
Image references
Figure 2 and 3. Anjum Bandarkar. Biliary atresia - triangular cord sign. License\: [CC BY-NC-SA]
Figure 4 and 5. James Harvey. Biliary atresia. License\: [CC BY-NC-SA]
Figure 6. Sato et al. Electrohydraulic lithotripsy through a
right intrahepatic stones. License\: [CC BY-NC-ND]

Reviewer

Dr Eleftheria Konstantoulaki | MRCPCH
Consultant Paediatrician

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Contents

Introduction
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