Biliary Atresia

Background

• Biliary atresia (BA) is the obliteration or discontinuity of the extrahepatic and intrahepatic biliary system leading to obstructed bile flow and persistent cholestasis in neonates.
• It is the leading cause of liver transplant in young children.
• Multiple factors are theorized to play a role in the etiology including genetic causes, prenatal exposures to drugs or infections, or postnatal events such as infections, inflammatory processes, or vascular conditions.
• Complications may include biliary and liver fibrosis and cirrhosis, with subsequent portal hypertension.

Evaluation

• Suspect biliary atresia (BA) in any neonate with persistent or new jaundice > 14 days old.
  • Infants with biliary atresia may otherwise appear healthy and have light stools and dark urine.
  • Infants presenting at > 3 months old may also have evidence of progressive liver disease.
• Early blood testing includes total and direct bilirubin and evaluation for all causes of neonatal cholestasis.
• The diagnosis is supported by serum levels of direct (conjugated) bilirubin > 1 mg/dL (17.1 mcmol/L) when total serum bilirubin (TSB) is ≤ 5 mg/dL (85.5 mcmol/L) or > 20% of TSB if > 5 mg/dL.
• Supportive findings on abdominal ultrasound include:
  • a triangular cord sign, an absent gallbladder, or an absence of intrahepatic biliary ducts
  • an absence of structural abnormalities consistent with other diagnoses such as liver masses, choledochal cysts, biliary ductal dilatation, or choledocholithiasis
• Liver biopsy findings may include portal fibrosis, bile duct dilation, and bile plugs with canalicular and intracellular bile and periportal hepatocyte swelling from cholestasis.
• Make a diagnosis of BA when an intraoperative cholangiogram demonstrates obliteration of the biliary system, if the gallbladder is present, or with visualization of extrahepatic bile duct fibrosis and an atretic gallbladder during exploratory laparotomy.

Management

• Medical management without surgical intervention is uniformly fatal.
• Hepatoportoenterostomy (the Kasai procedure) is the standard initial operation for most infants with biliary atresia (BA).
  • It involves excision of the entire extrahepatic biliary tree, the creation of Roux-en-Y limb from proximal jejunum, and the attachment of distal end to liver hilus and proximal limb with end-to-side anastomosis to jejunum distal to transection site.
  • It is usually done as an open procedure, and survival with the native liver increases with a younger age at surgery.
• Aggressive nutritional support is necessary to improve outcomes following both the Kasai procedure and a liver transplant, including:
  • an increased caloric intake to 120-150 kcal/kg/day
  • high doses of fat-soluble vitamins (A, D, E, and K)
  • a low-salt diet and fluid restriction for children with ascites
• A liver transplant may be considered as the primary surgery for infants > 3 months old not likely to benefit from the Kasai procedure. A transplant should be considered after the Kasai procedure if the initial hepatoportoenterostomy is unsuccessful, or if either end-stage liver disease or other intractable conditions develop. A liver transplant is reported to eventually be performed in 67% of children with BA.