Biliary atresia is obstruction of the biliary tree due to progressive sclerosis of the extrahepatic bile duct. Diagnosis is by blood tests, ultrasonography, liver biopsy, and hepatobiliary scan. Treatment is surgical.
The incidence of biliary atresia in the US is about 1/8,000 to 1/18,000 live births (1).
In most cases, biliary atresia manifests several weeks to months after birth, probably after inflammation and scarring of the extrahepatic (and sometimes intrahepatic) bile ducts. It is rarely present in premature infants or in neonates at birth (or is unrecognized in neonates). The cause of the inflammatory response is unknown. Several infectious organisms have been implicated, including reovirus type 3 and cytomegalovirus, but no definitive association has been noted. In addition, there may be a genetic component with defects in one of several genes (CFC1, FOXA2).
Cirrhosis, with progressive, irreversible scarring of the liver, can be present by 2 months of age if the defect is not treated.
- 1. Harpavat S, Garcia-Prats JA, Anaya C, et al: Diagnostic yield of newborn screening for biliary atresia using direct or conjugated bilirubin measurements. JAMA 323(12):1141–1150, 2020. doi: 10.1001/jama.2020.0837
Symptoms and Signs of Biliary Atresia
Infants with biliary atresia are jaundiced and often have dark urine (containing conjugated bilirubin), acholic stools, and hepatosplenomegaly.
By 2 to 3 months of age, infants may have poor growth with malnutrition, pruritus, irritability, and splenomegaly.
Untreated, hepatic fibrosis progresses to cirrhosis resulting in portal hypertension, abdominal distention resulting from ascites, dilated abdominal veins, and upper gastrointestinal bleeding resulting from esophageal varices.
Diagnosis of Biliary Atresia
- Total and direct bilirubin
- Liver tests
- Serum alpha-1 antitrypsin levels
- Sweat chloride test
- Abdominal ultrasonography
- Hepatobiliary scan
- Typically liver biopsy and intraoperative cholangiography
Biliary atresia is identified by an elevation in both total and direct bilirubin. The serum alpha-1 antitrypsin levels should be determined because alpha-1 antitrypsin deficiency is another relatively common cause of cholestasis. Tests that are needed to evaluate the liver include albumin, liver enzymes, prothrombin time/partial thromboplastin time (PT/PTT), and ammonia level. The sweat chloride concentration should also be determined to rule out cystic fibrosis. Frequently, additional testing is needed to evaluate for other metabolic, infectious, genetic, and endocrine causes of neonatal cholestasis. Elevated serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) levels, and gamma-glutamyl transferase (GGT) support the diagnosis of biliary atresia and exclude other rare causes of cholestasis (eg, progressive familial intrahepatic cholestasis type 2 [PFIC2]) that cause low GGT.
Abdominal ultrasonography is noninvasive and can assess liver size and certain abnormalities of the gallbladder and common bile duct. Infants with biliary atresia often have a small contracted gallbladder or one that cannot be seen. However, these findings are nonspecific. A hepatobiliary scan using hydroxy iminodiacetic acid (HIDA scan) should also be done; excretion of contrast into the intestine rules out biliary atresia, but lack of excretion can occur with biliary atresia, severe neonatal hepatitis, and other causes of cholestasis.
A definitive diagnosis of biliary atresia is made with a liver biopsy and intraoperative cholangiography. The classic histologic findings are enlarged portal tracks with fibrosis and bile duct proliferation. Bile plugs may also be noted in the bile ducts. Intraoperative cholangiography reveals the lack of a patent extrahepatic bile duct.
Prognosis for Biliary Atresia
Biliary atresia is progressive and, if untreated, results in cirrhosis with portal hypertension by several months of age, liver failure, and death by 1 year of age.
Treatment of Biliary Atresia
- Intraoperative cholangiogram
- Portoenterostomy (Kasai procedure)
- Frequently liver transplantation
Infants with presumed biliary atresia require surgical exploration with an intraoperative cholangiogram. If biliary atresia is confirmed, a portoenterostomy (Kasai procedure) should be done. Ideally, this procedure should be done in the first month of life. After this period, the prognosis significantly worsens. Postoperatively, many patients have significant chronic problems, including persistent cholestasis, recurrent ascending cholangitis, and failure to thrive. If cholestasis persists for ≥ 3 months postoperatively, referral to a transplant center should be considered. Prophylactic antibiotics (eg, trimethoprim/sulfamethoxazole or neomycin) are frequently prescribed for a year postoperatively in an attempt to prevent ascending cholangitis. Drugs that increase bile production (choleretic agents), such as ursodiol about 10 mg/kg orally 3 times a day, are frequently used postoperatively. Nutritional therapy including supplemental fat-soluble vitamins is very important to ensure adequate intake to support growth (1). Even with optimal therapy, about 50% of infants will develop cirrhosis and require liver transplantation.
Infants who cannot undergo portoenterostomy frequently require liver transplantation by 1 year of age.
- 1. Mouzaki M, Bronsky J, Gupte G, et al: Nutrition support of children with chronic liver diseases: A joint position paper of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition. J Pediatr Gastroenterol Nutr 69(4):498–511, 2019. doi: 10.1097/MPG.0000000000002443
- In most cases, biliary atresia manifests several weeks after birth, probably after inflammation and scarring of the extrahepatic (and sometimes intrahepatic) bile ducts.
- Infants are jaundiced and often have dark urine (containing conjugated bilirubin), acholic stools, and hepatosplenomegaly.
- By age 2 to 3 months, infants may have poor growth with malnutrition, pruritus, irritability, and splenomegaly.
- Diagnose using blood test results, ultrasonography, hepatobiliary scan, liver biopsy, and intraoperative cholangiography.
- Treatment is with portoenterostomy (Kasai procedure).
- Often, liver transplantation is subsequently required.
Drugs Mentioned In This Article
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|trimethoprim||No US brand name|