John R. Gaughen, Jr., M.D.

October 05, 2005


Congenital biliary atresia manifests in the early neonatal period as jaundice. The disease, which represents congenital fibrosis of the extrahepatic biliary system, is divided into multiple types, depending on the location of the atresia. The gallbladder may be absent, hypoplastic, or normal, depending on the site of biliary atresia. The major differential diagnosis for biliary atresia is neonatal hepatitis (which may arise from idiopathic, infectious, metabolic, or toxic etiologies). For Boards purposes, rare diseases may also be included in this differential, including Alagille syndrome (arteriohepatic dysplasia). Ultrasound is often used in the initial evaluation for jaundice. Ultrasound is often normal. The "triangular cord" sign is a relative specific sonographic sign for biliary atresia but is not frequently seen. Hepatobiliary scintigraphy is the most sensitive imaging modality for evaluation of and differentiation between biliary atresia and neonatal hepatitis. Tc-99m labeled iminodiacetic acid derivatives (IDA) are currently used. IDA compounds are taken up and excreted by hepatocytes in a fashion similar to bilirubin and subsequently excreted through the biliary system into the duodenum. Phenobarbital can be used prior to the procedure (for 5 or more days) to augment hepatocellular function and increase the sensitivity and specificity of the test. Radiotracer uptake by the liver is usually prompt in biliary atresia, compared to delayed uptake seen in neonatal hepatitis. The hallmark scintigraphic finding of biliary atresia is lack of radiotracer excretion into the bowel by 24 hours. In contrast, neonatal hepatits can show delayed excretion, but radiotracer should be detected in the bowel by 24 hours. HIDA scans carry an excellentive sensitivity and specificity for biliary atresia. However, false positives may arise from patients with severe hepatocellular disease. Biopsy is needed for definitive diagnosis. Differentiation between biliary atresia and neonatal hepatitis is imperative because biliary atresia is a surgical urgency, while the hepatitis is treated medically. Biliary atresia patients surgically corrected after 2 months of age carry a much worse long-term prognosis than those treated before 2 months. Uncorrected biliary atresia has a progressive course with a 100% mortality rate. The most common reparative operative procedure for biliary atresia is the Kasai portoenterostomy procedure.

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