RECENT PRINCIPLES ON SURGERY OF BILIARY ATRESIA

Abstract

iliary atresia is an idiopathic neonatal hepatobiliary disease characterized by progressive fibrosing obstruction of the extrahepatic biliary tree. The gross appearance of the extrahepatic biliary tract varies from an inflamed, hypertrophic occluded biliary tract to an atrophic remnant. Histologically, the liver has features of portal tract inflammation, with a sbridging fibrosis and ultimately biliary cirrhosis occurs. The lumen of the extrahepatic duct is obliterated at a variable level and this forms the basis for the commonest classification in clinical use - the japanese association of pediatric surgeons classification. Type 3 is the commonest (~90%) type and has the most proximal level of BA, atresia extends up to common bile duct, whereas in type 1 BA, atresia extends up to common hepatic duct level. An important variation is that of cystic change, seen in about 5% of cases, within some part of the extrahepatic biliary tract. Some cysts contain mucus, while others contain bile. If it is bile, there may be diagnostic confusion with that of a true choledochal cyst. In cystic biliary atresia, the wall is invariably thickened, lacks an epithelial lining and communicates poorly B  Summary 2 with abnormal non-dilated intrahepatic ducts. This should be evident at operative or percutaneous cholangiography. All patients with BA present with varying degree of jaundice, clay-colored stools and dark yellow urine. The severity of jaundice increases steadily and it is not unusual to find bilirubin levels around 20 mg% at the time of first presentation in developing countries. Failure to thrive, coagulopathy and anemia are also not uncommon. Some will present with signs of advanced disease and cirrhosis such as ascites, umbilical hernia, prominent abdominal veins and respiratory discomfort. In comparison to European or North American experience, most cases in developing countries present late. In a review of BA, only 5% cases were seen below 60 days of age, 40% between two and three months, 30% between three and four months and 25% presented beyond four months of age. Hepatomegaly was seen in all and 60% patients had a palpable spleen. The clinical diagnosis of BA is usually all too obvious in late-presenting cases. However, in infants of <60 days the diagnosis can be difficult. Key investigations include ultrasonography, biochemical liver function tests, viral serology, and a percutaneous liver biopsy. In some centers, duodenal intubation and measurement of intralumenal bile is the routine  Summary