BILIARY ATRESIA KASAI PORTOENTEROSTOMY

Biliary Atresia : Persistent conjugated hyperbilirubinemia (greater than 20% of total or 1.5 mg%) should be urgently evaluated. Initial evaluation should include a well-taken history and physical exam, partial and total bilirubin determination, type and blood group, Coomb's test, reticulocyte cell count and a peripheral smear. Cholestasis means a reduction in bile flow in the liver, which depends on the biliary excretion of the conjugated portion. Reduce flow causes retention of biliary lipoproteins that stimulates hypercholesterolemia causing progressive damage to the hepatic cell, fibrosis, cirrhosis and altered liver function tests. Biliary Atresia (BA) is the most common cause of persistently direct (conjugated) hyperbilirubinemia in the first three months of life. It is characterized by progressive inflammatory obliteration of the extrahepatic bile ducts, an estimated incidence of one in 15,000 live births, and predominance of female patients. The disease is the result of an acquired inflammatory process with gradual degeneration of the epithelium of the extrahepatic biliary ducts causing luminal obliteration, cholestasis, and biliary cirrhosis. The timing of the insult after birth suggests a viral etiology obtained transplacentally.

Almost 20% of patients have associated anomalies such as: polysplenia, malrotation, situs inversus, pre-duodenal portal vein and absent inferior vena cava. Histopathology is distinguished by an inflammatory process in several dynamic stages with progressive destruction, scar formation, and chronic granulation tissue of bile ducts. Physiologic jaundice of the newborn is a common, benign, and self-limiting condition.

In BA the patient develops insidious jaundice by the second week of life. The baby looks active, not acutely ill and progressively develops acholic stools, choluria and hepatomegaly. Non-surgical source of cholestasis shows a sick, low weight infant who is jaundiced since birth. The diagnostic evaluation of the cholestatic infant should include a series of lab tests that can exclude perinatal infectious (TORCH titers, hepatitis profile), metabolic (alpha-1-antitrypsin levels), systemic and hereditary causes. Total bilirubin in BA babies is around 6-10 mg%, with 50-80% conjugated. Liver function tests are nonspecific. Lipoprotein-X levels greater than 300 mg% and Gamma Glutamyl Transpeptidase (GGT) above 200 units% suggest the diagnosis. The presence of the yellow bilirubin pigment in the aspirate of duodenal content excludes the diagnosis of BA. Ultrasound study of the abdomen should be the first diagnostic imaging study done to cholestatic infants to evaluate the presence of a gallbladder, identify intra or extrahepatic bile ducts dilatation, and liver parenchyma echogenicity. The postprandial contraction of the gallbladder eliminates the possibility of BA even when nuclear studies are positive. Nuclear studies of bilio-enteric excretion (DISIDA) after pre-stimulation of the microsomal hepatic system with phenobarbital for 3-5 days is the diagnostic imaging test of choice. The presence of the radio-isotope in the GI tract excludes the diagnosis of BA. Percutaneous liver biopsy should be the next diagnostic step. The mini-laparotomy is the final diagnostic alternative. Those infant with radiographic evidence of patent extrahepatic biliary tract has no BA.

Medical management of BA is uniformly fatal. Kasai portoenterostomy has decreased the mortality of BA during the last 30 years. Kasai procedure consists of removing the obliterated extrahepatic biliary system, and anastomosing the most proximal part to a bowel segment. Almost three-fourth of patients will develop portal hypertension in spite of adequate postoperative bile flow. They will manifest esophageal varices, hypersplenism, and ascites. Hepatic transplantation is reserved for those patients with failed portoenterostomy, progressive liver failure or late-referral to surgery.