Effect of phenobarbital on serum and biliary parameters in a patient with Crigler-Najjar syndrome, type II and acquired cholestasis

The effect of phenobarbital treatment on bilirubin metabolism and bile secretion was studied in a patient with Crigler-Najjar syndrome, type II and acquired cholestasis. Following cholecystectomy and choledochostomy, a balloon inflatable T tube was inserted to facilitate bile collection. Hepatic UDP-glucuronyltransferase in surgically obtained liver tissue was 25% of normal activity and bilirubin monoconjugates accounted for >80% of the pigments in bile. Phenobarbital therapy decreased the concentration of fasting serum bile acids by 33% and partially reestablished their enterohepatic cycling postprandially. The total fasting serum bilirubin concentration (>90% unconjugated) increased 21% during phenobarbital treatment and was unaffected by caloric intake. Bile flow was increased 2.7 times after phenobarbital treatment. The biliary concentration of total bilirubin was increased 2.4 times, primarily due to monoconjugated bilirubin, which accounted for 91% of the biliary pigments. Bile acid, phospholipid, cholesterol, and calcium concentrations in bile were significantly increased after phenobarbital. The data indicate that even in the presence of cholestasis an underlying deficiency in bilirubin conjugation may be confirmed by biliary pigment analysis.