Choledocholithiasis in patients with normal serum liver enzymes

Retrospective chart review of 330 patients undergoing ERCP over a two-year period yielded five patients with choledocholithiasis whose serum liver enzyme and total bilirubin levels were repeatedly normal. All were female, three were elderly, and the gallbladder was in situ in three of the five, one of whom had a large gallbladder remnant. In four patients, the common bile duct was dilated (> 10 mm), whereas none had intrahepatic duct dilatation. Four patients had a prominent ampulla, and stone size varied widely. Each patient was managed with endoscopic sphincterotomy and stone extraction followed by cholecystectomy for the four patients with the gallbladder or its remnant in situ. This small series proves that common duct stones may exist in patients with repeatedly normal serum liver enzyme and total bilirubin levels. We hypothesize that marked dilatation of the common bile duct or gallbladder may serve as a pressure sump and blunt liver enzyme elevation. Normal liver enzymes should not dissuade one from performing cholangiography in patients with suspected choledocholithiasis.