The usefulness of microscopic bile examination in patients with suspected microlithiasis: a prospective evaluation.

Gallbladder bile collected by duodenal intubation or during surgery was examined microscopically in patients who were free of stones and in patients with proven stones. None of the 16 patients free of stones had cholesterol monohydrate crystals or calcium bilirubinate granules in bile. Among the 17 patients with proven cholelithiasis, 13 with cholesterol stones had cholesterol monohydrate crystals in their bile, but only 2 of the 4 patients with pigment stones had calcium bilirubinate granules. These data confirm that cholesterol monohydrate crystals are sensitive and specific for cholesterol stones, whereas calcium bilirubinate granules lack sensitivity for the diagnosis of pigment stones. From these results, the diagnostic usefulness of microscopic examination of bile collected from the duodenum was studied prospectively in 46 patients with symptoms suggestive of cholelithiasis but in whom stones had not been visualized at cholecystography and ultrasonography. In 15 of them, bile was found to be abnormal: cholesterol monohydrate crystals were seen in 11, cholesterol crystals + calcium bilirubinate granules in 2 and calcium bilirubinate granules in 2. To date, nine of these patients have been operated on: 6 (all with cholesterol monohydrate crystals) had small cholesterol gallstones and 3 (2 with cholesterol monohydrate crystals and 1 with calcium bilirubinate granules) had signs strongly suggestive of the recent migration of gallstones. One patient refused operation, but minute pigment stones were found to be associated with calcium bilirubinate granules at duodenal intubation. In the other 31 patients, bile contained neither cholesterol monohydrate crystals nor calcium bilirubinate granules. They were not operated on and were followed up with repeated investigations for 12 to 24 months.(ABSTRACT TRUNCATED AT 250 WORDS)