Non-western patterns of biliary stones and the role of ascariasis.

Biliary calculi of a non-Western pattern were detected in 15 patients on real-time sonography performed over a 3-year period in a center serving a predominantly "Cape colored" (mixed race) population in South Africa. In two patients definite calculi were detected only in the common bile duct or gallbladder, but there was strong imaging and clinical evidence that the calculi were secondary to ascariasis. Twelve patients had intrahepatic calculi, predominantly left-sided, and evidence of past or present ascariasis. In at least five of the 12, biliary ascariasis was found at sonography or surgery. These fourteen patients reported recurrent, acute attacks of pain and cholangitis over a period of years. The symptoms were often difficult to distinguish clinically from those of uncomplicated intestinal or biliary ascariasis. The 15th patient had no evidence of ascariasis. Intrahepatic calculi were evenly distributed throughout both lobes and were clinically silent. Only one of the 13 patients with definite intrahepatic calculi had evidence of gallbladder calculi.