Background : Biliary Ascariasis is the migration of the intestinal roundworm into the biliary tree. The incidences have been increasing worldwide due to the increased use of sonography in clinical practice. We studied the diagnostic accuracy of transabdominal ultrasonography in biliary ascariasis with either endoscopic retrograde cholangiopancreatography (ERCP) retrieval of live ascaris or ascaris carcass, and/or intraoperative biliary surgery findings of ascariasis as the reference standard.

Methods : A cross-sectional 12-year study in which data on patients diagnosed with biliary ascariasis who were admitted at our institution was analyzed. We collected findings on preoperative abdominal ultrasound, ERCP and biliary surgery.

Results : Out of the 121 patients with suspected biliary ascariasis, 82 patients were identified to have established the presence of biliary ascariasis. It was more common in females at 70% with a 2.3:1 female-to-male ratio. The most common presentation was upper abdominal colicky pain (95%). The presence of biliary ascariasis ultrasonographically was commonly noted as a tubular structure (95.86%) and mostly within the common bile duct (63%). Accuracy measures revealed that among the ultrasound characteristics, the finding of tubular structure within the biliary tree had 95.1% sensitivity in detecting patients suspected of biliary ascariasis. All other sonographic findings had low sensitivities as follows: intrahepatic ectasia (57.3%), extrahepatic ectasia (70.7%), dilated common bile duct (65.1%), and presence of mobility (24.3%).

Conclusions : This study concluded that transabdominal ultrasonographic finding of a tubular structure within the biliary tree is the recommended initial diagnostic for patients having biliary ascariasis.