Biliary ascariasis: an uncommon cause for recurrent biliary colic after biliary sphincterotomy and common bile duct stone removal

Case report

A 32-year-old woman, who had undergone laparoscopic cholecystectomy 18 months previously for gall bladder stones presented with biliary colic. An abdominal ultrasound was performed and it revealed an 8-mm calculus in the distal common bile duct (CBD). She underwent endoscopic retrograde cholangiography (ERC) with biliary sphincterotomy and CBD calculus was removed. Post ERC, a balloon occlusion cholangiogram was performed and it confirmed complete clearance of CBD calculus. She was asymptomatic for 1 week but thereafter again presented with recurrence of biliary colic. There was a possibility of small retained CBD calculus and a radial endoscopic ultrasound (EUS) examination of the biliary system was done. To our surprise, radial EUS showed a linear hypoechoic structure with hyperechoic margins, measuring 4 mm in width, inside the CBD and the CBD was mildly dilated (6.9 mm) (Figure 1, panel 1). We repeated the ERC and found a linear filling defect in the cholangiogram (Figure 1, panel 2). Balloon sweep extruded an adult round worm (Ascaris lumbricoides) partly outside the CBD (Figure 1, panel 3). It was removed with biopsy forceps and it measured 10 cm. OPEN IN VIEWER

Recurrent biliary colic in patients after cholecystectomy and CBD clearance is usually due to small CBD stones that are missed or recurring. In our case, the balloon occlusion cholangiogram was normal and the chance of missing large stones was less. EUS is a reliable investigation in such situations where small calculi or biliary sludge can be identified. ¹ Round worms sometimes enter the CBD and cause biliary colic.^2,3 Round worms inside the CBD can cause obstructive jaundice and can even present with cholangitis. Sphincterotomy facilitates easy access of the worm into the biliary system. These worms can also enter the gall bladder or the pancreatic duct resulting in cholecystitis or acute pancreatitis.^4,5 Our report re-emphasises that while evaluating biliary colic in areas endemic for ascariasis, the possibility of biliary ascariasis should always be considered. With the high incidence of biliary or pancreatic ascariasis post sphincterotomy, we recommend routine administration of prophylactic antihelminthics in endemic areas after biliary or pancreatic sphincterotomy.