Introduction: Biliary obstruction, that affect around 5 cases per 1000 people in the united states, are due to several causes, with the Gallstones presenting the most common cause. Of parasitic causes, adult Ascaris lumbricoides, eggs of certain liver flukes (e.g. Clonorchis sinensis, Fasciola hepatica), echinococcosis, can obstruct the smaller bile ducts within the liver, resulting in intraductal cholestasis (1). Hydatid disease is a worldwide zoonosis produced by the larval stage of the Echinococcus tapeworm (2). In humans, hydatid disease involves the liver in approximately 60 to 75% of the cases (3). Echinococcal cysts of the liver can cause complications in about 40% of cases and manifest linically with acute abdominal pain. The most common complications in order of frequency are infection then rupture mainly into the biliary tree. Only 3-17% of the patients have a frank rupture, which has an overt passage of intracystic material to the biliary tract and, among hem, only 8 to 11% occur in the common bile duct (CBD) or cystic duct (4,5). We report this case of an abdominal pain due to an intrabiliary frank rupture of a hepatic hydatid cyst, occurring in the common bile duct causing a cholangitis. Case presentation 30 years lady presented with picture of cholangitis, found on ultrasound abdomen to have a cholelithiasis with dilation of common bile duct and possible CBD stone without abnormalities in the liver. While doing ERCP, incidentally a brown to white thick amorphous membrane was discovered in the common bile duct instead of a stone, that have been extracted by balloon technique. The finding raised the suspicion of a parasitic infection, so MRCP was done that showed remnant of complicated hydatid cyst in the right hepatic lobes. Discussion: Based on the previous results, an intrabiliary ruptured hydatid cyst of the liver was suspected in the common bile duct, causing an bstructive jaundice/cholangitis due to the intracystic hydatid material (membrane) that was found on ERCP. In front of an obstructive jaundice, the first test to do is an ultrasound abdomen to differentiate intra and extrahepatic causes of cholestasis according to the presence or absence of bile duct dilation. Once choledocholithiasis suspected, ERCP should be done to drain the common bile duct. (6) Most patients with Echinococcosis infection are asymptomatic and hydatid cyst is discovered incidentally during imaging. However, in around 25% of the cases, patient presents with an obstructive jaundice due to the rupture of hepatic hydatid cyst into the biliary tree (7). The diagnosis of Echinococcosis is usually established by radiologic tests and serology (8). ERCP is indicated when the results of these tests are unconclusive in patients with biliary colic associated with cholangitis. 3 different aspects may be seen on ERCP: round lucent filling defects due to daughter cysts or filiform wavy material in the common bile duct due to laminated hydatid membranes or brown thick amorphous membrane also due to hydatid membranes (9). Treatment of hydatid disease usually involves a combination of an anti-helminthic therapy and surgical resection / percutaneous aspiration of the cyst with endoscopic treatment in some cases (10,11,12). Conclusion: Physician must raise attention about parasitic disease-causing abdominal pain in the mergency departments. The diagnosis of abdominal parasitosis can be delayed because of the clinical similarities with other more frequent causes of abdominal pain. US abdomen may miss the diagnosis of a hydatid cyst due to several factors (obesity, location of the cyst, and the physician skills). A hydatid cyst may rupture in the biliary tract with migration of intracystic material into the CBD, such as hydatid membranes, mimicking CBD stone on US and leading to an obstructive jaundice / cholangitis.
