Pancreatic duct ascariasis: Case series

BACKGROUND AND OBJECTIVES: Although uncommon in the West, Ascaris lumbricoides is a common cause of acute pancreatitis in developing countries. The mechanism of acute pancreatitis in ascariasis may be due to obstruction of papilla of Vater, invasion of common bile duct (CBD), or pancreatic duct (PD). The invasion of PD occurs rarely owing to its smaller caliber. Ultrasonography (USG) is an effective tool for the diagnosis of biliary and pancreatic ascariasis; however, the diagnosis may be false negative in up to 30% of cases. Pancreatic ascariasis is a rare entity. We present our retrospective data of last 10 years of 15 cases of pancreatic ascariasis. METHODS: During a study period of 10 years, 15 cases of pancreatic ascariasis were diagnosed by USG/endoscopic ultrasonography (EUS). EUS was performed with a linear or radial echoendoscope. Thirteen patients presented with symptoms of acute pancreatitis. Out of 13 patients, nine presented with first episode of idiopathic pancreatitis while four presented with idiopathic recurrent acute pancreatitis. One patient had biliary colic and one patient presented with acute cholangitis. Twelve patients had mild pancreatitis while only one had moderate pancreatitis. Only two cases were diagnosed with USG while 13 patients were diagnosed with EUS. Out of 15 patients, 14 underwent side viewing endoscopy with removal of live single/multiple worms with rat tooth forceps/biopsy forceps/dormia basket in 13 patients. Two patients were managed conservatively with repeat USG showing absence of ascariasis. There were no complications. RESULTS: Two patients had associated bile duct ascariasis. EUS features were single or multiple linear hyperechoic structure without acoustic shadowing in the PD or CBD or with central hypoechoic tube, representing alimentary canal of the worm and movements of worms inside the duct. Live roundworms were removed from CBD and PD without undertaking sphincterotomy. In endemic areas, sphincterotomy facilitates the risk of migration of worms into the CBD. CONCLUSION: Ascariasis-induced acute pancreatitis is mild and EUS is the investigation of choice. The recurrence is rare and treatment is side viewing endoscopy with removal of worms. Although USG is quite sensitive for diagnosing biliary and pancreatic ascariasis, its sensitivity significantly falls when the worm is thin, in the PD, or the CBD is non-dilated. EUS should be used early in the workup of idiopathic acute pancreatitis after the first episode.