Sphincter of Oddi dysfunction in patients addicted to opium: an unrecognized entity

Background: Opiate-induced sphincter of Oddi dysfunction (SOD) as a clinical entity has not been described. Methods: Eight chronic opium addicts (all men, mean age 61.3 years, mean duration of addiction 24.75 years) presenting with pancreatobiliary pain and a dilated bile duct with or without dilated pancreatic duct on abdominal US were studied. All patients underwent ERCP and biliary sphincterotomy. In addition, pancreatic sphincterotomy was performed in 4 patients with a dilated pancreatic duct. Observations: At ERCP, the bile duct was dilated in 8 and pancreatic duct in 4 patients. There was delayed drainage of contrast (>45 minutes) from the bile duct in all 7 patients studied, whereas delayed drainage from the pancreatic duct (>9 minutes) was incidentally observed in 3 patients. In 6 patients followed after sphincterotomy for at least 2 years, there was marked relief of symptoms. Transabdominal US at 2 years follow-up revealed a normal bile duct in 5 and persistent albeit minimal dilatation in 1 patient. Acute pancreatitis developed in 4 patients after ERCP and sphincterotomy, which was fatal in one. No patient had any abnormality in the gallbladder on initial or follow-up transabdominal US. Conclusion: SOD in opium addicts is a distinct clinical entity, mainly seen in men in this population, that is characterized by a long history of opium addiction and the absence of prior cholecystectomy or associated gallstone disease. Most patients are seen with the classic clinical picture of SOD with marked long-term improvement in symptoms after endoscopic sphincterotomy.