Background/purpose: Despite extensive evaluation based on clinical history, biochemical tests, and noninvasive imaging studies, the cause of acute pancreatitis cannot be determined in 10 to 30% of patients, and a diagnosis of idiopathic acute pancreatitis is made. The purpose of this study was to clarify the pancreatographic findings in patients with idiopathic acute pancreatitis.
Methods: Endoscopic retrograde cholangiopancreatography (ERCP) was performed in 34 patients with idiopathic acute pancreatitis, and the pancreatographic findings were examined. Patency of the accessory pancreatic duct was examined by dye-injection endoscopic retrograde pancreatography (ERP) in 16 of the 34 patients.
Results: In 11 patients (32%), the following anatomic abnormalities of the pancreatic or biliary system were demonstrated: complete pancreas divisum (n = 5), incomplete pancreas divisum (n = 2), high confluence of pancreaticobiliary ducts (n = 2), choledochocele (n = 1), and giant periampullary diverticulum (n = 1). Pancreatographic findings were normal in 17 patients. Eleven of these patients were examined by dye-injection ERP, and all were found to have nonpatent accessory pancreatic duct.
Conclusions: Anatomic abnormality of the pancreatic or biliary system is one of the major causes of idiopathic acute pancreatitis. Closure of the accessory pancreatic duct may play a role in the development of idiopathic acute pancreatitis in patients with a normal pancreaticobiliary ductal system.