EUS for detection of occult cholelithiasis in patients with idiopathic pancreatitis

Background: The aim of this study was to evaluate the use of endoscopic ultrasonography (EUS) in detecting occult cholelithiasis and determining a probable etiology in patients classified as having idiopathic pancreatitis by conventional radiologic methods. Methods: A prospective study was performed in 89 consecutive patients with acute pancreatitis. Transcutaneous ultrasonography (US), CT, or both was performed on all patients within 24 hours of admission. Endoscopic retrograde cholangiopancreatography (ERCP) was performed in all patients with confirmed or suspected biliary pancreatitis. EUS was performed in patients classified as having idiopathic pancreatitis. Results: Cholelithiasis was identified in 64 patients (72%) by conventional radiologic methods. Eighteen patients (20%) were classified as having idiopathic pancreatitis after evaluation by US (all 18 patients), repeated US (9 patients), CT (6 patients) and ERCP (13 patients). EUS performed in these 18 patients revealed small gallbladder stones (1 to 9 mm) in 14 patients; 3 were found to have concomitant choledocholithiasis. All stones were confirmed by subsequent ERCP and cholecystectomy. The remaining 4 patients in whom no etiology was identified had no clinical or radiologic evidence of cholelithiasis at a median follow-up of 22 months. Conclusion: Cholelithiasis is detected by EUS in a large number of patients classified as having idiopathic pancreatitis by conventional radiologic examinations. With identification of a biliary cause of acute pancreatitis, treatment can be initiated early, thereby reducing the risk of recurrent pancreatitis with its associated morbidity and mortality. EUS is a valuable diagnostic modality in the management of patients with acute pancreatitis.