Role of endoscopic ultrasound in idiopathic acute pancreatitis with negative ultrasound, computed tomography, and magnetic resonance cholangiopancreatography

BACKGROUND: Idiopathic acute pancreatitis (IAP) is a diagnostic challenge. Finding a treatable cause after appropriate investigation may help to prevent recurrent pancreatitis and further management. The aim of our study was to retrospectively report our experience with endoscopic ultrasound (EUS) in investigating patients with IAP. METHODS: Forty patients (26 males; age range: 17-72 years) of IAP with no underlying cause identified on transabdominal ultrasound, computed tomography and magnetic resonance cholangiopancreatography were studied. In 23 patients (57.5%), it was the first attack of acute pancreatitis whereas in 17 patients (42.5%) there was at least one previous attack of documented acute pancreatitis. EUS examination was done using a radial echoendoscope. RESULTS: Twenty (50%) of the patients had biliary tract disease (cholelithiasis in 3, gallbladder sludge in 13, choledocholithiasis in 1 and common bile duct sludge in 3 patients). One each had an 8 mm tumor in the head of pancreas and pancreas divisum. No underlying cause could be found in 18 (45%) patients. Nine patients had features of chronic pancreatitis (CP) and the remaining had a normal pancreas. CONCLUSIONS: Occult biliary pathology is the predominant cause of IAP. Half of the cases without identified etiology already had an underlying CP. EUS is a very important tool in evaluating IAP especially after an initial negative diagnostic workup.