Usefulness of endoscopic ultrasonography in patients with “idiopathic” acute pancreatitis

PURPOSE: No underlying cause is found in as many as 30% of patients with acute pancreatitis. The aim of this study was to evaluate the usefulness of endoscopic ultrasonography in the diagnosis of biliary tract pathology or chronic pancreatitis in these patients. SUBJECTS AND METHODS: We evaluated 168 patients who were referred with idiopathic pancreatitis. Diagnoses obtained by endoscopic ultrasonography were prospectively compared with those obtained at surgery in 101 patients, by endoscopic cholangiopancreatography in 49 patients, or by bile crystal analysis and medical follow-up in 18 patients. RESULTS: Endoscopic ultrasonography was abnormal in 135 (80%) patients, 124 of whom had biliary tract disease. When the results of endoscopic ultrasonography were compared with those made after multidisciplinary investigations, endoscopic ultrasonography correctly identified the cause—most commonly biliary tract disease—of the “idiopathic” pancreatitis in 155 (92%) of the 168 patients. CONCLUSIONS: Endoscopic ultrasonography is valuable in determining the cause of acute pancreatitis in patients initially considered to have idiopathic pancreatitis.