Prospective evaluation of yield of endoscopic ultrasonography in the etiological diagnosis of "idiopathic" acute pancreatitis

Background: Etiology of acute pancreatitis (AP) remains idiopathic in 30% of patients. Endoscopic ultrasound (EUS) has been shown to increase the diagnostic yield in patients with idiopathic AP (IAP). Aim: The aim of this study was to evaluate the role of EUS in achieving etiological diagnosis in patients with IAP. Materials and Methods: Consecutive 192 patients with IAP were evaluated prospectively with EUS over a period of 2 years. Patients who had no etiological diagnosis for AP after detailed history, clinical examination, laboratory investigations, and magnetic resonance cholangiopancreatography were included in the study. Results: The mean age of patients was 34.6 ± 12 and male:female ratio was 2.1:1. Of these, 135 patients had gallbladder intact (Group A) and 57 patients had undergone cholecystectomy (Group B). In Group A, EUS identified a possible cause in 79 (58.5%) patients; microlithiasis (n = 48), chronic pancreatitis (CP) (n = 23), common bile duct (CBD) and gallbladder stone (n = 3), pancreatic divisum (n = 3), small pancreatic tumor (n = 1), and anomalous pancreaticobiliary junction (n = 1). In Group B, EUS yielded diagnosis in 28 (49.1%) patients; CP (n = 22), ascariasis (n = 3), CBD stone (n = 2), and pancreatic divisum (n = 1). Overall EUS helped in achieving etiological diagnosis in 107 (55.1%) of patients with IAP. The presence of intact gallbladder showed a tendency for increased diagnostic yield (P = 0.06). Conclusion: EUS is a useful modality to establish the diagnosis in IAP and this technique should be incorporated in the evaluation of IAP