Mechanism of pancreatitis caused by ERCP

Background: Acute pancreatitis can develop after either ERCP or endoscopic sphincterotomy (ES). The pathogenesis of this complication remains poorly understood. Methods: The frequency and severity of acute pancreatitis were retrospectively evaluated after 17,602 ERCP procedures and 3003 ES procedures. Pancreatitis was diagnosed and evaluated according to the scoring system of Ranson and criteria developed in Japan. Results: Pancreatitis developed after 15 (0.09%) of 17,602 ERCP procedures and 13 (0.43%) of 3003 ES procedures (p = 0.0001, chi-square). The severity of pancreatitis (Ranson score) was less than 3 in 10 cases of ERCP-induced pancreatitis and from 3 to 5 In 5 cases. One (7%) of the 15 patients with ERCP-related pancreatitis died. All 13 patients with ES-Induced pancreatitis had a Ranson score of less than 3; none died (p = 0.04, Fisher exact test). The ERCP pancreatitis score (Japanese criteria) beyond 48 hours after the onset of pancreatitis increased in 5 (33%) of the 15 patients with ERCP-induced pancreatitis; the score did not increase in any of the 13 patients with ES-induced pancreatitis (p = 0.04, Fisher exact test). Conclusions: Although the frequency of ES-induced pancreatitis is significantly higher than that of post-ERCP pancreatitis, the frequency of severe pancreatitis within 48 hours and worsening of pancreatitis after 48 hours is significantly lower with ES-Induced pancreatitis. Our hypothesis is that the lowering of pancreatic intraductal pressure after ES mitigates the severity of postprocedure pancreatitis.