Colonic dysmotility and morphological abnormality frequently detected in Japanese patients with irritable bowel syndrome

BACKGROUND/AIMS Colonoscopy and computed tomography (CT) are used primarily to exclude organic diseases in patients with irritable bowel syndrome (IBS), rather than to assess the pathophysiology of IBS. We aimed to evaluate colonic dysmotility and morphology in Japanese patients with IBS. METHODS One hundred eighty-four patients with IBS and 49 asymptomatic controls who underwent colonoscopy in combination with CT colonography or barium enema were retrospectively reviewed between 2008 and 2012. Water-aided colonoscopy was performed without sedation by a single endoscopist. The duration and pattern of colonic movement and cecal intubation time were recorded. To assess colonic morphology, barium enema or CT colonography were performed immediately after colonoscopy. RESULTS Colonic dysmotility was more frequent in the IBS group (28.8% vs. 2.0% in controls, P<0.001), especially in cases of IBS with diarrhea (IBS-D) (IBS with constipation [IBS-C] 28.8% vs. IBS-D 60.0% vs. mixed IBS [IBS-M] 5.1%, P<0.001). Colonic morphological abnormality was more frequent in the IBS group than in the control group (77.7% vs. 24.5%, P<0.001), especially in IBS-M and IBS-C groups (IBS-C 77.5% vs. IBS-D 48.9% vs. IBS-M 100%, P<0.001). Most patients with IBS with colonic dysmotility had experienced stress related to their symptoms. Cecal intubation time was significantly longer in the IBS group than in the control group (12.1±6.9 minutes vs. 4.6±1.9 minutes, P<0.001). CONCLUSIONS Unsedated colonoscopy, combined with radiographic findings, can detect colonic dysmotility and morphological abnormality. Technical difficulties observed during cecal intubation may partially explain the pathophysiology of IBS.