An extended retroperitoneal emphysema with diversion colitis after colonoscopy

A 68-year-old man with a history of intersphincteric resection and transverse colostomy for rectal cancer underwent diagnostic colonoscopy as a post-operative follow up. Colonoscopy revealed diversion colitis of the sigmoid colon. Two hours after the examination, the patient complained of mild abdominal pain. Blumberg sign was negative and no remarkable changes were observed, but abdominal pain did not improve for 6 hours. A CT scan showed retropneumoperitoneum, pneumomediastinum, subcutaneous emphysema and pneumatosis intestinalis of the sigmoid colon without any evidence of perforation. We diagnosed retroperitoneal emphysema with diversion colitis after colonoscopy and the patient was admitted to our hospital. We decided on a conservative treatment method because of the lack of peritonitis and good general condition. The clinical course was uneventful and he was discharged 11 days after the initial observation. Retroperitoneal emphysema is a very rare complication that occurs after colonoscopy. We report our case with a literature review of 25 cases of retroperitoneal emphysema after colonoscopy in Japan.