Gastrointestinal: Complications of colonoscopy

Abstract

Colonoscopy is being increasingly used for a variety of indications, including surveillance for bowel cancer. However, in assessing the net benefit of colonoscopy, one negative issue is that of complications from the procedure. The major serious complication is that of colonic perforation. This varies in frequency from 1:500 to 1:5000 and is more frequent with therapeutic procedures, particularly colonic dilatation. Other higher-risk settings include difficult colonoscopies because of colonic strictures, dense pelvic adhesions, severe diverticulosis and the potential for incarceration of the colonoscope in an inguinal or other hernia. Other complications include colonic bleeding (largely after polypectomy), splenic injury, colonic volvulus and a post-polypectomy syndrome that might be related to microperforation. There can also be complications from the bowel preparation, particularly in patients who are elderly and unwell and others with renal impairment. Two complications from colonoscopy are illustrated below. Figure 1 is a chest radiograph that shows both free intra-abdominal gas and subcutaneous emphysema. The patient was a middle-aged woman who had colonoscopy for severe Crohn’s disease. During the procedure, she developed periorbital edema and facial swelling. The site of the retroperitoneal perforation was not identified at the time of colonoscopy but seemed likely to be in the sigmoid colon. She was treated with intravenous antibiotics but did not require surgery. Figure 2 shows a plain abdominal radiograph that was taken during colonoscopy when an elderly patient developed abdominal pain with a bulging and tender left-sided inguinal hernia. The colonoscope could neither be advanced nor removed. A surgical consultation was obtained and the hernia was manually reduced by the surgeon after the patient was deeply sedated. Incarceration of colonoscopes in hernias can sometimes be overcome by moving to the hernia sac and slowly withdrawing the colonoscope through the region.