Sigmoidoscopy and colonoscopy
Sigmoidoscopy involves examination of the inside of the sigmoid colon and rectum using an endoscope. For a sigmoidoscopy, your doctor will instruct you to take a phosphate enema about 2 hours before the test. (However, in certain centers, a colonoscopy preparation (see below) is given in case a polyp is found that makes a colonoscopy necessary.) You should have only a light breakfast (or lunch) in the hours before the test. Some doctors use suppositories such as bisacodyl instead of an enema.
Colonoscopy is an endoscopic procedure in which the entire colon and rectum is viewed. If an abnormality is seen, it can be examined or removed. For a colonoscopy, it is imperative that the whole bowel be clean. The preparation must be thorough.
There are several methods, and your doctor must give you detailed instructions. You should plan to spend the preparation time with a toilet available nearby. The laxatives may be unpleasant, and sometimes they cause nausea and cramps. Nevertheless, they are safe when taken with clear fluids – and necessary if the examination is to be optimal. Adequate fluid intake should be maintained throughout. The product’s package insert will contain helpful advice on how to take the laxative(s). Elderly persons should be accompanied by a relative or friend when undergoing these preparations.