Colonoscopy (and its short version Flexible Sigmoidoscopy) is an examination method to check the large bowel (colon) through a camera on the tip of a flexible tube passed upstream through the rectum (back passage).
It provides a look on the lining of the bowel and helps diagnose problems like inflammation, diverticular disease, ulcers, polyps and cancer.
It also gives the chance to take samples (biopsies) of the bowel lining to be tested under the microscope. Small and medium size polyps can be removed during the procedure.
To ensure a good look on the colon it has to be prepared with special agents (e.g Picoprep). Washing it thoroughly with fluids is very necessary for this purpose.
The flexible sigmoidoscopy uses the same fiber optic scope but it is inserted to a shorter distance mainly to check the left side of the colon. Only enemas are required for the bowel preparation.
Colonoscopy can be done under sedation or under general anesthesia while sigmoidoscopy is usually done under sedation only.
During colonoscopy, the doctor will attempt to check the whole colon down to its first part where the small bowel joins the colon. This is successful in around 90% of patients. Reports all over the world demonstrate incomplete colonoscopy in around 10% due to many factors e.g. excessive loops of bowel or narrowing in the bowel that prevents passage of the scope.
Colonoscopy is relatively a safe procedure but occasionally associated with complication like perforation or bleeding. The risk of such complication is around 0.2%, and increases in older age, when there is intra-abdominal scarring related to previous operation, when polyps are found and need to be removed or when multiple biopsies are needed to be taken.
Bleeding is usually minor and stops spontaneously, rarely significant to require blood transfusion. Perforation is suspected when the patient develops severe pain after the procedure. If that happens the patient should seek medical advice immediately.
The bowel preparation can interfere with the absorption of certain medication, please inform the doctor if you are on blood thinners or antibiotics.
Mr. Falah El-Haddawi