When presented with a new case of chronic gut pain, a gastroenterologist will often order a colonoscopy exam. The purpose of this is to examine the full length of the interior of the colon from the anus to the cecum. This makes use of a flexible camera tube which is inserted via the anus and can be manipulated to provide images as it precedes within the interior of the gut. The gastroenterologist will look for physical problems. These might include anal fissures, hemorrhoids, colon cancer, polyps, diverticula, ulcerative colitis, inflammation, or any form of narrowing or structural abnormality.
An alternative to a colonoscopy is a sigmoidoscopy which is used to inspect only the final section of the colon and does not travel all the way up to the cecum.
The first step of a colonoscopy is to do the bowel preparation. Typically this will involve refraining from eating for up to 12 hours before the procedure and drinking a large volume of osmotic laxative solution, which normally contains polyethylene glycol. This will cause many bowel movements and will eventually completely clean out the gut. This is important because it will allow the gastroenterologist to inspect the wall of the colon without any obstruction by fecal matter.
A colonoscopy is normally done under a fairly heavy sedation. After changing into hospital robes the patient will lie on a bed and the medical staff will inject sedatives. These will cause the patient to fully relax and not really to remember anything that was done. The colonoscopy endoscope contains a camera and also various attachments that allow the doctor to take samples or do minor surgery on regions in the colon. This includes the removal of significant polyps that might eventually become cancerous. The endoscope is inserted until the end of the instrument finishes up in the cecum, where the ileocecal valve and orifice of the appendix can be examined.
Recovery is straightforward and the patient can eat or drink shortly after the procedure. If tissue samples have been taken or surgery has been performed then some minor bleeding might be experienced.