A colonoscopy is a procedure that is done to thoroughly examine the lining of the colon and rectum. It is a long flexible tube that is inserted via the anus and is advanced along the rectum and colon until it reaches the beginning of the colon.
Your doctor may recommend an examination if you have symptoms suggesting possible problems in the colon or rectum. Some symptoms include bleeding, change in your bowel habits, unexplained abdominal symptoms. It is also used to monitor patients with inflammatory bowel disease, and for follow-up of patients with history of colon cancer or polyp. It is also recommended to have a screening at the age of 50 years (younger if you have any family history of colorectal cancer).
For colonoscopy and all other forms of examination of the colon, it is important to clear the colon of stools.
Patients are asked to take very potent laxatives to clear the colon. In most cases, if the procedure is to be done
in the morning, you will be asked to take the laxatives and purge the night before. If the procedure is to be done
in the afternoon, you will be asked to clear the bowels in the morning of the examination.
You will be encouraged to drink as much fluid as possible while you are clearing the bowel. You are also discouraged to take high fibre food such as vegetables and fruits 1 day prior the examination.
For patients who are on aspirin or other blood thinning medications, your colorectal surgeon will advise you on when you should stop those medications. After taking the medication to clean your colon, expect to make multiple trips to the toilet. A lot of people have expressed that this is the worst part of the entire procedure.
Relax. The worst part is already over.
Most people are fearful of colonoscopy because they feel that it is a very invasive procedure and are concerned about pain. Most patients do not feel any pain or even remember about the procedure after the they wake up from sedation.
On the day of the procedure, go to the Endoscopy Centre about 30 mins to one hour ahead of your appointment time. This is to give yourself some time to go to the toilet one last time should you need to and not feel so rushed.
Your doctor will likely give you a sedative by injection though some patients may want to watch the procedure "live" and want to do the entire procedure awake. This is possible as the procedure makes most people feel bloated and have the urge to pass motion rather than actual pain.
After you are asleep, your doctor will insert the colonoscope via the anus and advance it up the rectum and along the colon. The scope goes up along the left side of the abdominal cavity until it reaches just below the ribcage. It then makes a turn and goes across to the right side, before finally going downwards to the right lower part to the abdomen. The end of the colon is recognized as such due to the presence of the appendix opening and the opening of the small intestines into the colon (the ileocaecal valve). In certain conditions where it is indicated, your doctor will advance the scope through the ileocaecal valve to inspect the last part of the ileum.
One of the main advantages of colonoscopy over other methods of colon examination is that it allows direct visualization rather than rely on indirect imaging techniques. It also allows any adherent stools to be washed away to see the colon lining beneath. It is also the only technique that allows to tissues to be removed for biopsies and for polyps to be removed.
Most people do not have any side effects after the procedure. Some people may feel bloated because of residual air left in the colon. Do remember that it is normal to have less bowel movement the next few days because a lot of stools have already been cleared out by the bowel preparation.