What is colonoscopy?

​Colonoscopy is an examination of the large intestine using a flexible tube (colonoscope) with a video camera at the end. The tube is inserted into the rectum and advanced through the colon. At the time of the examination the doctor examines the lining of the intestine and can take tissue samples (biopsies) or remove abnormal growths such as polyps. Other procedures are sometimes performed such as applying clips or electrocautery to prevent or control bleeding, or injecting fluid or dyes into the bowel wall. Most patients lie on the left side and usually receive a sedative medication injected through an intravenous line (IV) and are sleepy or asleep throughout the procedure. On average, the procedure takes between 20 minutes and an hour.

What is the success rate of colonoscopy?

An examination of the entire colon is possible in the overwhelming majority of patients. Occasionally a complete examination is not possible because of narrowing of the colon, the presence of an unusually long and twisty colon, or looping and sharp angulation (usually from scarring related to previous surgery or diverticulitis). Even when the entire colon can be reached with the colonoscope, there is a chance that a polyp or other abnormality will not be seen. This chance is higher when pre-colonoscopy cleansing of the colon is not adequate, but still exists even when the colon is well prepared.

​

​If the examination is incomplete because the entire colon could not be seen, or the preparation was inadequate, you may need additional testing or perhaps another colonoscopy.

What can I expect after the procedure?

You may feel bloated or have cramping for 1-2 hours after the procedure is completed. You may feel tired and need to take a nap once you are back home. It is common to go for a day or two without a bowel movement. If biopsies are done or a polyp is removed, you may see a small amount of bleeding from the rectum. You should plan to eat a light meal after the procedure, and then return to a normal diet if you are feeling fine. You should be completely recovered and able to return to your usual activities by the next day.
 

You cannot drive for a minimum of 12 hours after your sedated procedure.

Why is colonoscopy done?

Colonoscopy is done to detect colon cancer or pre-cancerous polyps in both average risk individuals and in those with an increased risk of colon cancer, such as those with a family history of colon cancer or a personal history of inflammatory bowel disease. It is also done as part of the evaluation of symptoms such as rectal bleeding, diarrhea, change in bowel habits, and other conditions. 

Colon cancer is the second leading cause of cancer deaths in the United States. The great majority of colon cancers can be prevented or detected early when colonoscopy is performed appropriately.  Most average risk individuals should begin screening for colon cancer at age 50 with a colonoscopy.  Any polyps detected during the colonoscopy exam are removed, thus preventing formation of the cancer before it begins.

Some persons may require colonoscopy at an earlier age based on their family history or heritage. Colonoscopy has been shown to reduce the occurrence of colon cancer in the United States.

What are the risks of colonoscopy and associated procedures?

Colonoscopy is considered a relatively safe procedure, but serious complications occur in about 1 person out of 1000 (0.1%). These complications include infection, perforation (puncture or tear of the bowel wall creating a hole), bleeding (frequently from a treatment site, such as the place where a polyp was removed), cardiac problems such as heart attack or rhythm disturbances, sedation related complications such as aspiration or decreased respiration, and even death which is quite rare.