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Diagnostic Tests
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Colonoscopy (koh-luh-NAH-skuh-pee) lets the physician look inside your entire large intestine, from the lowest part, the rectum, all the way up through the
colon to the lower end of the small intestine. The procedure is used to diagnose the causes of unexplained changes in bowel
habits. It is also used to look for early signs of cancer in the colon and rectum. Colonoscopy enables the physician to see
inflamed tissue, abnormal growths, ulcers, bleeding, and muscle spasms.
For the procedure, you will lie on your left side on the examining table. You will probably be given pain medication and a
mild sedative to keep you comfortable and to help you relax during the exam. The physician will insert a long, flexible, lighted
tube into your rectum and slowly guide it into your colon. The tube is called a colonoscope (koh-LON-oh-skope). The scope
transmits an image of the inside of the colon, so the physician can carefully examine the lining of the colon. The scope bends,
so the physician can move it around the curves of your colon. You may be asked to change position occasionally to help the
physician move the scope. The scope also blows air into your colon, which inflates the colon and helps the physician see better.
If anything unusual is in your colon, like a polyp or inflamed tissue, the physician can remove a piece of it using tiny instruments
passed through the scope. That tissue (biopsy) is then sent to a lab for testing. If there is bleeding in the colon, the physician
can pass a laser, heater probe, or electrical probe, or inject special medicines, through the scope and use it to stop the
bleeding.
Bleeding and puncture of the colon are possible complications of colonoscopy. However, such complications are uncommon.
Colonoscopy takes 30 to 60 minutes. The sedative and pain medicine should keep you from feeling much discomfort during the
exam. You will need to remain at the physician's office for 1 to 2 hours until the sedative wears off.
Preparation
Your colon must be completely empty for the colonoscopy to be thorough and safe. To prepare for the procedure you may have
to follow a liquid diet for 1 to 3 days beforehand. A liquid diet means fat-free bouillon or broth, Jell-O®, strained fruit
juice, water, plain coffee, plain tea, or diet soda. You may need to take laxatives or an enema before the procedure. Also,
you must arrange for someone to take you home afterward--you will not be allowed to drive because of the sedatives. Your physician
may give you other special instructions.
The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive
and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health under the U.S. Department of Health and
Human Services. Established in 1980, the clearinghouse provides information about digestive diseases to people with digestive
disorders and to their families, health care professionals, and the public. NDDIC answers inquiries; develops, reviews, and
distributes publications; and works closely with professional and patient organizations and Government agencies to coordinate
resources about digestive diseases.
Publications produced by the clearinghouse are reviewed carefully for scientific accuracy, content, and readability.
This e-text is not copyrighted. The clearinghouse encourages users of this e-pub to duplicate and distribute as many copies
as desired.
e-text posted: 7 July 1998
