Colonoscopy Health Article

Definition

A colonoscopy is an internal examination of the colon (large intestine) and rectum, using an instrument called a colonoscope.

How the test is performed

The colonoscope has a small camera attached to a flexible tube. Unlike sigmoidoscopy, which can only reach the lower third of the colon, colonoscopy examines the entire length of the colon.

You will lie on your left side with your knees drawn up toward the chest. After you have received a sedative and pain reliever, the colonoscope is inserted through the anus and gently advanced to the lowest part of the small bowel.

Air will be inserted through the scope to provide a better view. Suction may be used to remove fluid or stool.

Because the health care provider gets a better view as the colonoscope is pulled back out, a more careful examination is done while the scope is being pulled out. Tissue samples may be taken with tiny biopsy forceps inserted through the scope. Polyps may be removed with electrocautery snares, and photographs may be taken.

Specialized procedures, such as laser therapy, may also be done.

How to prepare for the test

You will need to completely cleanse the bowel. Your health care provider will give you instructions for doing this. This may include a combination of enemas, not eating solid foods for 2 or 3 days before the test, and taking laxatives. You will usually be told to stop taking aspirin, ibuprofen, naproxen, or other blood-thinning medications for several days before the test.

You will be asked to drink plenty of clear liquids for 1 - 3 days before the test. Examples of clear liquids are: fat-free bouillon or broth, water, clean coffee or tea, strained fruit juices, sports drinks, and gelatin.

Unless otherwise instructed, continue taking any regularly prescribed medication. Stop taking iron preparations a few weeks before the test, unless otherwise instructed by your health care provider. Iron residues produce a dark black stool, which makes the view inside the bowel less clear.

People with some heart valve diseases may receive antibiotics before and after the test to prevent infection. Outpatients must plan to have someone take them home after the test, because they will be woozy and unable to drive.

Infants and children:

The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For general information regarding how you can prepare your child, see the following topics:

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• School age test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)