Colonoscopy Health Article

Definition

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

How the test is performed

The colonoscope is a small camera attached to a flexible tube. Unlike sigmoidoscopy, which examines only 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've 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 secretions.

Since better views are obtained as the colonoscope is pulled back out, a more careful examination is done during withdrawal of the scope. 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

Thorough cleansing of the bowel is mandatory. Instructions for doing this will be given by the provider. This will include using enemas, not eating solid foods 2 or 3 days before the test, and taking laxatives. You may be told to stop taking aspirin or other blood-thinning medications for several days before the test.

To avoid dehydration, drink plenty of clear liquids such as juices and broths. Unless otherwise instructed, continue taking any regularly prescribed medication. Stop taking iron preparations a few weeks before the test, unless otherwise instructed by the health care provider. Iron residues produce a dark black stool, which makes the view inside the bowel less clear.

People with heart valve disease may receive antibiotics before and after the test to prevent infection. Outpatients must plan to have someone take them home after the test, as 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)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)