What is a colonoscopy?

Colonoscopy enables your doctor to examine the lining of your colon (large intestine) for abnormalities by inserting a flexible tube as thick as your finger into your anus and slowly advancing it into the rectum and colon. If your doctor has recommended a colonoscopy, this brochure will give you a basic understanding of the procedure - how it's performed, how it can help, and what side effects you might experience. It can't answer all of your questions since much depends on the individual patient and the doctor. Please ask your doctor about anything you don't understand.

What preparation is required?

Your doctor will tell you what dietary restrictions to follow and what cleansing routine to use. In general, the preparation consists of either consuming a large volume of a special cleansing solution or clear liquids and special oral laxatives. The colon must be completely clean for the procedure to be accurate and complete, so be sure to follow your doctor's instructions carefully.

Can I take my current medications?

Most medications can be continued as usual, but some medications can interfere with the preparation or the examination. Inform your doctor about medications you're taking, particularly aspirin products, arthritis medications, anticoagulants (blood thinners), insulin or iron products. Also, be sure to mention allergies you have to medications.

Alert your doctor if you require antibiotics prior to dental procedures, because you might need antibiotics before a colonoscopy as well.

What happens during colonoscopy?

Colonoscopy is well-tolerated and rarely causes much pain. You might feel pressure, bloating or cramping during the procedure. Your doctor might give you a sedative to help you relax and better tolerate any discomfort.

You will lie on your side or back while your doctor slowly advances a colonoscope through your large intestine to examine the lining. Your doctor will examine the lining again as he or she slowly withdraws the colonoscope. The procedure itself usually takes 15 to 60 minutes, although you should plan on two to three hours for waiting, preparation and recovery.

In some cases, the doctor cannot pass the colonoscope through the entire colon to where it meets the small intestine. Although another examination might be needed, your doctor might decide that the limited examination is sufficient.

What if the colonoscopy shows something abnormal?

If your doctor thinks an area needs further evaluation, he or she might pass an instrument through the colonoscope to obtain a biopsy (a sample of the colon lining) to be analyzed. Biopsies are used to identify many conditions, and your doctor might order one even if he or she doesn't suspect cancer. If colonoscopy is being performed to identify sites of bleeding, your doctor might control the bleeding through the colonoscope by injecting medications or by coagulation (sealing off bleeding vessels with heat treatment). Your doctor might also find polyps during colonoscopy, and he or she will most likely remove them during the examination. These procedures don't usually cause any pain.

What are polyps and why are they removed?

Polyps are abnormal growths in the colon lining that are usually benign (noncancerous). They vary in size from a tiny dot to several inches. Your doctor can't always tell a benign polyp from a malignant (cancerous) polyp by its outer appearance, so he or she might send removed polyps for analysis. Because cancer begins in polyps, removing them is an important means of preventing colorectal cancer.

How are polyps removed?

Your doctor might destroy tiny polyps by fulguration (burning) or by removing them with wire loops called snares or with biopsy instruments. Your doctor might use a technique called "snare polypectomy" to remove larger polyps. That technique involves passing a wire loop through the colonoscope and removing the polyp from the intestinal wall using an electrical current. You should feel no pain during the polypectomy.

What happens after a colonoscopy?

Your physician will explain the results of the examination to you, although you'll probably have to wait for the results of any biopsies performed.

If you have been given sedatives during the procedure, someone must drive you home and stay with you. Even if you feel alert after the procedure, your judgment and reflexes could be impaired for the rest of the day. You might have some cramping or bloating because of the air introduced into the colon during the examination. This should disappear quickly when you pass gas.

You should be able to eat after the examination, but your doctor might restrict your diet and activities, especially after polypectomy.

What are the possible complications of colonoscopy?

Colonoscopy and polypectomy are generally safe when performed by doctors who have been specially trained and are experienced in these procedures.

One possible complication is a perforation, or tear, through the bowel wall that could require surgery. Bleeding might occur at the site of biopsy or polypectomy, but it's usually minor. Bleeding can stop on its own or be controlled through the colonoscope; it rarely requires follow-up treatment. Some patients might have a reaction to the sedatives or complications from heart or lung disease.

Although complications after colonoscopy are uncommon, it's important to recognize early signs of possible complications. Contact your doctor if you notice severe abdominal pain, fever and chills, or rectal bleeding of more than one-half cup. Note that bleeding can occur several days after the procedure.