Colonoscopy is a procedure that enables your physician to examine the lining of the colon (larger bowel) for abnormalities by inserting a flexible tube that is about the thickness of your finger into the anus and advancing it slowly into the rectum and colon.

The colon must be completely clean for the procedure to be accurate and complete. Your physician will give you detailed instructions regarding the dietary restrictions to be followed and the cleansing routine to be used. In general, preparation consists of either consumption of a large volume of a special cleansing solution or several days of clear liquids, laxatives, and enemas prior to the examination. Follow your doctor's instructions carefully. If you do not, the procedure may have to be canceled and repeated later.

Most medications may be continued as usual, but some medications can interfere with the preparation or the examination. It is therefore best to inform your physician of your current medications as well as any allergies to medications several days prior to the examination. Aspirin products, arthritis medications, anticoagulants (blood thinners), insulin, and iron products are examples of medications whose use should be discussed with your physician prior to the examination. You should alert your doctor if you require antibiotics prior to undergoing dental procedures, since you may need antibiotics prior to colonoscopy as well.

Colonoscopy is usually well tolerated and rarely causes much pain. There is often a feeling of pressure, bloating, or cramping at times during the procedure. Your doctor may give you medication through a vein to help you relax and better tolerate any discomfort from the procedure. You will be lying on your side or on your back while the colonoscope is advanced slowly through the large intestine. As the colonoscope is slowly withdrawn, the lining is again carefully examined. The procedure usually takes 15 to 60 minutes. In some cases, passage of the colonoscope through the entire colon to its junction with the small intestine cannot be achieved. The physician will decide if the limited examination is sufficient or if other examinations are necessary.

If your doctor thinks an area of the bowel needs to be evaluated in greater detail, a forceps instrument is passed through the colonoscope to obtain a biopsy (a sample of the colon lining). This specimen is submitted to the pathology laboratory for analysis. If colonoscopy is being performed to identify sites of bleeding, the areas of bleeding may be controlled through the colonoscope by injecting certain medications or be coagulation (sealing off bleeding vessels with heat treatment). If polyps are found, they are generally removed. None of these additional procedures typically produce pain. Remember, the biopsies are taken for many reasons and do not necessarily mean that cancer is suspected.

Polyps are abnormal growths from the lining of the colon which vary in size from a tiny dot to several inches. The majority of polyps are benign (noncancerous) but the doctor cannot always tell a benign from a malignant (cancerous) polyp by its outer appearance alone. For this reason, removed polyps are sent for tissue analysis. Removal of colon polyps is an important means of preventing colorectal cancer.

Tiny polyps may be totally destroyed by fulguration (burning), but larger polyps are removed by a technique called snare polypectomy. The doctor passes a wire loop (snare) through the colonoscope and severs the attachment of the polyp from the intestinal wall by means of an electrical current. You should feel no pain during the polypectomy. There is a small risk that removing a polyp will cause bleeding or result in a burn to the wall of the colon, which could require emergency surgery.

After colonoscopy, your physician will explain the results to you. If you have been given medications during the procedure, someone must accompany you home from the procedure because of the sedation used during the examination. Even if you feel alert after the procedure, your judgment and reflexes may be impaired by the sedation for the rest of the day, making it unsafe for you to drive or operate any machinery. You may have some cramping or bloating because of the air introduced into the colon during the examination. This should disappear quickly with passage of flatus (gas). Generally, you should able to eat after leaving the endoscopy, but your doctor may restrict your diet and activities after polypectomy.

Colonoscopy and polypectomy are generally safe when performed by physicians who have been specially trained and are experienced in these endoscopic procedures. One possible complication is a perforation or tear through the wall that could require surgery. Bleeding may occur from the site of biopsy or polypectomy. It is usually minor and stops on its own or can be controlled through the colonoscope. Rarely, blood transfusions or surgery may be required. Other potential risks include a reaction to the sedative used and complications from heart or lung disease. Localized irritation of the vein where medications were injected may rarely cause a tender lump for several weeks, but this will go away eventually. Applying hot packs or hot moist towels may help relieve discomfort. Although complications after colonoscopy are uncommon, it is important for you to recognize early signs of any possible complication. Contact your physician who performed the colonoscopy if you notice any of the following symptoms: severe abdominal pain, fever and chills, or rectal bleeding of more than one-half cup. Bleeding can occur several days after polypectomy.

Because education is an important part of comprehensive medical care, you have been provided with this information to prepare you for this procedure. If you have questions about your need for colonoscopy, alternative tests, the cost of the procedure, methods of billing, or insurance coverage, do not hesitate to speak to your doctor or your doctor's office staff. Most endoscopists are highly trained specialists and welcome your questions regarding their credentials and training. If you have questions that have not been answered, please discuss them with the endoscopy nurse or your physician before the examination begins.