Colonoscopy Explained

• Individuals wishing to have colorectal cancer screening
• Individuals with rectal bleeding, iron deficiency anemia, a change of bowel function, or abdominal pain
• Individuals with a family history of colon or rectal cancer or colon polyps
• Individuals with a history of ulcerative colitis or Crohn's disease

Colonoscopy is a procedure that enables your physician to examine the lining of the colon (large 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 special cleansing solution or laxative, and/or one or two days of clear liquids.  Occasionally enemas are given prior to the examination. Follow your doctor's instructions carefully. If you do not, the procedure may have to be cancelled and repeated later.  If you have problems while taking any preparation, contact the doctor or nurse on call.

Most medications may be continued as usual, but some medications can interfere with the preparation or the examination. Inform your physician of your current medications as well as any allergies to medications (preferably bring a list) 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. It is also essential that you alert your doctor if you require antibiotics prior to undergoing dental procedures, since you may need antibiotics prior to colonoscopy as well.

The physician will review the procedure with you and ask you to sign a standard consent form.  This authorizes your doctor to perform the test.  Please read this and be sure you understand it to your satisfaction.  Be sure you have all your questions and concerns answered by the doctor before signing it.

Colonoscopy is usually performed on an outpatient basis.  It 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 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 small sample of the colon lining) or a small brush is introduced to collect cells (a cytology test). These specimens are 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 by coagulating the bleeding vessels. If polyps are found, they are generally removed. None of these additional procedures produce pain since the colon lining can only sense stretching. Remember, 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 by the pathologist. 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; however, if a biopsy has been taken, final results will not be available for a day or so. If you have been given medications during the procedure, you will be observed until most of the effects of the sedation have worn off (for 1/2 to 2 hours). Due to the sedation, it is essential that you have someone available to drive you home or the doctor will be unable to do the procedure.  You should not drive or operate dangerous machinery within 24 hours of your procedure.  We recommend you take the remainder of the day off of work. You may have some cramping or bloating because of the air introduced into the colon during the examination. This should disappear quickly with the passage of flatus (gas). Generally, you should be able to eat after leaving the endoscopy area but your doctor may restrict your diet and activities, especially after polypectomy.

Colonoscopy and polypectomy are generally safe when performed by physicians who have been specially trained and are experienced in these endoscopic procedures.  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. One possible complication is a perforation or tear through the bowel wall which 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 sedatives used and complications from heart or lung disease. Localized irritation of the vein where medications were injected may cause a tender lump lasting for several weeks, but this will go away eventually. Applying hot packs or hot moist towels may help relieve discomfort. 

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. If you have questions that have not been answered, please discuss them with your endoscopy nurse or physician.