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What you need to know about colonoscopy

A 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.

What preparation is needed?

The colon must be completely clean for the procedure to be accurate and complete. Your doctor 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.

What about my medications?

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. These include:

  • Aspirin products
  • Arthritis medications
  • Anticoagulants (blood thinners)
  • Insulin
  • Iron products

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.

What can be expected during a colonoscopy?

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 As the colonoscope is slowly withdrawn, the lining is again carefully examined.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 15-60 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.

What if the colonoscopy shows something abnormal?

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) or a small brush is introduced to collect these cells. These specimens are submitted to a 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 produce pain since the colon lining can sense stretching. Remember biopsies are taken for many reasons and do not necessarily mean that cancer is suspected.

What are polyps and why are they removed?

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 (non-cancerous) 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 to a pathologist for tissue analysis. Removal of colon polyps is an important means of preventing colorectal cancer.

How are polyps removed?

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.

What happens after colonoscopy?

After colonoscopy, your physician will explain the results to you. If you have been given medications during the procedure, you will be observed until most of the effects of sedation have worn off (for 1/2 to 2 hours). You will need someone to drive you home after the procedure.

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 be able to eat after leaving the endoscopy area but your doctor may restrict your diet and activities, especially after polypectomy.

What are possible complications of colonoscopy?

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.

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

To the patient

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.