What is a colonoscopy? A colonoscope is a long flexible tube that is about the thickness of a finger. It is inserted through the rectum into the large intestine (colon) and allows the physician to carefully examine the lining of the colon. Abnormalities suspected by xray can be confirmed and studied in detail. Abnormalities which are too small to be seen on x-ray may also be identified.
If the doctor sees a suspicious area or needs to evaluate an area of inflammation in greater detail, he can pass an instrument through the colonoscope and take a small piece of tissue (a biopsy) for examination in the laboratory. Biopsies are taken for many reasons and do not necessarily mean that cancer is suspected. A small brush can be introduced as well to collect cells from an abnormal area for examination in the laboratory (a form of pap test or “cytology”).
Why is a colonoscopy necessary? Colonoscopy is a valuable tool for the diagnosis and treatment of many diseases of the large intestine. Abnormalities suspected by x-ray can be confirmed and studied in detail. Even when x-rays are negative, the cause of symptoms such as rectal bleeding or change in bowel habits may be found by colonoscopy. It is useful for the diagnosis and follow-up of patients with inflammatory bowel diseases as well.
Colonoscopy’s greatest impact is probably in its contribution to the control of colon cancer by polyp removal. Before colonoscopy became available, major abdominal surgery was the only way to remove colon polyps to determine if they were benign or malignant. Now, most polyps can be removed easily and safely without surgery. Periodic colonoscopy is a valuable tool for follow-up of patients with previous polyps, colon cancer, or a family history of colon cancer.
A Colonoscopy is a safe and extremely worthwhile procedure which is very well tolerated. The decision to perform this procedure was based upon assessment of your particular problem. If you have any questions about your need for colonoscopy, do not hesitate to speak to the doctor.
What preparation is required? For the best possible examination, the colon must be completely empty of waste material. Only clear liquids should be taken for one or two days before the procedure. Discontinue the use of aspirin products and iron tablets for one week before the examination. Laxatives or enemas are taken before the colonoscopy. The doctor will give you detailed instructions in the cleansing routine that he prefers and can advise you on the specific liquids that are allowed.
Be sure to let the doctor know if you are allergic to any drugs. A companion must accompany you to the colonoscopy because you will be given medication to help you relax. It will make you drowsy, so you will need someone to take you home. You will not be allowed to drive after the procedure. Even though you may not feel tired, your judgment and reflexes may not be normal.
What should you expect during the procedure? The doctor will give you medication through a vein to make you relaxed and sleepy.
While you are lying in a comfortable position, the colonoscope is inserted into the rectum and gradually advanced through the colon while the lining is examined thoroughly. The colonoscope is then slowly withdrawn while the intestine is again carefully examined.
The procedure is usually well tolerated and rarely causes pain. There may be some discomfort during the colonoscopy but it is usually mild. In rare cases, passage of the colonoscope through the entire colon cannot be achieved. A limited examination may be sufficient if the area of suspected abnormality was well visualized.
What is a polypectomy? During the course of the examination, a polyp may be found. Polyps are abnormal growths of tissue which vary in size from a tiny dot to several inches. If the doctor feels that removal of the polyp is indicated, he will pass a wire loop or snare through the colonoscope and sever the attachment of the polyp from the intestinal wall by means of an electrical current. If additional polyps are detected, they may be removed as well. You should feel no pain during removal of the polyp. Polyps are usually removed because they can cause rectal bleeding or contain cancer. Although the majority of polyps are benign (noncancerous), a small percentage may contain an area of cancer in them or may develop into cancer. Removal of colon polyps, therefore, is an important means of prevention and cure of colon cancer, which is a leading form of cancer in the United States.
Are there any complications from colonoscopy and polypectomy? Colonoscopy and polypectomy are safe and are associated with very low risk when performed by a gastroenterologist who has been specially trained and is experienced in these endoscopic procedures. One possible but rare complication is perforation in which a tear through the wall of the bowel may allow leakage of intestinal fluids.
Bleeding may occur from the site of a biopsy or polyp removal. It is usually minor and stops on its own or can be controlled by cauterization (application of electrical current) through the colonoscope. Rarely, transfusions or surgery may be required.
Localized irritation of the vein may occur at the site of medication injection. A tender lump develops which may remain for several days.
What happens after the colonoscopy? You will be kept in the endoscopic area until most of the effects of the medication have worn off. You may feel bloated for a few minutes right after the procedure because of the air that was introduced while examining the colon.
You will be able to resume your diet after the colonoscopy unless you are instructed otherwise. If a polyp has been removed, the doctor may wish your diet to be limited before returning to your regular diet. If the polyp is an unusually large one, you may be admitted to the hospital for observation.