Your Health - Colonoscopy

Colonoscopy

View an animated version of this procedure:

Definition

A colonoscopy is a visual exam of the lining of the large intestine, also called the bowel or colon, with a colonoscope. A colonoscope is a flexible tube with a light and a viewing device. It allows the doctor to view the inside of the colon through a tiny video camera.

Colonoscopy Procedure

Parts of the Body Involved

The large intestine (colon) and rectum are involved in a colonoscopy.

Reasons for Procedure

Colonoscopy is performed to visualize, diagnose, and sometimes treat problems inside the large intestine. The procedure is most often recommended for the following reasons:

To locate the source of lower intestinal bleeding
To diagnose changes in bowel habits
To determine the cause of lower abdominal pain
To detect early signs of colon cancers or pre-cancers (polyps) in individuals without symptoms but who are at increased risk for these conditions
To obtain tissue samples for testing
To remove a polyp (an abnormal growth on the inside lining of the intestine)
To stop intestinal bleeding

Risk Factors for Complications During the Procedure

Active colitis, diverticulitis, or other acute bowel disease
Previous treatment with radiation therapy
Treatment with certain medications, including aspirin and other drugs with blood-thinning properties

What to Expect

Prior to Procedure

Your doctor will likely do the following:

Physical exam
Health history
Review of medications
Test to check your stool for hidden blood, called "occult blood"

In the days leading up to your procedure:

Your colon must be completely cleaned out before the procedure. Any stool left in the colon will block the doctor's view and limit the procedure's success. A number of cleansing methods may be used, including enemas, laxatives, and a clear-liquid diet. You may be asked to drink a large container of solution that aids in the complete emptying of the colon. This preparation may start several days before the procedure. It is important that you complete this preparation step.
Do not take bulk-forming laxatives or iron-containing medications or supplements for one week before the procedure, unless told otherwise by your doctor.
Do not take aspirin or other anti-inflammatory or blood-thinning drugs for one week before the procedure, unless told otherwise by your doctor.
Do not eat or drink anything for 8 to 10 hours before the procedure.
If you have insulin-dependent diabetes, ask your doctor about any adjustments to your insulin dose.
Arrange for a ride to and from the procedure.

During Procedure

You will be given a sedative.

Anesthesia

Medication is given to sedate you and to decrease discomfort.

Description of the Procedure

You lie on your left side with knees bent and drawn up toward your chest. The gastroenterologist or endoscopist (who may be a surgeon) slowly inserts the lubricated, pencil-sized colonoscope through the rectum and into the bowel. The colonoscope injects air into the colon, and a small attached video camera lets the doctor view the colon's lining on a video screen. The doctor will continue guiding the instrument through the bowel and assess the lining, while looking for abnormalities.

A tissue sample or polyps may be removed and analyzed. A biopsy is always necessary to diagnose cancer or pre-cancer. If tissue is removed, a small amount of bleeding may occur during the first 2 days after the procedure.

After Procedure

A laboratory will exam any tissue or fluid that was removed.

How Long Will It Take?

The colonoscopy takes less than one hour. Expect to stay at the hospital or doctor's office for another hour or two or until the sedative wears off. Because of the medication used, it is generally required that someone drive you home from the procedure.

Will It Hurt?

Although most patients report little or no discomfort during the procedure, there may be feelings of cramping, bloating, fullness, or a need to have a bowel movement.

Possible Complications

Bleeding
Perforation or puncture of the bowel

Average Hospital Stay

There is no hospital stay associated with a colonoscopy procedure.

Postoperative Care

Because the sedative will make you drowsy, don't drive, operate machinery, or make important decisions the day of the procedure.
Rest for the remainder of the day.
Feelings of bloating, gas, or cramping may persist for 24 hours.
Resume medications as instructed by your doctor.
Resume your normal diet, unless told otherwise by your doctor.

Outcome

The doctor will usually give you a preliminary report after the medication wears off and you are more alert. The results from a biopsy can take as long as 1 to 2 weeks to be completed. Schedule a follow-up appointment with your doctor.

Call Your Doctor If Any of the Following Occurs

Signs of infection, including fever and chills
Bleeding; notify the doctor if you pass a teaspoon or more of blood
Black, tarry stools
Severe abdominal pain
Coughing, shortness of breath, chest pain, severe nausea or vomiting

RESOURCES:

American Society for Gastrointestinal Endoscopy
http://www.askasge.org

National Digestive Diseases Information Clearinghouse, NIH
http://digestive.niddk.nih.gov

CANADIAN RESOURCES:

Public Health Agency of Canada
http://www.phac-aspc.gc.ca/new_e.html

Radiology for Patients
http://www.radiologyinfo.ca

References:

American Gastroenterological Association website. Available at: http://www.gastro.org/. Accessed October 14, 2005.

Medical encyclopedia: colonoscopy. Medline Plus website. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/003886.htm. Accessed October 14, 2005.

National Digestive Diseases Information Clearinghouse website. Available at: http://www.gastro.org/. Accessed October 14, 2005.

Last reviewed November 2007 by Daus Mahnke, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.