Gastroenterology Center

Patient Education

Colonoscopy

What is a colonoscopy?
A colonoscopy is an exam of the colon (large intestine, or bowel) with a slim, flexible, lighted tube called a colonoscope. Your health care provider can use the colonoscope to get a clear, magnified view of the inside of your colon from the anus to the area near the appendix.

When is it used?
Colonoscopy is the most direct and complete way to see the entire lining of the colon. It is usually done for one of the following reasons:

  • Prevention and early detection of cancer. If you are between 50 and 80 years old, your health care provider may recommend that you have a colonoscopy every 10 years. If you have a personal or family history that increases your risk, your provider may recommend that you have the test more often. A colonoscopy can help your provider find and remove growths (polyps) before they become cancerous. It can also allow your provider to detect cancerous growths early, when the cancer is easier to cure.
  • Diagnosis of illness. If you have symptoms of illness that your health care provider has not been able to explain, you may have this procedure to try to find the cause of your symptoms. For example, you may be having unexplained abdominal pain or abnormal bowel movements. Your provider can check for inflammation of the bowel lining or infected pockets (diverticula) in the bowel wall.

How do I prepare for a colonoscopy?
Follow your health care provider's instructions about not smoking before and after the procedure.

  • If you need a minor pain reliever in the week before the procedure, choose acetaminophen rather than aspirin, ibuprofen, or naproxen. This helps avoid extra bleeding during the procedure. If you are taking daily aspirin for a medical condition, ask your provider if you need to stop taking it before the procedure.
  • Your health care provider will give you written instructions on how to clear bowel movements from the colon.
  • You will probably be asked to eat no solid food for 24 to 48 hours before the exam.
  • You should have only clear liquids 12 to 24 hours before your exam. Clear liquids are water, broth, apple or white grape juice, tea or coffee (no milk or cream), and soda. Gelatin in any color but red may also be eaten.
  • You will be asked to take a liquid laxative and may be asked to give yourself a home enema a few hours before your exam. This will clear stool from the bowel. Be sure to complete this bowel preparation. The exam may not be possible if the colon still has stool in it.

Drink plenty of clear liquids during the bowel preparation to avoid dehydration. It is helpful to drink liquids that help replace the electrolytes (potassium and sodium) you lose during the prep. Unless otherwise instructed, you can continue taking your usual medicines.

Tell your provider if:

  • You have any allergies.
  • You are taking any medicines, especially aspirin or anticoagulants (blood thinners).
  • You need to take antibiotics before dental procedures because of heart valve disease or implanted devices, such as artificial joints.

The test takes 20 to 30 minutes. However, you will need to plan on being at the doctor's office or clinic for a total of about one and a half to two hours for check-in, the exam, and recovery. You should arrange for someone to drive you home after the exam.

What happens during the procedure?
A colonoscopy may be done in the doctor's office or in an outpatient clinic.

Just before your exam, you may be given a sedative, which will help relax you. You may be given this medicine with a needle in your vein (IV).

You will lie on a table on your side with your knees bent and drawn up to your stomach. Or your doctor may use a special table that allows you to rest your belly on the table as you kneel on the step in front of it. The table can then be tilted or raised. These positions make it easier for the doctor to pass the colonoscope into your anus and rectum and up into your colon.

The doctor can view the images of the colon on a TV monitor. As the scope is passed through your colon, air is pumped into the colon so your doctor can see as much of the walls of the colon as possible. This air may make you feel bloated and give you cramps.

If your doctor sees anything abnormal during the exam, he or she may take small samples of tissue through the colonoscope for lab tests. The doctor may be able to remove any abnormal areas, polyps, or small tumors from the colon through the colonoscope. This may help you avoid having another procedure to remove them.

What happens after the procedure?
After the doctor removes the scope, you may rest at the doctor's office or the clinic until you are awake and alert enough to be driven home. You should plan on continuing to rest for a few hours after you get home. It is normal to have intestinal gas and mild cramps for a few hours after the exam. After resting you should feel like eating a normal diet again. Be sure to drink lots of fluids after the test.

If polyps or other tissue is removed, you may notice a small mount of blood in your stools for a short time.

Before you have the exam, ask your health care provider when and how you will be informed of the results. Someone may call you or you may need to call or make a follow-up appointment to get the results.

What are the benefits of this procedure?
This procedure helps your health care provider diagnose problems in the colon. For some problems, such as cancer, treatment is more effective when the problem is detected early.

What are the risks associated with this procedure?
Risks include:

  • some pain or swelling in your lower abdomen if air was pumped into your intestine during the procedure (this will last until your body passes the extra air shortly after the procedure)
  • damage to the colon (perforation) from the colonoscope and possible infection, which may then require surgery for repair
  • bleeding inside the colon, which also may need surgery.

When should I call my health care provider?
Call your provider right away if:

  • You have severe abdominal pain or rectal bleeding.
  • Pain or symptoms you had before the procedure become worse.

Call during office hours if:

  • You have questions about the procedure or its results.
  • You want to make another appointment.