Colonoscopy - What to Expect

March 18, 2013
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During this podcast, you'll receive some key facts about colonoscopy and an explanation of what happens during this test, to help you prepare for your own colonoscopy. You will also be offered a list of questions to ask your doctor about your test and its results.


You’re listening to a podcast from Cancer.Net. This cancer information website is produced by the American Society of Clinical Oncology, known as ASCO, the world’s leading professional organization for doctors that care for people with cancer.

Today we’ll discuss what to expect when you are scheduled to have a colonoscopy. In this podcast, you’ll receive some key facts and an explanation of what happens before, during and after this test. You’ll also be offered a list of questions to ask your doctor about your test and its results.                                        

A colonoscopy is an exam that allows a doctor to look inside the entire large intestine, which is important for the body to process waste. The large intestine is made up of colon and rectum, ending at the anus.

A colonoscopy is used to diagnose the cause of a problem a person is having in the colon or rectum, as well as a routine screening test for colorectal cancer for people who have no symptoms. Usually, a colonoscopy is given by a gastroenterologist with the help of a nurse. A gastroenterologist specializes in the problems and diseases of the digestive system, including the colon and rectum.

Before the colonoscopy, you will be given pain medication and a sedative, which is a medication that causes drowsiness to reduce discomfort. Then, the doctor will insert a colonscope into the anus and throughout the full length of the colon. A colonoscope is a tiny, flexible tube with a light and camera. The doctor views the images made by the colonoscope on a video monitor. During the procedure, the doctor may also remove a small amount of tissue to examine under a microscope, called a biopsy.

Now that you know what a colonoscopy is and who will perform the examination, let’s discuss how to prepare for the procedure.

When you schedule the examination, you will get detailed instructions on how to prepare for your colonoscopy. Tell your doctor or nurse about all the medications you’re taking and ask them whether you should take your regular medications on the day of the test. Also, tell your doctor about any drug allergies or medical conditions you have.

Your colon must be completely empty for a colonoscopy, which means you will need to avoid solid food and drink only clear liquids for one to three days before the procedure. That means eating only foods such as fat-free bouillon or broth, black coffee, strained fruit juice, and gelatin.

In addition to the liquid diet, you’ll also need to take a laxative, which is a medication that causes bowel movements. Or you may need to give yourself an enema, which is a process that involves injecting liquid into your anus to cause bowel movements. Generally, you’ll need to do this the day or night before the colonoscopy. If your doctor prescribes a laxative, it will either be given as a pill or as a powder that you’ll mix with water before drinking. In either form, the laxative will make you use the bathroom frequently. Completely cleansing your bowel will ensure a thorough examination.

When preparing for the exam, it’s important to arrange for a friend or family member to drive you home after the procedure because you’ll be groggy from the sedative. Also, make sure to check you insurance coverage beforehand, including whether it covers the medical facility, doctor, and anesthesiologist, if an anesthesiologist will be involved in the sedation. Before the procedure, you will be asked to sign a consent form that states you understand the risks and benefits of having the colonoscopy and agree to have the test. Be sure to talk with your doctor about any concerns you have about this exam.

When you arrive for a colonoscopy, you’ll need to remove your clothing and change into a hospital gown. During the exam, you’ll need to lie on your side on an examining table in a private room with a sheet draped over you.

Before the procedure begins, a nurse will give you the pain medication and a sedative through an intravenous, or IV, line in your arm. You might feel a slight stinging where the IV needle is inserted, but the medications will help you relax and reduce the discomfort you might otherwise feel from the colonoscopy.  

During the procedure, the doctor inserts the colonoscope into the anus. Then, the colonoscope inflates your colon by blowing air into it. This provides the doctor with a better view of the colon lining. As the doctor guides the colonoscope through the curves of your colon, you may need to change your position slightly to allow your doctor better access.

The procedure usually takes 30 to 60 minutes to complete.

Generally, the pain medicine and sedative should limit the discomfort you might experience. But you may feel cramping during the test. Taking slow, deep breaths may relieve this discomfort. You may also feel discomfort from lying still for an extended period of time.

Though rare, there is a risk that the colonoscope could puncture the colon wall, and surgery may be needed to repair the hole. Talk with your doctor if you have any concerns about this small risk.

After the exam is finished, you will need to stay at the facility where you had the test for up to two hours while the effects of the sedative wear off, and then a friend or family member can drive you home. You can expect to resume your normal activities the day after your colonoscopy. However, if you feel severe abdominal pain, have a fever or bloody bowel movements, or are dizzy or weak following a colonoscopy, call your doctor immediately.

Before having a colonoscopy, consider asking your doctor the following five questions, along with discussing any concerns you may have about the test:

Question number one: Who will perform the colonoscopy, and what will happen during the examination?

Question two: How long will the procedure take, and will it be painful?

Question three: What are the risks associated with having a colonoscopy?  And, what are the risks of not having the test?

Question four: When and how will I get the test results, and who will explain them to me?

And question five: What happens next if a polyp or abnormality is found during the test, and will I need additional tests?

Now that you know what to expect before having a colonoscopy, you’ll hopefully feel more comfortable with having this important test.

For more information on colonoscopies, talk with your doctor or visit Cancer.Net is supported by the Conquer Cancer Foundation, which is working to create a world free from the fear of cancer by funding breakthrough research, sharing knowledge with physicians and patients worldwide, and supporting initiatives to ensure that all people have access to high-quality cancer care. Thank you for listening to this Cancer.Net podcast.