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The What, Why and How of A Colonoscopy

Updated on September 7, 2008

Charles Barkley, former NBA star, was to have a televised colonoscopy as part of the upcoming "Stand Up to Cancer" event that will be simulcast on CBS, NBC and

Via Sports Media Watch, Dan Gross at the Philadelphia Daily News reported that Charles Barkley, former NBA star, was to have a televised colonoscopy as part of the upcoming "Stand Up to Cancer" event that will be simulcast on CBS, NBC and ABC, on 5 Sept 08. As I don’t live in the States and know NBA as much as my readers know about Tai-Chi, I have yet to find out whether the procedure or the broadcast actually took place. Nonetheless, the colonoscopy is relevant even to you. This article explains the what, why and how of a colonoscopy.

What is a colonoscopy?

A colonoscopy allows the surgeon or gastroenterologist to look inside the entire large bowel (includes cecum, colon and rectum). The procedure will help detect presence of inflamed tissue, abnormal growths, and ulcers. It is most often performed to screen for cancer in the colon and rectum. It is also used to investigate for causes of changes in bowel habits, abdominal pain, rectal bleeding, and weight loss.

What is the colon?

The colon, or large bowel, is the last portion of your digestive tract. The colon is an elastic muscular tube that starts at the end of the small intestine and ends at the rectum and anus. It is about 1.3m long. It helps the digestive tract is to store unabsorbed waste of food and absorb fluids before the waste is excreted as stool.

Bowel Preparation

You will be given instructions to explain what to do to prepare for your colonoscopy. Your colon must be completely empty for the colonoscopy to be safe and accurate. To prepare for the procedure you will have to follow a low residue diet on day 1 of your bowel preparation and then a liquid diet on day 2. Low residue diet means no fruit, vegetables, meat (with the exception of fish) is allowed. The liquid diet should be clear and not contain food colorings, and may include plain coffee, tea, juice, broth, and gelatin.

Thorough cleansing of the bowel is necessary on the night prior to the colonoscopy. You are asked to take a laxative to achieve this. While this laxative used to be 2 liters of a liquid, this has now been replaced by a 90cc volume of a laxative liquid. You have to inform your doctor about your medical conditions that require medications including aspirin, arthritis drugs, blood thinners, diabetic drugs and iron supplements. You also need to inform your doctor about your medical conditions including heart disease, lung disease, or any medical condition that may need special attention. You must also arrange for someone to accompany you home. Make sure you don’t drive or operate machines after being sedated for the procedure.

The Procedure

For the colonoscopy, you will lie on your left side on the examining table. You will be given an intravenous pain killer and a sedative to lessen your discomfort and apprehension. Your doctor and his staff will monitor your vital signs and make sure you are OK throughout the procedure.

The doctor will then insert a 2m long, bandable, tube (called a colonoscope) into your rectum. This is gently manipulated up to the top of your colon. The scope transmits the image inside your colon onto a video screen. Because of the sedative used, most patients do not remember the procedure afterwards.

Abnormal growths in your colon, including polyps are removed using tiny tools passed through the scope. Most polyps are benign (not cancerous). However, some of these, especially the larger ones, can turn into cancer. The polyps are sent for testing. By identifying and removing polyps, a colonoscopy prevents large bowel cancers from forming.

The doctor can also remove tissue samples to test in the lab for diseases of the colon (biopsy). In addition, if any bleeding occurs in the colon, the doctor can pass a laser, heater probe, electrical probe, or special medicines through the scope to stop the bleeding. The tissue removal and treatments to stop bleeding usually do not cause pain. In many cases, a colonoscopy allows for accurate diagnosis and treatment of colon abnormalities without the need for a major operation. Bleeding and puncture of the colon are possible but uncommon complications of a colonoscopy. A colonoscopy usually takes 30 to 60 minutes. Some cramping or bloating of the abdomen is common following the procedure. You will need to sleep off your sedation for 1 to 2 hours before you are allowed to go home.

The Post-operative Night

Rarely, symptoms including severe abdominal pain, fever, bleeding in stools, sweating and dizziness may occur afterward. Should these happen, contact your surgeon or gastroenterologist immediately. Most patients recover fully within one day to resume their usual activities.

Dr Benson Yeung's related hubs:

Why do you need colorectal cancer screening

The Newest Screening Test For Large Bowel Cancer


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    • Benson Yeung profile image

      Benson Yeung 7 years ago from Hong Kong

      Hi okmom23,

      thanks for dropping by and commenting.

    • okmom23 profile image

      Donna Oliver 7 years ago from Midwest, U.S.A.

      Very informative hub. I just had a screening 3 weeks ago and I am glad I did! Thank you for such a clear explanation of the procedure.

    • Benson Yeung profile image

      Benson Yeung 8 years ago from Hong Kong

      Hi TINA V

      thanks for commenting. It's not a matter of how much but what other symptoms the patient has, as well as his / her age, as well as family history of cancer.

    • TINA V profile image

      TINA V 8 years ago

      This is an informative hub. I have read an article that rectal bleeding can stop by using suppositories. I was just wondering up to what extent of the bleeding that colonoscopy will already be recommended. Thanks for sharing.

    • Benson Yeung profile image

      Benson Yeung 9 years ago from Hong Kong

      Dear Moon Daisy,

      thanks for commenting.

    • Moon Daisy profile image

      Moon Daisy 9 years ago from London

      Nice article. (I love the photo!)

    • Benson Yeung profile image

      Benson Yeung 9 years ago from Hong Kong

      Hi Stacie,

      thanks for commenting.

    • Stacie L profile image

      Stacie L 9 years ago

      this is a very important screening,and everyone should have it by age 50 ,if there no problems.Totally painless!

    • Benson Yeung profile image

      Benson Yeung 9 years ago from Hong Kong

      Hi Shirley,

      the extent of sedation given varies with the unit delivering the colonoscopy. Only the most common practice is outlined here. Thanks for commenting.


    • Shirley Anderson profile image

      Shirley Anderson 9 years ago from Ontario, Canada

      Hi Benson. One of my daughter's has Crohn's Disease, so I'm very familiar with what happens. What I don't understand is why some people get 'put out' for it, and some don't. My daughter was given something to relax her, but never put to sleep for the colonoscopies that she's had over the years.

      Very nicely informative article, Benson.

    • Shadesbreath profile image

      Shadesbreath 9 years ago from California

      Is that what it's really about? "Getting" mad?

    • Benson Yeung profile image

      Benson Yeung 9 years ago from Hong Kong

      Thanks, Shadesbreath. You are only forty one years young. You can elect to have your first pleasurable experience at the age of 50 if you have no symptoms and no family history.

      I am thinking of editing my series and rename it "getting mad". What do you think?

    • Shadesbreath profile image

      Shadesbreath 9 years ago from California

      I went to find the part 1 of your getting mad series and saw this. I'm forty one and everyone keeps talking about these things and telling me I'm supposed to work one in, as it were, now that I'm "of that age." Can't say this article makes me any less terrified of the prospect, but at least I know a bit more. Good job covering the basics here.