Colonoscopy

A Colonoscopy is a procedure that enables a physician, doctor or gastroenterologist to examine the lining of the rectum and colon in order to determine whether there are any growths, ulcers, erosions or inflammation. It is usually done in hospital or in an endoscopic procedure room. A soft, bendable tube with a miniature camera is gently inserted into the anus and advanced into the rectum and to the colon. A colonoscopy is a safe procedure that provides information other tests may not be able to give.

When would a colonoscopy be done?
The most common reasons for a colonoscopy are to evaluate any of the following:

• blood in the stool or rectal bleeding;
• dark/black stools;
• persistent diarrhoea;
• iron deficiency anaemia (a decrease in blood count due to loss of iron);
• significant, unexplained weight loss, accompanied by gastrointestinal symptoms;
• a family history of colon cancer;
• to follow up an abnormal barium enema (x-ray examination of large intestine);
• a history of previous colon polyps (growths on the colon) or colon cancer;
• surveillance in people with ulcerative colitis;
• for the medical management of chronic inflammatory bowel disease;
• chronic, unexplained abdominal pain; and
• as a screening exam for colon cancer in anyone over the age of 50.

What preparations are required before the procedure?
The rectum and colon must be completely emptied of stool in order for the procedure to be performed. The doctor staff will provide you with instructions on how your doctor would like you to prepare for the procedure. The instructions are designed to maximise safety during and after the examination, minimise possible complications and allow the doctor to fully view the colon.

You should not eat any solid food for at least one day before the examination. Only clear liquids are recommended. The bowel-cleansing regimen involves drinking a large volume of an indigestible solution that causes temporary diarrhoea. It comes in several flavours that unfortunately only partially mask a somewhat unpleasant taste. Refrigerating the solution may make it more pleasant. Drinking such a large volume of cold solution may cause you to feel chilled, but the sensation is only temporary. Do not add flavouring to the solution.

Follow your doctor's instructions carefully. If you are unable to take the solution, contact your doctor.

Your chronic medication can be continued as usual. Other medication use, such as aspirin, non-steroidal, anti-inflammatory drugs, iron tablets, herbal remedies, blood thinners and insulin should be discussed with your doctor prior to the examination.
 
It is important to advise your doctor if you have any of the following:

• allergies to any drugs;
• allergy to x-ray contrast media (dye);
• a pacemaker;
• a joint replacement; and
• a heart valve replacement.

Just before the procedure, you will be given a light anaesthetic and a pain tablet. You will therefore be sedated during the procedure and an arrangement to have someone drive you home afterward is important.

How is the procedure performed?
The procedure is generally well tolerated by patients, although you might feel some pressure, bloating or cramping during the procedure. You will be lying on your side or on your back while the colonoscopy is advanced through the large intestine. The lining of the colon is examined carefully while inserting and withdrawing the instrument. The procedure usually lasts between 15 and 60 minutes.

Should your doctor see an area that needs more detailed evaluation, a biopsy may be obtained and submitted to a laboratory for analysis. Polyps (abnormal growths of tissue) are generally removed. The majority of polyps are benign (non-cancerous), but your doctor cannot always tell by their appearance alone. They can be removed by burning or by a wire loop (snare). Sites of bleeding can be identified and controlled by injecting certain medication or coagulating (burning) the bleeding vessels. These procedures do not cause any pain. Biopsies are used to identify many conditions and your doctor may take a biopsy, even if cancer is not thought to be the problem.

What happens after the procedure?

• You will be observed until most of the effects of the sedation have worn off (one to two hours). However, you will need someone to drive you home after the procedure.
• You may have some mild cramping or bloating from the air that was placed into the colon during the examination. This will improve with the passing of gas.
• You should be able to eat normally the same day after leaving the hospital.
• Do not drive or operate machinery until the next day, as the sedatives given will impair your reflexes.
• Your doctor will tell you what was found during the examination. Alternatively you may need to go back for a follow-up appointment to discuss the results and those of any biopsies performed.
• If polyps were found during your procedure, you will need to have a repeat colonoscopy. Your doctor will decide on the frequency of your colonoscopy exams.

What complications can occur?
Even though complications are rare, they can occur. They include bleeding from the site of a biopsy or polypectomy and a tear (perforation) through the lining of the bowel wall. Should this occur, it may be necessary for your doctor to perform abdominal surgery to repair the intestinal tear. A reaction to the sedatives can also occur.

Mild pain and discomfort may be experienced in the abdomen for one or two days after the procedure. This is treated with analgesia. It usually settles without further treatment. It is important to contact your doctor if you notice symptoms of severe abdominal pain, fevers, chills or rectal bleeding of more than half a cup. Bleeding can occur up to several days after a biopsy.

References
UPTODATE. Patient Information.2014