A screening colonoscopy
is a good idea for those aged 50 years and above (younger for individuals with a family
history of colorectal cancer). It may also be recommended for those who display symptoms suggesting problems in the
colon Or rectum, such as bleeding, change in bowel habits and unexplained abdominal symptoms. The procedure is used
as well for follow up examinations of patients with a history of colon cancer or polyps.
Preparing for the scope
The patient will be given potent laxatives to clear the colon of stools. In most cases, if the procedure is to be done
in the morning, the patient will be asked to take the laxatives and purge the night before. For an afternoon procedure,
expect to be asked to clear the bowels on the morning of the examination.
To help clear the bowels, patients will be encouraged to take in as much fluid in their diet as possible. Foods high in
fibre like fruit and vegetables, however, are discouraged, starting two days prior to the colonoscopy. Patients who are
on aspirin or other blood thinning medications will also be
advised by the doctor
when to stop those medications.
Multiple trips to the toilet should be expected after the laxatives have been ingested. Many patients have expressed
that this is the worst part of the entire procedure.
The big day
Many people fear colonoscopy because of the perception that it is a highly invasive and painful process. The truth is,
most patients do not experience any pain or even remember much about the procedure after they wake up from sedation.
The sedative is administered via injection, although there are patients who choose to remain conscious and experience
the procedure ‘live’. This is also possible as the main discomfort comes from bloatedness and the urge to pass motion,
and not actual pain.
After the patient is sedated, the doctor will insert the colonoscope via the anus and advance it up the rectum and along
the colon. The scope goes up along the left side of the abdominal cavity until it reaches just below the ribcage. It is
then turned to and through the right side, before it is directed to the right lower part of the abdomen, until it
reaches the end of the colon, where the openings of the appendix and small intestines are. In certain cases, the doctor
may advance the scope through the ileocaecal valve (junction of the small intestines and the colon) to inspect the last
part of the ileum.
Pros and cons
One of the biggest advantages of colonoscopy over other methods of colon examination is that it allows direct
visualisation and does not merely rely on indirect imaging techniques. It also allows any adherent stools to be washed
away so that the colon lining beneath is visible. It is also the only technique that enables tissues to be removed for
biopsies and for polyps to be removed.
Side effects from a colonoscopy are rare. The most serious complication that can occur is colonic perforation, but the
risk is less than 1 in 1,000, or 0.1%. A perforation or tear in the colon wall may be caused by direct trauma of the
colonoscope or a delayed perforation after the removal of a polyp. Surgery is typically required to rectify the problem.
Most people, however, do not encounter any side effects. Some patients may feel bloated because of residual air left in
the colon. It is also normal to have less bowel movements over the subsequent days because of the amount of stools that
have been cleared out during the preparation stage.