Colonoscopy
Medical Author:
Eric Lee, M.D.
Medical Reviewing Author/Editor:
Dennis Lee, M.D.
What is colonoscopy?
Colonoscopy is a procedure that enables an examiner (usually a gastroenterologist) to evaluate the appearance of the inside of the colon (large bowel). This is accomplished by inserting a flexible tube that is about the thickness of a finger into the anus, and then advancing it
slowly, under visual control, into the rectum and through the
colon. It is
performed with the visual control of either looking through the
instrument
or with viewing a TV monitor.
Why is colonoscopy done?
This test may be done for a variety of reasons. Most often it
is done to
investigate the finding of blood in the stool, abdominal pain,
diarrhea, a
change in the bowel habits, or an abnormality found on colon x-
ray or a
CT scan. Certain individuals with
previous history of polyps or colon cancer and certain individuals with family history of particular
malignancies or colon problems may be advised to have periodic
colonoscopies because they are at a greater risk of polyps or
colon
cancer.
What bowel preparation is needed for colonoscopy?
If the procedure is to be complete and accurate, the colon
must be
completely clean. Patients are given detailed instructions
about the
cleansing of the colon procedure. In general this consists of a
large
volume of a special cleansing solution or several days of a
clear liquid
diet and laxatives or enemas prior to the examination. These
instructions
should be followed to the letter or the procedure may be
unsatisfactory
and have to be repeated later or a less accurate alternative
chosen in its
place.
What about current medications or diet before
colonoscopy?
Most
medications should be continued as usual, but some may interfere with the
examination. It is best that the physician is informed of all current
prescription or over the counter medications. Aspirin products, blood thinners
(Coumadin, etc.), arthritis medications,
insulin, and iron
preparations are examples of medications that may require
special
instructions. The physician will also want to be aware of the
patient's
allergies and any other major illnesses. The examiner should be
alerted
if, in the past, patients have required antibiotics prior to
surgical or
dental procedures. Instructions may also be given to avoid
certain foods
for a couple of days prior to the procedure, such as stringy
foods, foods
with seeds, or red Jello.
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