Colonoscopy
Colonoscopy is the visual examination of the large intestine ( colon ) using a
lighted, flexible fiber optic or video endoscope. The colon begins in the
right lower abdomen and looks like a big question mark as it moves up and
around the abdomen, ending in the rectum. It is 5 to 6 feet long. The colon
has a number of functions
including withdrawing water from the liquid stool that enters it so that a
formed stool is produced.
Equipment
The flexible colonoscope is a remarkable piece of equipment that can be
directed and moved around the many bends in the colon. These colonoscopes now
come in two types. The original purely fiber optic instrument has a flexible
bundle of glass fibers that collects the lighted image at one
end and transfers the image to the eye piece. The newer video endoscopes use
a tiny, optically
sensitive computer chip at the end. Electronic signals are then transmitted up
the scope to a
computer which displays the image on a large video screen.
This is the type of instrument used in our office so the patient can see
exactly what the doctor sees.
An open channel in
these scopes allows
instruments to be passed through in order to perform biopsies, remove
polyps or inject solutions.
Reasons for the Exam
Directly viewing the inside of the colon by colonoscopy is usually
the best exam. Colonoscopy is used for :
Colon cancer - a serious but highly
curable malignancy
Polyps - fleshy tumors which usually are the forerunners of colon cancer
Colitis (Ulcerative or Crohn's) - chronic,
recurrent inflammation of the colon
Diverticulosis and Diverticulitis - pockets
along the intestinal wall that develop over time and can become infected
Bleeding lesions - bleeding may occur from different points in the colon
Abdominal symptoms, such as pain or
discomfort, particularly if associated with weight loss or anemia
Abnormal barium x-ray exam
Chronic diarrhea, constipation, or a change in bowel habits
Anemia
Preparation
To obtain the full benefits of the exam, the colon must be clean and free
of stool. The patient receives instructions on how to do this.
It involves drinking a solution which flushes the colon clean or taking
laxatives and enemas. Usually the patient drinks only clear liquids and eats
no food for the day before the exam.
The Procedure
Colonoscopy is usually performed on an outpatient basis. The patient is
mildly sedated, the endoscope is inserted through the anus and moved
gently around the bends of the colon. If a polyp is encountered, a thin wire
snare is used
to lasso it. Electrocautery ( electrical heat ) is applied to painlessly remove
it. Other tests can be performed during colonoscopy, including biopsy to
obtain a small tissue specimen for microscopic analysis.
The procedure takes 15 to 30 minutes and is seldom remembered by the sedated
patient. A recovery area is available to monitor vital signs until the patient
is fully awake. It is normal to experience mild cramping or abdominal pressure
following the exam. This usually subsides in an hour or so.
Results
After the exam, the physician explains the findings to the patient and family.
If the effects of the sedatives are prolonged, the physician may suggest an
appointment at a later date. If a biopsy has been performed or a polyp
removed, the results of these are not available for three to five days.
Benefits
A colonoscopy is performed to identify
and/or correct a problem in the colon. The test enables a diagnosis to be made
and specific treatment can be given. If a polyp is found during the exam, it
can be removed at that time, eliminating the need for a major operation later.
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