What is
Colonoscopy?
A
colonoscopy allows a doctor to look inside the entire large
intestine. The procedure enables the physician to see things
such as inflamed tissue, abnormal growths, and ulcers. It is
most often used to look for early signs of cancer in the
colon and rectum. It is also used to look for causes of
unexplained changes in bowel habits and to evaluate symptoms
like abdominal pain, rectal bleeding, and weight loss.
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Effects
of Colonoscopy
Colonoscopy is the best test available to detect and treat
abnormalities within the colon.
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Candidates
for Colonoscopy
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
CAT 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.
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Your
Consultation
You will be
given instructions in advance that will
explain what you need to do to prepare for
your colonoscopy. Your colon must be
completely empty for the colonoscopy to be
thorough and safe. To prepare for the
procedure you will have to follow a liquid
diet for 1 to 3 days beforehand. The liquid
diet should be clear and not contain food
colorings, and may include
Thorough cleansing of the bowel is necessary
before a colonoscopy. You will likely be
asked to take a laxative the night before
the procedure. In some cases you may be
asked to give yourself an enema. An enema is
performed by inserting a bottle with water
and sometimes a mild soap in your anus to
clean out the bowels. Be sure to inform your
doctor of any medical conditions you have or
medications you take on a regular basis.
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The Colonoscopy
Procedure
For the
colonoscopy, you will lie on your left side
on the examining table. You will be given
pain medication and a moderate sedative to
keep you comfortable and help you relax
during the exam. The doctor and a nurse will
monitor your vital signs, look for any signs
of discomfort, and make adjustments as
needed.
The doctor
will then insert a long, flexible, lighted
tube into your rectum and slowly guide it
into your colon. The tube is called a
colonoscope (koh-LON-oh-skope). The scope
transmits an image of the inside of the
colon onto a video screen so the doctor can
carefully examine the lining of the colon.
The scope bends so the doctor can move it
around the curves of your colon.
You may be
asked to change positions at times so the
doctor can more easily move the scope to
better see the different parts of your
colon. The scope blows air into your colon
and inflates it, which helps give the doctor
a better view. Most patients do not remember
the procedure afterwards.
The doctor can
remove most abnormal growths in your colon,
like a polyp, which is a growth in the
lining of the bowel. Polyps are removed
using tiny tools passed through the scope.
Most polyps are not cancerous, but they
could turn into cancer. Just looking at a
polyp is not enough to tell if it is
cancerous. The polyps are sent to a lab for
testing. By identifying and removing polyps,
a colonoscopy likely prevents most 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.
During the
procedure you may feel mild cramping. You
can reduce the cramping by taking several
slow, deep breaths. When the doctor has
finished, the colonoscope is slowly
withdrawn while the lining of your bowel is
carefully examined. Bleeding and puncture of
the colon are possible but uncommon
complications of a colonoscopy.
A colonoscopy usually takes 30 to 60
minutes. The sedative and pain medicine
should keep you from feeling much discomfort
during the exam. You may feel some cramping
or the sensation of having gas after the
procedure is completed, but it usually stops
within an hour. You will need to remain at
the colonoscopy facility for 1 to 2 hours so
the sedative can wear off.
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Recovery
Patients will be kept in an observation area
for an hour or two, until any medication
given adequately wears off. If they have
been given sedation before or during the
procedure, someone must take them home, even
if they feel alert. The patient's reflexes
and judgment may be impaired for the rest of
the day, making it unsafe to drive or
operate any machinery. Should patients have
some cramping or bloating this should be
relieved quickly with the passage of gas and
they should be able to eat upon the
returning home. After the removal of polyps
or certain manipulations, the diet or
activities of patients may be restricted for
a brief period of time.
Medications such as blood-thinners may need
to be stopped for a short time after having
your colonoscopy, especially if a biopsy was
performed or polyps were removed. Full
recovery by the next day is normal and
expected and you may return to your regular
activities.
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Risks
Rarely, some people experience severe
abdominal pain, fever, bloody bowel
movements, dizziness, or weakness afterward.
If you have any of these side effects,
contact your physician immediately.
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Frequently Asked
Questions
Q: What is colonoscopy?
A:
Colonoscopy is a test that allows your
doctor to look at the interior lining of
your
large intestine (rectum
and colon) through a thin, flexible viewing
instrument called a colonoscope. A
colonoscopy helps detect
ulcers,
polyps, tumors, and areas
of inflammation or bleeding.
Q: What is a colonoscope?
A:
The colonoscope is a thin, flexible
instrument that ranges from 48 in.(121.9 cm)
to 72 in.(182.9 cm) long. A small video
camera is attached to the colonoscope so
that photographic, electronic, or videotaped
images of the large intestine can be made.
In some cases, the colonoscope may use fiber
optics. However, digital video technology
has generally replaced fiber optics. The
colonoscope can be used to view the entire
colon as well as a small portion of the
lower small intestine.
Q: What should I do to prepare for a
colonoscopy?
A:
Before this test, you will need to clean out
your colon (colon prep). Colon prep takes 1
to 2 days depending on which type of prep
your doctor recommends. Some preps may be
taken the evening before the test. For many
people, the prep for a colonoscopy is more
trying than the actual test. Plan to stay
home during your prep time since you will
need to use the bathroom frequently. The
colon prep causes loose, frequent stools and
diarrhea so that your colon will be empty
for the test. The colon prep may be
uncomfortable and you may feel hungry on the
clear liquid diet. If you need to drink a
special solution as part of your prep, be
sure to have clear fruit juices or soft
drinks to drink after the prep because the
solution tastes salty.
Q: Why is this test necessary?
A:
Colonoscopy is needed for the following
reasons:
-
To obtain tissue specimen for biopsy
-
To evaluate unexplained anemia
-
To evaluate unexplained
blood in the stool, abdominal
pain, persistent diarrhea, or
abnormalities (such as polyps) found on
contrast x-rays (barium
enema)
-
To determine the type and extent of
inflammatory bowel disease (ulcerative
colitis and
Crohn's disease)
-
To follow a previous finding of
polyps,
colon cancer, or a family
history of colon cancer
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