What is
Sigmoidoscopy?
Sigmoidoscopy is an internal
examination of the lower large bowel (colon), using an
instrument called a sigmoidoscope. The sigmoidoscope is a
small camera attached to a flexible tube. It is inserted
into the colon to examine the rectum, and the sigmoid and
descending portions of the colon.
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Effects
of Sigmoidoscopy
The benefits of sigmoidoscopy can include
the following:
-
It is often possible to determine the
specific cause of symptoms.
-
Conditions such as colitis and
diverticulosis can be monitored to
determine effectiveness of treatment.
-
Polyps and tumors can be discovered at
an early stage.
This test can help diagnose:
This test can also be used to:
-
Determine the cause of blood, mucus, or
pus in the stool
-
Confirm findings of another test or
x-rays
-
Take a biopsy of a growth
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Candidates
for Sigmoidoscopy
Sigmoidoscopy is performed to diagnose the
cause of certain symptoms. It is also used
as a preventative measure to detect problems
at an early stage, even before the patient
recognizes symptoms. The following are some
reasons for performing a Sigmoidoscopy:
Bleeding
-- Rectal bleeding is very common. It often
is caused by hemorrhoids or by a small tear
at the anus, called a fissure. However, more
serious problems can cause bleeding. Benign
polyps can bleed. It is important to
identify and remove polyps at an early stage
before they can become cancerous. Rectal and
colon cancers bleed and require immediate
diagnosis and treatment. Finally, various
forms of colitis and inflammation can cause
bleeding.
Diarrhea
-- Persistent diarrhea should always be
evaluated. There are many causes of diarrhea
and the exam is of great help in tracking
down the specific cause.
Pain
-- Hemorrhoids and fissures are some causes
of pain around the anus or in the rectum.
Discomfort in the lower abdomen can be
caused by tumors. Diverticulosis can occur
in the lower bowel. With this condition,
small pockets or sacks project from the
bowel.
X-ray Findings
-- A barium enema x-ray exam may show
abnormalities that need to be confirmed or
treated by sigmoidoscopy.
Detection
-- Colon cancer is one of the most common
cancers in the country. It is highly curable
if it is found early. This cancer usually
begins in the colon as a polyp that remains
benign for many years. Therefore, it is
generally advisable to have a sigmoidoscopy
after age 40 or 50. If parents, brothers, or
sisters have had colon polyps or colon
cancer, it is even more critical to have
this exam. The tendency to develop colon
cancer and polyps can be inherited.
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Your
Consultation
The colon and rectum must be completely
empty for flexible sigmoidoscopy to be
thorough and safe, so the physician will
probably tell you to drink only clear
liquids for 12 to 24 hours beforehand. A
liquid diet means fat-free bouillon or
broth, gelatin, strained fruit juice, water,
plain coffee, plain tea, or diet soda. The
night before or right before the procedure,
you may also be given an enema, which is a
liquid solution that washes out the
intestines. Your physician may give you
other special instructions.
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The Sigmoidoscopy
Procedure
During the test, you wear a hospital gown so
that the lower half of your body is exposed.
You are positioned on your left side with
your knees drawn up toward your chest.
A gastroenterologist (a specialist in
diseases of the digestive system) will
gently insert a gloved and lubricated finger
(or fingers) into the rectum to check for
blockage and to dilate the anus. This is
called a digital rectal examination.
Following the digital rectal exam, the
sigmoidoscope will be inserted. This
flexible fiberoptic tube is about 20 inches
long.
The scope is gently advanced into the colon.
Air is introduced into the scope to aid in
viewing. The air may cause the urge to
defecate. As the sigmoidoscope is slowly
removed, the lining of the bowel is
carefully examined. A channel in the scope
allows for the passage of forceps for
biopsies or other instruments for
therapy.
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Recovery
After the procedure, you may experience mild
abdominal cramping and gas as a result of
the air that was placed in your intestine.
Some people may have slight
rectal bleeding due to minor
irritation and trauma from the insertion of
the sigmoidoscope. After the procedure, you
will be taken to a recovery area so you can
change into your clothing and receive
discharge instructions. You will be able to
drive yourself home.
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Risks
Although generally considered quite safe,
sigmoidoscopy does carry the very rare
possibility of tearing of the intestinal
wall by the instrument, which would require
immediate major surgery to repair the tear;
in addition, removal of a polyp may
sometimes lead to localized bleeding which
is resistant to cauterization by the
instrument and must be stopped by surgical
intervention.
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Frequently Asked
Questions
Q: What is a Sigmoidoscopy?
A:
Inspection of the rectum and lower colon
using a thin lighted tube called a
sigmoidoscope. Samples of tissue or cells
may be collected for examination under a
microscope. Also called proctosigmoidoscopy.
Q: How will the test feel?
A:
There will be pressure when the scopes or
fingers are introduced into your rectum.
There will be a feeling of the need to
defecate during the procedure. There may be
some bloating or cramping from distention of
the bowel by air or stretching by the
sigmoidoscope. Biopsies cause no discomfort.
After the test, you will expel the air that
was introduced.
Q: What are the types of Sigmoidoscopy?
A:
There are two types of sigmoidoscopy,
flexible sigmoidoscopy, which uses a
flexible
endoscope, and rigid
sigmoidoscopy, which uses a rigid device.
Flexible sigmoidoscopy is today generally
the preferred procedure.
Q: What is Flexible
Sigmoidoscopy?
A:
Flexible sigmoidoscopy enables the
physician to look at the inside
of the large intestine from the rectum
through the last part of the colon, called
the sigmoid or descending colon. Physicians
may use the procedure to find the cause of
diarrhea,
abdominal pain, or
constipation. They also use it to
look for benign and malignant
polyps, as well as early signs of
cancer in the descending colon
and rectum. With flexible sigmoidoscopy, the
physician can see
intestinal bleeding,
inflammation, abnormal growths,
and
ulcers in the descending colon
and rectum. Flexible sigmoidoscopy is not
sufficient to detect polyps or cancer in the
ascending or transverse colon (two-thirds of
the colon).
Q: What is Rigid
Sigmoidoscopy?
A:
Rigid sigmoidoscopy has no longer the value
it had in the past, before the advent of
videocolonoscopy (flexible sigmoidoscopy).
However, it may be still useful in ano-rectal
diseases such as bleeding per rectum or
inflammatory rectal disease, particularly in
the general practice and pediatrics.
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