Anoscopy, proctoscopy, and sigmoidoscopy tests
allow your health professional to look at the inner lining of your
anus,
rectum, and the lower part of the
large intestine (colon). These tests are used to look for abnormal growths
(such as tumors or
polyps), inflammation, bleeding,
hemorrhoids, and other conditions (such as
diverticulosis).
These test use different
scopes look at different sections of the colon.
Anoscopy. During an anoscopy, a short,
rigid, hollow tube (anoscope) that may contain a light source is used to look
at the last
2 in. (5 cm) of the
colon (anal canal). Anoscopy can usually be done at any time because it does
not require any special preparation (enemas or laxatives) to empty the
colon.
Proctoscopy. During a proctoscopy, a
slightly longer instrument than the anoscope is used to view the inside of the
rectum. You usually will have to use enemas or laxatives to empty the colon
before the test is done.
Sigmoidoscopy.
During a sigmoidoscopy, a lighted tube that may be either rigid or flexible is
inserted through the anus. Your health professional can remove small growths
and collect tissue samples (biopsy) through a sigmoidoscope. You
will have to use enemas or laxatives (or both) to empty the colon before the
test is done.
The flexible sigmoidoscope is about
2.3 ft (70 cm) long and
0.5 in. (1 cm) wide with a
lighted lens system. This instrument allows your health professional to see
around bends in the colon. A flexible sigmoidoscope allows a more complete view
of the lower colon than a rigid scope and usually makes the examination more
comfortable. The flexible sigmoidoscope generally has replaced the rigid
sigmoidoscope.
The rigid sigmoidoscope is used less often. It is about
10 in. (25 cm) to
12 in. (32 cm) long and
1 in. (2.5 cm) wide. It allows
your health professional to look into the rectum and the bottom part of the
colon, but it does not reach as far into the colon as the flexible
sigmoidoscope.
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Decision Points focus on key medical care decisions that are important to many health problems.
Detect problems or diseases of the anus,
rectum, or lower large intestine (sigmoid colon). These tests are often done to
investigate symptoms such as unexplained bleeding from the rectum, long-lasting
diarrhea or constipation, blood or pus in the stool, or lower abdominal
pain.
Usually, no preparation is needed for an
anoscopy.
Proctoscopy and sigmoidoscopy
Test preparation for
a proctoscopy and
sigmoidoscopy may be similar. Before the test:
Talk with your health professional to find
out if you need to stop taking some medicines, such as warfarin, before the
test.
Talk with your health professional to find out if you need to
take antibiotics before the test, especially if you have a
heart murmur, an artificial heart valve, or an
artificial implant (such as a replacement joint).
The preparation for these tests usually involves a
thorough cleaning of the lower colon, because it must be completely clear of
stool (feces). Even a small amount of fecal material can affect the accuracy of
the test.
You may be instructed to follow a
liquid diet for 1 to 2 days before the
test.
You may be instructed to not eat for up to 12 hours before
the test.
You may need to have an enema the night before the test
and another enema an hour before the examination.
You may not need
special preparation, especially if you have watery or bloody diarrhea.
Talk to your health professional about any concerns
you have regarding the need for this test, its risks, how it will be done, or
what the results may indicate. To help you understand the importance of this
test, fill out the
medical test information form(What is a PDF document?)
.
How It Is Done
You will usually lie on your left side
during the test. You may also be asked to kneel on the table with your bottom
raised in the air.
Once you are in position:
Your health professional will gently insert a
gloved finger into your anus to check for tenderness or blockage. For men, your
health professional will also check the condition of the
prostate gland.
The lubricated scope is
then inserted. The scope is moved slowly forward into the rectum and lower
colon. During a sigmoidoscopy, puffs of air sometimes are blown through the
scope to open the colon so that your health professional can see more
clearly.
Suction may be used to remove watery stool, enema liquid,
mucus, or blood through the scope.
Once your health professional
has moved the scope forward as far as possible, it is slowly withdrawn while
tissue is carefully inspected.
Your health professional may also
insert tiny instruments (forceps, loops, swabs) through the scope to collect
tissue samples (biopsy) or to remove growths. Tissue samples may be sent to a
laboratory for examination.
After the scope is removed, your anal area will be cleaned
with tissues. If you are having cramps, passing gas may help relieve
them.
The entire examination usually takes 5 to 15 minutes,
slightly longer if tissue samples are taken or if polyps are removed.
If you received a
sedative during the test, do not drive, operate
machinery, or sign legal documents for 24 hours after the test. Arrange to have
someone drive you home after the test.
After the test you may
resume your regular diet, unless your health professional gives you other
directions. Be sure to drink plenty of liquids to replace those you have lost
during the preparation for the sigmoidoscopy.
How It Feels
An anoscopy, proctoscopy, and
sigmoidoscopy examination can be embarrassing and uncomfortable. You may have
cramping, a feeling of pressure or bloating, or feel a brief, sharp pain when
the scope is moved forward or when air is blown into your colon.
The removal of tissue samples (biopsy) from the colon does not cause
discomfort. A
local anesthetic is used when a biopsy of the anal
area is done. Your anus may be sore for a few days.
You may have
mild gas pains and may need to pass some gas after the procedure. Walking may
help relieve the gas pains.
If a biopsy was done or a polyp
removed, you may have traces of blood in your stool for a few days.
Risks
There is very little risk of complications from
having an anoscopy, proctoscopy, or sigmoidoscopy.
There is a slight chance of piercing the colon
(perforation) or causing severe bleeding by damaging the wall of the colon.
However, these problems are rare.
There is also a slight chance of
a colon infection (very rare).
Call your health professional immediately if you
have:
Heavy rectal bleeding.
Severe
abdominal pain.
A fever.
Results
Anoscopy, proctoscopy, and sigmoidoscopy
tests allow your health professional to look at the inner lining of your
anus,
rectum, and the lower part of the
large intestine (colon).
Your health professional should be able
to discuss some of the findings with you immediately after the test. Lab
results (such as from a biopsy) may take several days.
Anoscopy, proctoscopy, and sigmoidoscopy
Normal:
The lining of the colon appears smooth
and pink, with numerous folds.
No abnormal growths, pouches,
bleeding, or inflammation is present.
Abnormal:
Some of the more common abnormal findings
include:
Hemorrhoids, which are the most common
cause of blood in the stool.
Redness and swelling of
the lining of the colon (colitis).
Your health professional will discuss
any significant abnormal results with you in relation to your symptoms and past
health.
What Affects the Test
Factors that can interfere with
your test or the accuracy of the results include:
Stool in the colon or rectum.
The
structure of the colon, such as a colon that has many turns.
A
barium enema done within a week before
sigmoidoscopy.
Rectal bleeding.
What To Think About
Follow-up tests, such as
colonoscopy, may be needed after sigmoidoscopy. A
colonoscopy may also be needed to examine the upper section of the colon if
growths were seen during sigmoidoscopy. For more information, see the medical
test
Colonoscopy.
In some cases, the
sigmoidoscope may be attached to a video monitor and a recording device that
lets your health professional see the inside the colon and record the
findings.
Most medical experts recommend colon cancer screening
beginning at age 50 for people who have an average risk and earlier for those
who have an increased risk for colon cancer, such as those with a family
history of colon cancer. Talk with your health professional about which colon
cancer screening test is best for you.
You may not be able to have
this test if you have peritonitis, diverticulitis, toxic megacolon, or if you
have had recent bowel surgery.
For more information on screening tests for colon cancer,
see:
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