Sigmoidoscopy (Anoscopy, Proctoscopy)

Why It Is Done

These tests are done to:

• Detect problems or diseases of the anus (anoscopy), rectum (proctoscopy), or lower large intestine, also called the sigmoid colon, (sigmoidoscopy). These tests are often done to look for causes for symptoms such as unexplained bleeding from the rectum, long-lasting diarrhea or constipation, blood or pus in the stool, or lower abdominal pain.
• Remove hemorrhoids.
• Check for and remove polyps.
• Monitor the treatment of inflammatory bowel disease.
• Screen for colon cancer.

How To Prepare

Anoscopy

Usually, no preparation is needed for an anoscopy.

Proctoscopy and sigmoidoscopy

Test preparation for a proctoscopy and sigmoidoscopy may be similar. Before the test:

The preparation for these tests usually involves a thorough cleaning of the lower colon. It must be completely clear of stool (feces). Even a small amount of stool can affect the accuracy of the test.

• You may be told to follow a liquid diet for 1 to 2 days before the test.
• You may be told to not eat for up to 12 hours before the test.
• You may need to have two enemas before the test.
• You may not need special preparation, especially if you have watery or bloody diarrhea.

How It Is Done

You will most likely 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.

When you are in position:

• Your doctor will gently insert a gloved finger into your anus. If you have a prostate, your doctor will also check the condition of the prostate gland.
• The lubricated scope is then inserted. The scope is moved slowly forward into the anus (anoscopy), the rectum (proctoscopy), or lower large intestine, also called the sigmoid colon (sigmoidoscopy).
• During a sigmoidoscopy, puffs of air sometimes are blown through the scope to open the colon so that your doctor can see more clearly.
• Suction may be used to remove watery stool, enema liquid, mucus, or blood through the scope.
• After your doctor has moved the scope forward, it is slowly withdrawn while tissue is carefully inspected.
• Your doctor may also insert tiny tools (forceps, loops, swabs) through the scope to collect tissue samples (biopsy) or to remove growths. Tissue samples may be sent to a lab to be checked.

After the test

After the scope is removed, your anal area will be cleaned with tissues. If you are having cramps, passing gas may help relieve them.

How long the test takes

The entire examination usually takes 5 to 15 minutes. It may take slightly longer if tissue samples are taken or if polyps are removed.

How It Feels

These tests can be uncomfortable. You may have cramping or a feeling of pressure or bloating. You may feel a brief, sharp pain when the scope is moved forward or when air is blown into your colon. As the scope is moved up the colon, you may feel the need to have a bowel movement and pass gas. If you have pain, tell your doctor.

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.

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. But these problems are rare.
• There is also a slight chance of a colon infection (very rare).

Results

Your doctor should be able to discuss some of the findings with you right after the test. Lab results (such as from a biopsy) may take several days.

Your doctor will discuss any significant abnormal results with you in relation to your symptoms and past health.