MedlinePlus Medical Encyclopedia: Sigmoidoscopy

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Sigmoidoscopy

Contents of this page:
Illustrations Alternative names Definition How the test is performed How to prepare for the test	How the test will feel Why the test is performed Normal Values What abnormal results mean What the risks are

Illustrations

Colonoscopy

Sigmoid colon cancer, X-ray

Anal biopsy

Alternative names Return to top

Proctoscopy; Proctosigmoidoscopy

Definition Return to top

Sigmoidoscopy is an internal examination of the distal large bowel (colon), using an instrument called a sigmoidoscope. The sigmoidoscope is a small camera attched to a flexible tube. It is inserted into the colon to examine the rectum, and the sigmoid and descending portions of the colon.

How the test is performed Return to top

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.

How to prepare for the test Return to top

You must sign an informed consent form. You will wear a hospital gown.

On the morning of the procedure, eat a light breakfast and then use a cleansing enema about 1 hour before the sigmoidoscopy.

Infants and children:
The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For general information regarding how you can prepare your child, see the following topics:

Infant test or procedure preparation (birth to 1 year)
Toddler test or procedure preparation (1 to 3 years)
Preschooler test or procedure preparation (3 to 6 years)
Schoolage test or procedure preparation (6 to 12 years)
Adolescent test or procedure preparation (12 to 18 years)

How the test will feel Return to top

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.

Why the test is performed Return to top

This test can help diagnose:

Inflammatory bowel disease
Bowel obstruction
Colon cancer
Colon polyps
Diverticulosis
Causes of diarrhea
Causes of abdominal pain

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

Normal Values Return to top

Normal findings show that the lining of the sigmoid colon, rectal mucosa, rectum, and anus appear normal in color, texture, and size.

What abnormal results mean Return to top

Abnormal results can indicate:

Hemorrhoids
Anal fissures
Anorectal abscess
Cancer
Colorectal polyps
Inflammation or infection (proctitis)
Bowel obstruction
Inflammatory bowel disease
Diverticulosis

What the risks are Return to top

There is slight risk of bowel perforation (hole) and bleeding at the biopsy sites (the overall risk is approximately 1 out of 1,000).

Update Date: 5/3/2004

Updated by: Christian Stone, M.D., Division of Gastroenterology, Washington University in St. Louis School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network.

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