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Sigmoidoscopy

Definition

Sigmoidoscopy is a procedure used to see inside the sigmoid colon and rectum.

Alternative Names

Flexible sigmoidoscopy; Sigmoidoscopy - flexible; Proctoscopy; Proctosigmoidoscopy; Rigid sigmoidoscopy

How the Test is Performed

During the test, you are positioned on your left side with your knees drawn up toward your chest. A gastroenterologist or surgeon will perform the test. First, the doctor does a digital rectal exam by gently inserting a gloved and lubricated finger into the rectum to check for blockage and to dilate (gently enlarge) the anus.

The sigmoidoscope has a small camera attached to a flexible tube. It is inserted through the anus and gently advanced. Air is introduced into the colon to open up the area and help the doctor see better. The air may cause the urge to have a bowel movement. Suction may be used to remove fluid or stool.

Because the health care provider gets a better view as the sigmoidoscope is pulled back out, a more careful examination is done while the scope is being pulled out.

Tissue samples may be taken with tiny biopsy forceps inserted through the scope. Polyps may be removed with electrocautery snares, and photographs may be taken.

Sigmoidoscopy using a rigid scope may be done to treat problems of the anus or rectum.

How to Prepare for the Test

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 health care provider may suggest that your child only drink clear liquids for 12 to 24 hours before the procedure.

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)
  • School age test or procedure preparation (6 to 12 years)
  • Adolescent test or procedure preparation (12 to 18 years)

How the Test Will Feel

There will be pressure when the scope or fingers are introduced into your rectum. You may feel the need to have a bowel movement during the procedure. There may be some bloating or cramping caused by the air or by stretching of the bowel by the sigmoidoscope. Biopsies cause no discomfort.

After the test, your body will remove the air that was introduced.

Children may be sedated for this procedure.

Why the Test is Performed

This test can help diagnose:

  • Abdominal pain
  • Diarrhea, constipation, or other changes in bowel habits
  • Blood, mucus, or pus in the stool
  • Colorectal polyps and cancer
  • Weight loss

This test can also be used to:

  • Confirm findings of another test or x-rays
  • Screen for colorectal cancer
  • Take a biopsy of a growth

Normal Results

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

Abnormal results can indicate:

  • Anal fissures
  • Anorectal abscess
  • Bowel obstruction
  • Cancer
  • Colorectal polyps
  • Diverticulosis (abnormal pouches on the lining of the intestines)
  • Hemorrhoids
  • Hirschsprung's disease
  • Inflammatory bowel disease
  • Inflammation or infection (proctitis)

Risks

There is a slight risk of bowel perforation (tearing a hole) and bleeding at the biopsy sites (the overall risk is less than 1 in 1,000).

References

Smith RA, Cokkinides V, Brooks D, Saslow D, Brawley OW. Cancer screening in the United States. 2010: a review of current American Cancer Society guidelines and issues in cancer screening. CA Cancer J Clin. 2010;60:99-119.

Weinberg DS. In the clinic: colorectal cancer screening. Ann Intern Med. 2008;148(3):ITC2-1-ITC2-16.

Kahn E, Daum F. Anatomy, histology, embryology, and developmental anomalies of the small and large intestine. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010:chap 96.