Flexible Sigmoidoscopy
An internal exam of the lower part of the large intestine using a short, flexible lighted tube.
A sigmoidoscopy is an internal exam of the lower part of the large intestine (colon) using a short, thin, flexible lighted tube. The tube, called a flexible sigmoidoscope, has a tiny camera at the tip allowing the doctor to view the inside of the rectum and the sigmoid colon — about the last two feet of the large intestine. A small biopsy instrument to remove tissue samples to be checked under a microscope for signs of disease can be performed during the examination.
A flexible sigmoidoscopy can help your doctor determine the cause of abdominal pain, rectal bleeding, changes in bowel habits, chronic diarrhea and other intestinal problems. Your doctor may be able to diagnose the cause of diarrhea, bowel obstruction, diverticulosis, inflammatory bowel disease, anal fissures and hemorrhoids, as well as find colon polyps in the lower part of the colon.
Note: Flexible sigmoidoscopy does not allow the doctor to see the entire colon. Therefore, any cancers or polyps farther into the colon cannot be detected. A colonoscopy allows the doctor to examine the entire colon.
Preparing for Flexible Sigmoidoscopy
The lower colon and rectum must be completely empty for a flexible sigmoidoscopy to be thorough and safe. Some doctors recommend a combination of a laxative and a small enema before the test. Some doctors may advise the patient to drink only clear liquids for 12 to 24 hours before the procedure. The night before, or even immediately before the flexible sigmoidoscopy, the patient may be given an enema.
What Happens During the Procedure?
During the test the patient is positioned on the left side with knees drawn up toward the chest. First, the doctor will do a digital rectal exam. Next, the sigmoidoscope is inserted into the rectum, and the patient will feel some pressure. Air is introduced through the scope to expand the colon and help the doctor see adequately. As the scope is slowly removed, the lining of the bowel is carefully examined.
What Happens After the Procedure?
This procedure takes about 15 minutes. After the exam, you may have mild abdominal discomfort. You may feel bloated or pass gas for a few hours as you clear the air from your colon. You will be able to return to your normal diet and routine after the procedure. You may have a small amount of blood in your stool with your first bowel movement after the procedure — this is normal.
Possible Outcomes
The exam is considered negative if the doctor does not find any abnormalities. A positive exam might identify polyps or abnormal tissue in the colon. Depending on the findings, you may need additional testing, such as a colonoscopy, so that the entire colon can be examined.