What is a sigmoidoscopy?

A sigmoidoscopy is a procedure that is performed to examine the lower part of the colon.

Who should have this procedure?

This procedure may be done if a doctor suspects or knows a person has:

  • Colorectal polyps (small growths on the walls of the bowel or colon).
  • A tumor in the colon or bowel.
  • Bleeding from the bowels (known as gastrointestinal bleeding).
  • Certain types of colitis or inflammation of the colon.
  • A twist in the lower bowel that is blocking the bowel or causing pain.
  • This procedure is also done to screen for colon cancer in healthy persons starting at age 50. It may be done before age 50 if a person has risk factors, such as family history of colon caner.

How is the procedure performed?

Before the procedure, the bowel must be cleaned out to allow a good view. If too much stool is in the lower colon, the doctor will be unable to see the inside walls of the bowel. A person will be asked to stop eating at least 8 hours before the procedure. Laxatives and an enema are often given before the procedure to help clear the bowel. This preparation is very important. If the instructions are not followed, the procedure may have to be repeated.

The procedure takes about 15 to 20 minutes and is performed in the office. The person may be given a medication to help him or her relax. Before the procedure, the person changes into a hospital gown. He or she then lies on an exam table in a special position. During the exam, a sigmoidoscope is used to allow the doctor to see the inside of the bowel. Sigmoendoscopy uses a special tube with a light and camera on to the end of it.

The anus is lubricated and the endoscope is passed through it into the rectum. This is somewhat uncomfortable and may cause an urge to defecate. Puffs of air through the tube are used to help open up the colon. This makes it much easier to get a good view of the tissues.

During the procedure, the doctor can also:

  • Remove any colorectal polyps.
  • Take a sample of tissue to be examined in a lab.
  • Straighten out a loop of twisted colon.

What happens right after the procedure?

Most people handle the procedure very well and have no problems. It can be uncomfortable, but it is not usually painful. However, after the procedure, a person may notice the following:

  • Gas pains.
  • Slight rectal bleeding, especially if tissue samples or polyps were removed.
  • Drowsiness if anesthesia was used. In this case the person must be driven home by someone else.

The doctor will usually talk to the person right after the procedure about what he or she found. If samples of tissue or polyps were removed, it may take several days for the results to come back. These results will be discussed at a follow-up visit.

What happens later at home?

A person should call the healthcare provider if there are any signs of problems after the procedure, such as:

  • Increasing abdominal distress.
  • Fever and chills.
  • Frequent bloody bowel movements.
  • Severe bloating and an inability to pass gas.

There is a small risk of bleeding or infection. In rare cases, a small hole may be made in the bowel. This may need to be treated with antibiotics or sometimes surgery. An allergic reaction to medications given for relaxation may also rarely occur.