St Mark's HospitalLondon North West Healthcare

Flexible Sigmoidoscopy

What is Flexible Sigmoidoscopy?

A Flexible Sigmoidoscopy is most commonly used to look for bleeding or non-cancerous growths, called polyps, in the colon and is one of the main screening tests for colorectal cancer. It is a common outpatient procedure in which the inside of the lower part of the large intestine (also called the sigmoid or left colon) is examined with a flexible video endoscope.

What else may be done during the procedure?

During the sigmoidoscopy a biopsy (a sample of the lining of the bowel for closer examination under the microscope) may be taken using tiny biopsy forceps passed through the endoscope. This is a painless procedure.

It is also possible to remove small polyps during sigmoidoscopy. Polyps are abnormal projections or growths of tissue, rather like a wart, and certain types of bowel polyps may be at risk of developing into cancer if left. If polyps are found the endoscopist may decide to remove them via polypectomy during the procedure, again this is a painless procedure. It may then be necessary to return for a colonoscopy to examine the whole colon and treat any large or difficult to remove polyps.

Bowel preparation

When you come to the department, a member of staff will explain the test to you and will usually ask you to sign a consent form. This is to ensure that you understand the test and its implications. Please tell the doctor of nurse if you have had any allergies or bad reactions to drugs or other tests. They will also want to know about any previous endoscopy you have had, or any other medical conditions which you may suffer from and details of medication which you may be taking. If you have any worries or questions at this stage don't be afraid to ask, the staff will want you to be as relaxed as possible for the test and will not mind answering your queries.

Your rectum and lower bowels must be empty for the exam to be accurate and complete, but usually there are no diet or fluid restrictions before this procedure. To prepare the bowel for the procedure, an enema will be administered shortly after you arrive in the department by one of the nursing staff. Try to hold the enema for at least five minutes before releasing it. On occasion, you may have to drink an oral laxative as well.

In most cases, sedatives and/or anaesthesia are not necessary. Therefore, you can drive yourself home after the procedure. The patient information sheets can also be downloaded here.

During the procedure

You will be placed in a comfortable position on your left side and the endoscopist will then pass the sigmoidoscope into the rectum, and advance it through the lower colon. You may experience some abdominal cramping and pressure from the air which is introduced into your colon, this is normal and will pass quickly. You may also be asked to change position during the examination, and will be assisted by a nurse. The procedure usually involves minimal discomfort and takes anywhere from 5-15 minutes.

After the procedure

You will usually be able to leave the endoscopy department very soon after the test, once you are changed and the results of the procedure have been explained. 

When will I know the results?

In most cases a member of staff will be able to tell you the results of the test and you will be given a copy of the endoscopy report to take home. However, if a biopsy sample or polyp was removed for microscopic examination these results may take up to two weeks to process.

What to expect after a Flexible Sigmoidoscopy?

A member of staff will discuss the results of the sigmoidoscopy with you and you will usually receive a copy of the endoscopy report to take home. You may continue to experience mild cramps or gas, but that passes quickly and you can resume normal activities and diet.

If you have had any biopsies taken or polyps removed, you may notice small traces of blood coming from your back passage. If this was the case you will have been told by the doctor or nurse caring for you before discharge. If the bleeding persists, becomes more severe or the abdominal pain becomes worse, you should contact either the Endoscopy Unit, your GP or attend you nearest Accident and Emergency Department (taking a copy of your endoscopy report).

You may resume normal medications immediately after your flexible sigmoidoscopy, but if a polyp was removed we may advise against taking certain blood-thinning or anti-inflammatory drugs for a defined period. Please ask if you are not sure that a medication will be safe. You may take stool softeners and bran but do not take strong laxatives.

Things to report to your doctor:

  • Severe pain or vomiting
  • Passage or vomiting of blood
  • Temperature greater than 38 degrees

If you have any worries please do not hesitate to contact the Endoscopy Department, your own GP or go to your nearest Accident & Emergency Department (taking a copy of your endoscopy report).