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Information about Flexible sigmoidoscopy


What is flexible sigmoidoscopy?

Flexible sigmoidoscopy allows inspection of the lining of the rectum, anus and lower part of the colon/bowel. It uses a flexible tube with a video camera at the tip. Pictures from this camera are seen on a television by the endoscopist.The instrument is about 1 cm thick. This procedure usually takes about 20 minutes and can be done with or without sedation.

Why have a sigmoidoscopy?

Sigmoidoscopy is used to investigate symptoms you may be having such as change in bowel habit, rectal bleeding or to review a problem that has been found before such as polyps or Colitis. A sigmoidoscopy is a straightforward way of examining your lower bowel and therefore is often the first test that a doctor may request when you are experiencing bowel problems. It may however, be necessary to undertake further tests such as colonoscopy or CT scan following this procedure.

How do I prepare for a sigmoidoscopy?

You will be required to have a clear fluid diet the day before the procedure. Usually, an enema (a solution that is inserted into the rectum to clean the lower bowel) is the only preparation and it is given just before the procedure. Occasionally your doctor may decide not to use any preparation. It is unusual to require a full bowel clean-out prior to this procedure.

Should I continue my current medications?

Most medications can be continued as usual. Inform your doctor about medications that you are taking – particularly blood thinning medications such as warfarin, aspirin, persantin, plavix.

How is sigmoidoscopy performed?


Before the procedure begins a sedative is usually given, although it is not essential and some patients opt not to have sedation. If you do choose to have sedation you will not receive a full general anaesthetic so you will not be completely unconscious. You may be slightly aware of what is going on in the room but generally you won’t remember anything. The doctor and nursing staff will monitor your vital signs during the procedure and will try to make you as comfortable as possible.

You will lie on your left side while your doctor insertrs the endoscope through the rectum and advances it through the colon. You might experience a feeling of pressure, bloating or cramping during the procedure when the endoscopist introduces air in the bowel via the endoscope. This is normal and air can usually be relieved by passing wind which you should not feel embarrassed about.

You may be asked to change position during the procedure e.g. roll onto your back to make the procedure easier.

Removal of polyps and biopsies

Polyps are growths from the lining of the colon, and can vary in size and type. Some are perfectly innocent but others can slowly develop into cancer if they are not removed. If your doctor finds polyps, he or she might take a biopsy of them, remove them then and there, or might organise a colonoscopy in order to examine the entire colon.

Biopsies are used to identify many conditions, so your doctor might perform one even if he or she doesn’t suspect cancer.

Are there any risks or side effects?

Although complications can occur, they are rare and will be discussed with you prior to the procedure taking place.

  • Having a sigmoidoscopy carries a small risk of making a hole in the bowel wall (perforation) this occurs once in every 1000 examinations. Perforations usually need to be repaired with an operation.
  • If a polyp is removed then the risk of perforation, although still rare increases slightly to 1 in 500 occasions.
  • Bleeding from the back passage can occur, especially if biopsies are taken or polyps removed. Bleeding usually stops without any treatment, although occasionally treatment is needed to stop this.
  • Using sedation can affect your breathing. Your breathing is monitored by staff during the procedure. The endoscopist may give you minimal sedation if it is felt that you are at high risk of breathing difficulties during the procedure.
  • Despite sedation some patients experience abdominal discomfort or pain due to the air that is put into the bowel via the endoscope or due to the scope negotiating the natural bends in the bowel. This should decrease when the procedure has ended and will be helped by passing wind.

What happens after flexible sigmoidoscopy?

After the procedure you will remain in the recovery area until the sedation wears off. If you have not had sedation you will be able to go home straight away.

You will usually be given something light to eat or drink once you are awake. You should expect to be with us for approximately 3- 4 hours in total.

Your doctor will explain the results to you when the procedure is done. The result of the biopsies or samples can take 1-2 weeks to be processed so your results can be discussed with you by your GP or specialist.

You might feel bloating or some mild cramping because of the air that was passed into the colon during the examination. This will disappear quickly when you pass gas.

Who can I contact if I have any questions?

You will be given an opportunity to ask questions prior to your procedure when consent is obtained by your doctor.

If you have any problem understanding or reading any of this information, please contact the Endoscopy Unit staff on 570 9191.