Having a Flexible Sigmoidoscopy (Inpatients)

What is a Flexi-Sigmoidoscopy?

Flexi-Sigmoidoscopy diagram

This is an examination of the left side (lower part) of the large bowel using a flexible colonoscope. The examination takes about 10-15 minutes.

You will have seen your GP or a Consultant with concerns about your bowels, for example bleeding or a change in bowel habit that does not seem to be returning back to normal. The GP or Consultant would have then referred you for this examination to find the cause of your symptoms.

If the Endoscopist thinks the bowel lining does not look normal they will use this opportunity to take tiny samples of tissue called biopsies. Sometimes small benign growths, called polyps, are found at Sigmoidoscopy. Polyps are generally removed there and then. Some polyps, if left for years, have the potential to change into cancers.

The benefits of a Flexible Sigmoidoscopy are that it is quick and that it examines the part of the bowel where most bowel problems occur.

Why do I need to have a Flexible Sigmoidoscopy?

You have been advised to have this investigation to try and find the cause of your symptoms, help with treatment and if necessary, to decide on further investigations.

There are many reasons for this investigation including:

  • Rectal Bleeding
  • Altered Bowel Habit
  • Abnormal Findings on previous scans
  • Assessment of Inflammatory Bowel Disease (IBD)
  • Polyp Surveillance
  • Banding of Haemorrhoids

Your procedure

Specialist doctors or nurses perform the majority of these procedures, however Bedford Hospital has commitments to train both doctors and nurses in all aspects of endoscopy and care and your test may involve Doctors or nurses training in the performance of sigmoidoscopy. Their training is provided through specialist courses and supervised by experienced consultants. If you have any queries about this please do speak to a member of the team.

The preparation

To allow a clear view, the colon must be completely empty of waste material. It is important to take the entire laxative prescribed and also considerably increase your intake of clear fluids on the day before examination, which will help clean the bowel.

Occasionally an enema may need to be given in the ward before the procedure.

During the test

A flexible sigmoidoscopy usually takes 10-15 minutes, although it may take longer if it’s being used to treat a condition.

You will be taken into the examination room, where the endoscopist and the nurses will introduce themselves and you will have the opportunity to ask any final questions.

You will be asked safety questions about you and your health prior to the procedure.

In the examination room you will be made comfortable on a couch, resting on your left side, with your knees slightly bent. A nurse will stay with you throughout the test. A small device will be attached to your finger or thumb in order to record your pulse rate and monitor your general condition during the examination and they will insert a tiny sponge into a nostril to administer oxygen, if required.

The Endoscopist will examine your bottom first with a finger, this is to feel the first few centimetres of the bowel.

When the tube has been gently inserted through the anus into the large bowel, air will be passed through it to give a clearer view of the lining. This may give you some wind-like pains but they will not last long. You may get the sensation of wanting to go to the toilet, but as the bowel is empty, there is no danger of this happening. You may pass some wind but, although this is embarrassing, remember the staff do understand what is causing it. If you are finding you have discomfort you will be offered Entonox (Gas & Air) to help relieve the pain. It usually takes up to thirty minutes for the colon to be examined, but the test sometimes lasts longer. When the examination is finished, the tube is removed safely.

Sometimes the doctor takes a biopsy – a sample of the lining for examination in the laboratory. A small piece of tissue is removed painlessly through the colonoscope, using tiny forceps. It is also possible to remove polyps during the sigmoidoscopy. Polyps are abnormal projections of tissue, which the doctor will want to examine in detail.

After the test, how soon will I go back to the ward?

After the test, you will be transferred to the recovery area where you will be monitored until the ward staff comes to collect you, if you. You may feel a little bloated with wind pains but these usually settle quite quickly. The nurse or doctor in the ward can go through your report and the results of your procedure.


There are some risks associated with this procedure, however serious complications during sigmoidoscopy are very rare. There is a small risk that during the examination a small tear can be made through the bowel wall (perforation). If this occurs you may begin to feel unwell, become nauseous and your tummy may feel hard, swollen and painful. This may lead to a hospital admission and sometimes an operation.

Another risk is bleeding. Care is taken to ensure there is no bleeding after the removal of polyps but as the bowel contracts when the bowels are opened this sometimes causes the area to bleed. You may experience spotting on the toilet paper, this usually subsides. If it continues report this to the ward nurses.

The risk of either of the above is about 1: 10000.

Lifestyle changes

If you smoke, stopping smoking will improve your long-term health. Try to maintain a healthy weight. You have a higher risk of developing complications if you are overweight. Regular exercise should improve your long-term health. Before you start exercising, ask the healthcare team or your GP for advice.


A flexible sigmoidoscopy is usually a safe and effective way of finding out if there is a problem with your large bowel. However, complications can happen. You need to know about them to help you make an informed decision about the procedure. Knowing about them will also help to detect and treat any problems early.