Flexible sigmoidoscopy

Published by Bupa’s Health Information Team, October 2011.

This factsheet is for people who are having a flexible sigmoidoscopy or who would like information about it.

A flexible sigmoidoscopy is a procedure that is used to look inside the rectum (back passage) and lower part of the large bowel.

You will meet the doctor carrying out your procedure to discuss your care. It may differ from what is described here as it will be designed to meet your individual needs.

About flexible sigmoidoscopy

A flexible sigmoidoscopy allows your doctor to look inside your rectum and lower part of your bowel using a narrow, flexible, tube-like telescopic camera called a sigmoidoscope.

A flexible sigmoidoscopy is usually performed in an endoscopy clinic and you don't usually need to have an anaesthetic or any sedation. A sedative relieves anxiety and helps you to relax.

Your doctor may remove polyps or take a biopsy during the procedure. A biopsy is a small sample of tissue. This will be sent to a laboratory for testing to determine the type of cells and if these are benign (not cancerous) or cancerous.

Flexible sigmoidoscopy is very effective at detecting bowel cancer and is currently being introduced into the NHS Bowel Cancer Screening Programme as a one-off test for all men and women aged 55 to 60. It aims to detect bowel cancer early before you develop any symptoms. After the age of 60, the screening programme offers a faecal occult blood (FOB) test every two years. Bowel cancers can sometimes bleed and the FOB test can detect tiny amounts of blood, which you can’t normally see in faeces.

What are the alternatives to flexible sigmoidoscopy?

Depending on your symptoms and circumstances, it may be possible to diagnose your bowel condition using a different test. The alternatives are listed below. 

• Barium enema. This involves placing a fluid containing barium (a substance which shows up on X-rays) into your bowel via your rectum. X-ray images of your abdomen (tummy) then show the inside of your bowel more clearly.
• Virtual colonoscopy and CT colonography. This involves having a CT scan of your abdomen. The CT scan uses X-rays to produce three-dimensional images of your lower bowel (colon) and rectum.
• FOB test. This looks for blood in a sample of your faeces (stool sample).
• Colonoscopy. This is like a flexible sigmoidoscopy but looks at the whole of your large bowel.
• Rigid sigmoidoscopy. This allows your doctor to look at the lower 25 to 30cm of your bowel. Unlike flexible sigmoidoscopy, you won’t need to prepare your bowel for the procedure. It usually takes less than 10 minutes to carry out.
• Proctoscopy. This is an examination of the anal canal using a tube that is about 10cm long. It allows polyps and piles (haemorrhoids) to be seen and treated.

You may need to have a combination of tests to get a diagnosis. Your doctor will explain your options to you.

Preparing for a flexible sigmoidoscopy

Your doctor will explain how to prepare for your examination.

If you normally take iron tablets, codeine phosphate or medicines that bulk out your faeces, such as ispaghula husk, you will probably be asked to stop taking them for up to two weeks before the procedure. If you usually take other medicines, continue to take these as usual unless your doctor specifically tells you not to. If you're unsure about any medicine you're taking, ask your doctor for advice.

Your bowel will need to be completely empty for your doctor to be able to see it clearly. You may be given a strong laxative to take to help empty your bowel, or you may be given an enema (a liquid injected into your rectum) to use before you come into hospital. You will be given instructions on how and when to do this. You can eat and drink as usual until you have the enema and after that drink clear fluids only. If you have difficulty giving yourself an enema at home, you can have it just before the procedure.

Your doctor will discuss with you what will happen before, during and after your procedure, and any pain you might have. This is your opportunity to understand what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the procedure. This will help you to be informed, so you can give your consent for the procedure to go ahead, which you may be asked to do by signing a consent form.

What happens during a flexible sigmoidoscopy

You may be asked to put on a gown before your procedure.

A flexible sigmoidoscopy usually takes between 10 and 20 minutes. It may feel uncomfortable, but shouldn't be painful.

Sedation isn’t usually necessary during a flexible sigmoidoscopy but if you do have a sedative, it will be given to you as an injection into a vein in your hand or arm.

While you're resting on your side, your doctor will gently examine your rectum by inserting a finger (he or she will wear gloves). Your doctor will then carefully insert the sigmoidoscope into your rectum. He or she will use lubricating jelly to make this as comfortable as possible.

Your doctor will pump air through the sigmoidoscope into your lower bowel to make it expand. This will make it easier to see your bowel wall. You may get stomach cramps and feel an urge to go to the toilet or pass wind.

A camera lens at the end of the sigmoidoscope will send pictures from the inside of your bowel to a monitor. Your doctor will look at these images and, if necessary, take a biopsy and/or remove any polyps you have. This is done using special instruments that are passed inside the sigmoidoscope. It shouldn't cause you any pain.

You will probably be in hospital for between one and two hours.

What to expect afterwards

If you haven't had a sedative, you will usually be able to go home when you feel ready.

If you have had a sedative, you may need to stay a little longer and a nurse will monitor your blood pressure and pulse while you recover. You will need to arrange for someone to drive you home. Sedation temporarily affects your co-ordination and reasoning skills, so you must not drive, drink alcohol, operate machinery or sign legal documents for 24 hours afterwards. If you’re in any doubt about driving, contact your motor insurer so that you’re aware of their recommendations, and always follow your doctor’s advice.

Before you leave, your doctor or nurse may explain what he or she saw inside your bowel during the procedure. If you have had a biopsy or polyps removed, the results will be ready several days later and will usually be sent in a report to the doctor who requested your test.

Once you get home, it's sensible to take it easy for the rest of the day. You should feel able to resume your normal activities the following day.

What are the risks?

As with every procedure, there are some risks associated with a flexible sigmoidoscopy. We have not included the chance of these happening as they are specific to you and differ for every person. Ask your doctor to explain how these risks apply to you.

Side-effects

Side-effects are the unwanted but mostly temporary effects you may get after having the procedure. After a flexible sigmoidoscopy, you may have some mild pain and discomfort. You may also have a swollen abdomen because of the air that was pumped into your bowel. This usually gets better after an hour or so.

Complications

Complications are when problems occur during or after the procedure. Possible complications of a flexible sigmoidoscopy are listed below.

• A tear in your bowel. Although it's rare, this can happen during the procedure, particularly if your doctor has removed a polyp or taken a biopsy - it can lead to an infection. If you develop a high temperature, severe pain or a swollen abdomen, contact the hospital or your GP urgently.
• Bleeding. This is most likely if you have had polyps removed or a biopsy taken. This usually stops on its own within a few days. If you have any heavy bleeding or see blood in your faeces, contact your hospital or your GP.
• Sedatives can occasionally cause problems with your breathing, blood pressure and heart rate. You will be monitored while you’re under sedation and during your recovery.

It's possible that your procedure might not be completed successfully and may need to be done again.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.