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What is a flexible sigmoidoscopy?
A flexible sigmoidoscopy is an investigation using a flexible telescopic tube (colonoscope) to look at the lining of the lower part of the large bowel (colon). A tube called a colonoscope, is inserted at the anus (back passage) and moved around the lower part of the colon (bowel).The colonoscope has a camera in its tip which sends pictures of the inside of your colon to a video screen.
Why do I need a flexible sigmoidoscopy?
Your GP or hospital specialist has recommended you have this test to investigate the cause of your symptoms. There are many reasons for this investigation including: bleeding from your anus, pain in the lower abdomen, persistent diarrhoea and changes to your bowel habits. Likewise, if you suffer from inflammatory bowel disease or have a family history of bowel cancer, you may need to be monitored.
What are the benefits of having a flexible sigmoidoscopy?
If there is any abnormality in the bowel then it should be possible to see it during the procedure which is relatively quick. It allows the doctor to take samples (biopsies) of tissue so they can be examined under a microscope. The lining of the bowel is insensitive to pain so you should not feel anything when the samples are removed.
A normal test result can reassure you that all is well. A flexible sigmoidoscopy can also help us reach a diagnosis (sometimes by taking biopsies) to make sure you are on the best treatment. If you have polyps, we can remove them during the procedure
Is there an alternative to having a flexible sigmoidoscopy?
There is an alternative called CT colonography. This is a less invasive test which uses special x-ray equipment and computers to obtain an interior view of the colon. However, it is a strictly diagnostic procedure, that still requires bowel prep to be taken, but which does not allow tissue to be sampled or remove polyps (growths on your bowel lining) at the same time, both of which help with your diagnosis.
If we find an abnormality in the lower part of the large bowel during a CT colonography or the rigid sigmoidoscopy, you would then need to have a flexible sigmoidoscopy to examine or treat it.
Are there any risks involved?
A flexible sigmoidoscopy is an extremely safe procedure is performed by a specially trained clinician who takes every care to reduce any risks and serious complications are very rare. But they can include:
- Bleeding: It is common to pass small amount of blood from your anus if a biopsy or a polyp has been removed. This should only happen up to 12-24 hours after the procedure. So do not worry if you open your bowels after the test and notice some blood.
- Perforation: We take every care to avoid perforation; but if it happens your abdomen may become painful and bloated. You may need medicine, need to stay in the hospital, have more tests such as a CT scan or, in extremely rare cases, you may need surgery to repair the hole. The risk of making a perforation (tear) during this test is less than 1 in 5,000.
- Failure to complete: Occasionally, the procedure may need to be abandoned or may be incomplete. For example, if you find the procedure too uncomfortable or if an enema or bowel prep medication did not empty the lower part of your bowel completely. In this case, the procedure may need to be repeated or we may suggest an alternative procedure.
Will I need sedation or painkiller?
Most individuals will tolerate the procedure well without sedation as the procedure does not take very long. On the day you will be offered Entonox® for pain relief which can improve your comfort so that the endoscopist can perform the procedure successfully. Sedation is also offered and will be assessed on and individual basis.
Entonox® (gas and air)
Entonox is a very quick acting painkiller which you inhale (breathe in). It will make you feel relaxed and sleepy whilst relieving your pain. The effect of Entonox wears off very rapidly allowing you to fully function within a short time, although the effects of the procedure itself may prevent you being active. You should not drive or operate any machinery for at least 30 minutes after Entonox and not until you feel it is safe to do so.
Please read the attached advice sheet on Entonox®. If you have not received this, please call the booking office: see pages 10-11 for contact details.
Will I have to stay in hospital?
You will usually have the sigmoidoscopy as a day patient, involving a stay of 2 - 4 hours.
How long does the test take?
It usually takes 5 – 10 minutes. It may take longer depending on what needs to be done.
What preparation do I need for the examination?
We need to get a clear view, so your lower bowel must be clean. To get good views, you may need take oral medication for bowel preparation or an enema to clear out the bowel. A separate bowel preparation information leaflet will be sent to you if you are having an oral medication or an enema to provide you with detailed instructions.
If you have been advised to have a phosphate enema, you do not have to stop eating and drinking.
If you have been advised to take oral bowel preparation, please follow the low fibre diet below.
Two days before your examination
Eat only the following foods:
white fish, chicken, cheese, white bread, eggs, butter or margarine, plain yoghurt, honey (but not jam or marmalade), rich tea biscuits, potato (without the skin), yellow jelly (not red), ice cream, sorbets (not red). Have plenty to drink.
Do not eat high fibre foods, red meat, pink fish, fruit, vegetables, mushrooms, salad, wholemeal bread, cereals or pulses in any form.
Do I need to stop taking my medication?
You can continue to take your routine medication.
If you take blood thinning medication, you may need to stop taking them for a short time. If you have not been advised whether you need to stop or continue to take them, please contact us (see pages 10-11 for contact details).
If you have been advised to stop your food or drink and you are diabetic, please read our advice sheet. If you have not received this, please call the booking office (see pages 10-11 for contact details) and we will send you a copy.
If you take iron tablets, if possible, stop taking them at least one week (preferably up to two weeks) before the flexible sigmoidoscopy.
If you are taking any other medications, in general you can take these as usual, unless your doctor has advised you otherwise.
Informed Consent
Prior to the procedure, you will be required to sign a consent. Before signing it, the healthcare professional will discuss with you what the procedure is likely to involve; the intended benefits; alternative investigations; significant, unavoidable or frequently occurring risks; and any extra procedures which may become necessary. All of the information which will be discussed with you is included in this leaflet. We want to involve you in decisions about your care and treatment. If you are unsure about any aspect of the treatment proposed, please do not hesitate to speak with a member of staff.
What happens when I arrive for my test?
Please note that your appointment time is the time that you should arrive in the department. It is not the time of your actual procedure. We recommend that you plan to be with us for the whole morning or afternoon, depending on your time slot.
When you arrive, a nurse will complete your assessment with you and ask you about your arrangements for getting home. The nurse/health professional will explain the procedure and if you choose to have sedation or Entonox and obtain your consent.
The nurse will check your temperature, blood pressure, pulse, respiration rate and your oxygen levels. If applicable, the nurse will check your INR and blood sugar levels. We will ask you to change into a hospital gown, remove your underwear and put on a pair of dignity shorts.
What happens before the test?
A nurse will take you into the endoscopy room and make you comfortable on a examination trolley. They will go through a safety checklist prior to the procedure starting and the endoscopist will speak to you.
The nurse will monitor your blood pressure, pulse, respiration rate and your oxygen levels during the test. The nurse will ask you to lie down on your left side. The nurse or endoscopist will reconfirm your choice of pain relief if requested. If you are having a sedative, oxygen will be given through an oxygen tubing placed in your nostril.
What happens during the test?
A nurse will be with you at all times during your procedure to reassure you and talk you through what is happening.
The endoscopist will gently place the colonoscope into your back passage/anus and move it along the lower part of your bowel. They may ask you to change position to:
- make you more comfortable.
- make it easier to pass the colonoscope around your bowel.
- and / or make sure they can see as much of the inside lining of your bowel as possible.
During the procedure the endoscopist will use medical gas/ water to inflate the bowel to visualise the colon. You may feel ‘wind’ or cramps during the procedure and perhaps the occasional ‘twinge’ as the colonoscope is pushed around bends. It should not be painful. If it is, please tell the endoscopist.
The endoscopist can take biopsies or remove polyps during the test, by passing thin instruments through the colonoscope. This does not hurt and you may not feel it happening at all. During the test medical photographs are taken for the report.
What happens after the test?
You may need to rest in the unit for up to half an hour afterwards You may feel a little bloated with wind pains but these usually disappear quickly. You may resume eating as normal.
In rare instances where you do not feel well, we will keep you in recovery for longer for observation until it is safe to discharge you home.
Will I get the results straight away?
When you have recovered, a healthcare professional will explain the results and will give you the endoscopy report before you leave the department. We will also send a copy of the report to your GP or the hospital specialist. If a biopsy has been taken or a polyp removed, you will be told when and where you can get the results.
What happens when I go home?
- You may feel a little bloated and have some mild cramps due to gas that was put into your bowel during the procedure; this will soon settle.
- After effects are rare, but you may notice some bleeding if a biopsy has been taken or a polyp removed.
- You can eat and drink as normal and continue to take your regular medication unless advised otherwise.
Care provided by trainees.
Our department supports clinical training and so there may be a trainee nurse or doctor assigned to the procedure list. We will make the investigation as comfortable as possible for you.
If you do not wish to have your care or procedure undertaken by a trainee, please advise the staff. Neither your treatment nor timings will be affected by your decision.
What should I bring with me to hospital?
- a list of medications, including allergies to medications, food or substances
- please bring your essential medications such as insulin, Parkinsons medication, epilepsy medications, inhalers, CPAP machine, etc.
Please do not bring any valuables with you. The hospital cannot accept responsibility for the loss or damage to personal property during your stay in endoscopy.
Please make sure you have the contact details of the person who will take you home.
If you need an interpreter please contact us as soon as possible so we can make the necessary arrangements.
Who can I contact with queries and concerns?
Frimley Park Hospital
For medication queries, please contact the nursing team between 8am – 1pm Monday to Friday:
Endoscopy Unit, Frimley Park Hospital: 0300 613 6045
For appointment queries or to request information leaflets, including diabetic leaflets, contact the admin team:
Endoscopy booking for Frimley Park Hospital: 0300 613 6647
Frimley - fhft.endoscopyadminfph@
Heatherwood Hospital
For medication queries, please contact the nursing team between 9am - 4pm Monday to Friday:
Endoscopy Unit, Heatherwood Hospital: 0300 614 4020
For appointment queries or request information leaflets, including diabetic leaflets, contact the admin team:
Endoscopy booking for Heatherwood Hospital: 0300 614 4009 or 0300 614 4008
Wexham Park Hospital
For medication queries please contact the nursing team between 9am - 4pm Monday to Friday:
Lady Sobell Unit, Wexham Park Hospital: 0300 615 4163
Endoscopy Suite, Wexham Park Hospital: 0300 615 9448
For appointment queries or request information leaflets, including diabetic leaflets, contact the admin team:
Endoscopy booking for Wexham Park Hospital: 0300 615 4157
Wexham - fhft.endoscopyquerieshwph@
Contact us
If you have any queries relating to this information, please contact the Endoscopy service.
About this information
Service:
Endoscopy
Reference:
H/080
Approval date:
10 January 2025
Review date:
10 January 2028
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Important note
This page provides general information only. It is developed by clinical staff and is reviewed regularly every 3 years for accuracy. For personal advice about your health, or if you have any concerns, please speak to your doctor.