What is a flexible sigmoidoscopy?
A flexible sigmoidoscopy is an endoscopic procedure in which your lower colon is examined. It is done using a colonoscope but does not investigate as much of the colon as a full colonoscopy.
What happens during a flexible sigmoidoscopy?
An endoscopist guides the long, thin, flexible tube containing a tiny video camera from the anus, through the rectum and inwards up to half way around the colon. The exact distance the tube is inserted depends on why the procedure is being done.
Images from the camera are shown on a screen, allowing your consultant to see the inside of the bowel. The colonoscope can be used to take a biopsy if required. The test can be slightly uncomfortable, but not painful.
How long does a flexible sigmoidoscopy take?
Usually about 15 minutes.
Why might you need a flexible sigmoidoscopy?
A flexible sigmoidoscopy can investigate a range of unexplained problems:
- Rectal bleeding
- A change in bowel habits
- Chronic diarrhoea or constipation
- Iron deficiency anaemia
- Weight loss
- Abdominal pain
- A suspected polyp.
It can also be used to assess or monitor conditions such as inflammatory bowel disease.
What should you tell us before a flexible sigmoidoscopy?
Tell your consultant all the medications you take, particularly any blood thinners such as clopidogrel, warfarin, or heparin), or if you are on iron tablets. Our general advice to patients having a flexible sigmoidoscopy is to:
- Stop taking clopidogrel 7 days before your procedure.*
- Stop taking iron tablets 7 days before your procedure.
- Stop taking warfarin 5 days before your colonoscopy.*
*Please check with your GP, cardiologist or anti-coagulant clinic to see if you need replacement medication.
Tell us if you have diabetes, as your medication may need to be adjusted on the day of your colonoscopy.
How do you prepare for a flexible sigmoidoscopy?
Decide whether or not you will have sedation. Not all patients need sedation as the procedure is only mildly uncomfortable.
To allow a clear view of the lower colon you are usually given an enema (a liquid is inserted into your rectum) when you arrive at the endoscopy unit. This encourages a bowel movement so that the lower colon is empty to improve the views of the sigmoidoscope.
What happens on the day?
Come to the endoscopy unit 30 minutes before your sigmoidoscopy. Although we always try to perform your sigmoidoscopy at the agreed time, sometimes there are delays so your time slot cannot be guaranteed. If there is a delay, you will be kept updated.
- When you arrive, you will be seen by one of our nursing team, who will ask you questions about your medical history, medications and allergies. If you have decided to have your sigmoidoscopy with sedation, a small plastic cannula will be inserted into a vein in your arm or hand.
- You will be asked if you understand and accept what is planned and we will then need your written consent to go ahead.
- A flexible sigmoidoscopy does not normally require sedation, but if you have chose this option, the sedative is given via the cannula just before the procedure starts. If you are given sedation, a small clip will be placed on your finger to monitor your pulse rate and oxygen levels. We will also give some extra oxygen via a small tube placed into your nose.
- Gas is gently infused into the colon to expand the bowel for the doctor to have good views. You may experience some discomfort from time to time but we aim to keep this to a minimum.
- Any abnormal areas are photographed and we may take a small sample of tissue, a biopsy, for further analysis.
- Many people over 50 have bowel polyps. These growths are not cancerous, but if they are left alone they can sometimes become cancers. If a polyp is seen in the lower colon there may also be other polyps further up. In this situation your consultant may advise a full colonoscopy to inspect the entire colon. This would allow all polyps to be removed. A colonoscopy requires strong oral laxatives to clear the bowel more thoroughly and needs to be performed on another day, and patients often choose to have sedation.
What are the risks of flexible sigmoidoscopy?
Serious complications are extremely rare during routine colonoscopy but these problems may happen:
- A perforation in the wall of the bowel, for example, happens less than once in every 10,000 procedures. You are at greater risk if you have a polyp that will need removing or if you have a tight narrowing (a stricture) in part of your bowel. In these more complex cases, the rate of perforation rises to about 1%. If a perforation does occur, you will need to stay in hospital for observation. Only some perforations need to be repaired surgically.
- Significant bleeding following sigmoidoscopy, even with polyp removal, is very rare but slight bleeding often occurs at the site of a biopsy. Serious bleeding needs immediate treatment and observation in hospital. Very few patients with bleeding need surgery.
What happens after a flexible sigmoidoscopy?
Your abdomen may feel sore or bloated for a while. If you have not had sedation you may go home as soon after the sigmoidoscopy as you wish.
If you have received sedation you should be able to leave when fully awake (usually about an hour), but you must be accompanied by a responsible adult. Sedation makes you sleepy but it also affects your judgement and the way you make decisions. If you have been sedated:
- Do not drive home or drive for 24 hours.
- Do no not operate machinery.
- Do not make any important decisions.
- Do not drink alcohol.
You will be reviewed before going home, to check all is well. Sometimes your consultant can discuss the visual results at the time, but biopsy results may take up to four working days to come back. It is best to make another outpatient appointment with your consultant to discuss all the findings.
Unwell after your flexible sigmoidoscopy?
Complications are rare but if you experience any of these problems, please seek medical advice and contact us urgently:
- Severe persistent pain.
- Light-headedness or fainting.
- Passing of blood when you go to the toilet.
Getting more information
If you have any questions concerning your procedure, please contact the gastroenterology/hepatology team at The Physicians' Clinic
The team is available Mon – Fri 0900-1700
Tel: 020 7034 8164
Fax: 020 7034 8140
￼￼￼￼If you experience problems:
- Contact your consultant directly by telephoning The Physicians' Clinic during office hours as above.
- Out of hours, please contact your gastroenterologist directly using the information supplied after your appointment.