A colonoscopy is a frequently performed test to investigate the lower part of the bowel. This is an endoscopic test that allows the consultant to look directly at the lining of the bowel. Colonoscopy can detect inflammatory bowel disease, polyps and cancers.
The procedure is used to help doctors diagnose unexplained changes in bowel habits (for example constipation or diarrhoea), abdominal pain, bleeding and weight loss. Biopsies can also be taken during the procedure and polyps can be removed.
Do I need any preparation before-hand?
You will receive written instructions about the test beforehand. You will be given some strong laxatives to clear out the bowel (Picolax). It is important that you follow the instructions carefully and you should drink as much clear fluid as possible. Having a clean bowel will allow the doctor to be able to see the lining more accurately.
You will be having sedation or an anaesthetic for the procedure and you will instructed when to stop drinking beforehand, again it is important that you adhere strictly to these instructions.
You should inform your doctor if you are diabetic or taking any medication that might thin the blood such as Aspirin, Clopidogrel or Warfarin.
What does the test involve?
The instrument used during this investigation is called a colonoscope. This is a long flexible tube with a light at the end. It is passed through the anus. This allows the doctor to see images of the inside of your bowel on a screen. In most cases the doctor can see the whole of the colon and sometimes the last part of the small intestine (terminal ileum) as well.
The doctor can remove growths, called polyps, during colonoscopy using special tools passed through the scope. During a colonoscopy, the doctor can also take samples of tissue called biopsies from normal and abnormal-looking tissues.
What are the possible risks?
Colonoscopy is commonly performed and generally safe, complications are rare. Colonoscopy carries a very small risk of perforation (tear) of the bowel. If polyps are removed or biopsies taken bleeding may occur from the site. This is usually minor and may stop on its own or require treatment using a heat probe or injection through the colonoscope.
Side effects from sedatives (if given) are rare. These can include problems with your breathing, blood pressure and heart rate. These are usually short lived and quickly treated. Sometimes it may not be possible to complete your procedure successfully and it may need to be done again. If you develop severe pain or persistent bleeding after you have gone home you should contact the hospital, your own GP or your local A&E department immediately, for further advice.
What happens afterwards?
A colonoscopy takes about 30 minutes to complete. You may feel bloated and have some wind-like pains afterwards. These usually settle very quickly. As you have had sedation or an anaesthetic for the procedure you will need to recover fully before going home (please see advice sheet for more information).
The consultant will be able to tell you the result straight after the procedure. The pathologist will process any tissue samples taken and the results will be available within a few days.