COLONOSCOPY

The colon or large bowel (large intestine) is approximately 1.8 metres long & opens into the rectum (about 10 cm) which is continued as the anal canal (2.5 - 3.5 cm), Click on Diagram of the Gastro-intestinal (Digestive) Tract to see picture. Its direct examination with a flexible (bendy) telescope inserted through the anus is called colonoscopy. It is an excellent way of examining the colon because if an abnormality is detected it can be biopsied (small piece removed for examination under the microscope) or small polyps can be "burnt off".

What it involves for the patient:

You will need to undergo "bowel preparation", i.e. take laxatives & a low-residue diet for 2 days to clear all the faeces from the colon - otherwise a complete examination is not possible - see separate section for Bowel Preparation.

During the bowel preparation expect a lot of diarrhoea - which means you should have easy access to a toilet.

For the examination itself you will need to come into a hospital, usually the Endoscopy Unit, about an hour before the expected time of the procedure. A nurse will ask some questions about your health, take your blood pressure and ask you to change in to a gown. In the endoscopy room you will lie on a trolley on your left side. The nurse will place 2 small tubes close to your nostrils to deliver oxygen. A small soft sensor clip will be attached to one of your fingers to monitor your pulse and oxygen levels. These are routine procedures & should not alarm you. During the procedure, and sometimes before, a soft sticky pad may be placed on your thigh - this is necessary in case anything in your colon needs to be diathermied (brunt off). Two nurses will be present throughout the procedure. A small needle is placed into a vein in your hand or forearm & sedatives are injected to make you sleepy & relaxed. This is not a general anaesthetic & is referred to as "sedation".

While you are lying on your left side, The colonoscope which has been lubricated with a clear jelly is gently inserted into your anus (back passage) & advance slowly. During the examination you may feel a little bloated & may experience some cramp-like wind pains, which is due to air passing into your colon from the colonoscope. There is often no real discomfort. You may get the sensation of wanting to go to the toilet to pass motions but this is just a sensation because the bowel is empty and there is no danger of this happening. You may pass a lot of wind during the procedure, but please don't be embarrassed, as this is the air that has been placed into your colon, and its escape is inevitable. During the procedure it is important for you to relax as much as possible & take your mind off the procedure by thinking about more pleasant things. Best of all try and drift into sleep.

After the colonoscopy is complete, you rest or, more usually sleep, for a couple of hours. You may feel bloated, and pass wind. After you have recovered (usually 2 hours) you can go home but you cannot drive, operate machinery or drink alcohol that day and it would be best if someone can accompany you home. You can carry on normally the following day. If biopsies have been taken the results will not available for 1 - 2 days. The full result can be communicated to you by telephone as soon as they are available, if this is before your follow up appointment.