The aim of the examination is to find out what is happening in the large bowel to cause the symptoms you have. This means that the correct treatment can be given for your condition.
The colonoscopy gives a direct view of the lining of the large bowel, compared with just shadows seen on a barium enema x-ray.
If we suspect irritable bowel syndrome is the cause of your symptoms we do not expect to see anything abnormal, because the cramped muscle does not show up during this examination. The examination can be used to check there is nothing else apart from the irritable bowel.
During the colonoscopy we can take small samples of the bowel lining, called biopsies, for examination under the microscope. We can also remove polyps, if any are found.
The large bowel may be seen to be normal, but there is a small chance of missing a condition, as the colonoscopy is not fail proof.
Are there any alternatives?
You will probably have a series of tests to find out what is causing your symptoms. For example, you may have a barium enema. A liquid that shows up on x-rays, called barium sulphate, is passed into the bowel through the anus. A series of x-rays are taken from different angles to show up as much of the bowel as possible. If the barium enema showed you had a polyp, you may then have a colonoscopy to have it removed.
There is another examination, similar to a colonoscopy, called a sigmoidoscopy. The endoscope used here is shorter and your doctor may recommend this test if he thinks, for instance, that any bleeding is coming from a haemorrhoid or a polyp a short way up your bowel.
There are tests of your stools that can be done to check for bleeding, such as the faecal occult blood test.
What if you do nothing?
If you have symptoms, such as blood in your stools, they should be investigated, as leaving things as they are can be very risky. You may be missing out on important treatment.
Author: Mr Michael Edwards FRCSEng FRCSEd. Consultant general surgeon.
© Dumas Ltd 2006