What is a colonoscopy?
A colonoscopy is a procedure in which your doctor is able to visualise the inside of the large bowel in order to check for abnormalities and confirm a diagnosis. The procedure is carried out by a doctor trained in endoscopy and provides a very accurate means of looking at the lining of the large intestine to establish whether disease is present.
A fibreoptic tube with high definition imaging is used to perform the procedure. The instrument comprises a scope, which directs light onto the lining of the bowel, as well as a camera that sends high definition images /pictures to a screen where they can be carefully examined by the endoscopist.
A colonoscopy also allows biopsies (small pieces of tissue) to be taken for examination by a pathologist to confirm the presence of disease.
The procedure is relatively painless for a number of reasons: the experience and skills of your gastroenterologist; the type of sedation that is used; and the type of gas that is used to insufflate the colon. The more experienced your endoscopist, the more skilled he or she will be at completing the colonoscopy without patient discomfort.
A colon inflated with air can cause significant discomfort after the procedure, whereas a colon inflated with carbon dioxide makes the procedure much better tolerated.
The type of sedation used is called deep conscious sedation, which is not a general anaesthetic as the patient is able to breathe by themselves. However, we use a special gadget to monitor the depth of sedation and this ensures that the patient is fully sedated during the colonoscopy and will not wake up with pain.
When is a colonoscopy performed?
A colonoscopy may be recommended in the following cases:
- Change in bowel habits
- Bleeding per rectum
- Lower abdominal pain
- Chronic recurrent diarrhoea
- Unexplained weight loss
- Iron deficiency
- Age over 45— to pre-emptively detect polyps or cancer
- Family history of early colorectal cancer
- Suspected inflammatory bowel disease
- Suspected colon cancer
- To remove detected polyps carefully to prevent the progression of cancer
What does the procedure involve?
Before the procedure begins, your doctor will provide you with instructions on how to prepare. You will need to follow a clear liquid diet for 24 hours before your colonoscopy. You will need to take a colon lavage/prep fluid. This is absolutely crucial as a poorly prepped colon potentially prevents detection of pathology that can have significant consequences. The prep is taken the day before the procedure and on the day of the procedure. By splitting the colon prep, studies have shown that better results are obtained.
First, you will be asked to change into a special gown. You will then be asked to lie on your side, and you will be given a sedative before the procedure begins. During the procedure, your doctor, assisted by a specially trained endoscopy nurse, will insert the scope into your anus and guide it carefully under direct vision, through the rectum and into the colon. Your colon will be inflated with gas, which allows your doctor to view the inside of your large bowel in detail.