What is involved in a colonoscopy / polypectomy?
A colonoscope comprises a long thin tube equipped with a camera and light on the tip, as well as some miniaturised surgical instruments. It is introduced via the anus and is then navigated through the bowel, allowing the operator to view the bowel wall and detect any abnormalities, such as polyps, and take tissue samples (biopsies).
Polyps are small raised sections in the bowel lining (they can be anything from a few millimetres to six centimetres in diameter), and most types of polyps can be removed during a colonoscopy in a process referred to as 'polypectomy'. Of the many different types of polyps, most are not cancerous.
Two common types are known as 'adenomatous' and 'hyperplastic' polyps, although they appear very similar and can only be differentiated from each other during pathology testing. Cancer - if present - is more likely to occur in adenomatous polyps. Most polyps cause no symptoms, although larger ones can cause bleeding and are more likely to contain cancer cells.
The removal of polyps during the colonoscopy involves a wire loop being passed around the polyp/s and then tightened, simultaneously applying an electric current to the wire.
When is a colonoscopy / polypectomy recommended?
If the patient has either a history of bowel cancer in the family, or personally has had inflammatory bowel disease, or has had polyps removed in the past, they may be recommended to have regular colonoscopy screening. In other cases, for example where there has been a persistent change in bowel habit or if there has been any bleeding from the anus (whether visible or detected in a Faecal Occult Blood Test - FOBT), a doctor may recommend a colonoscopy.
Are there alternatives to colonoscopy / polypectomy?
A so-called 'virtual colonoscopy' may be an option. This is a CT scan carried out after the bowel has been cleansed and a small amount of air is blown into the colon via the anus. However, if there are any abnormal results, a conventional colonoscopy will be required.
The colon must be completely cleansed, that is completely empty, when the colonoscopy is conducted. You will need to have a three-sachet pack of a special preparation called Picoprep which will help cleanse the bowel. This can be bought at our office or at any pharmacy.
To prepare the bowel for the procedure, the following process must be followed:
One week before
Any iron tablets being taken must be stopped. Other medications, such as anticoagulant medications can be taken as usual unless advised otherwise by the specialist.
The day before
Breakfast can be eaten as normal in the morning, but after breakfast no solid food should be eaten. Clear liquids (a liquid is clear if you can see clearly through the glass) can be taken.
You should drink plenty of water, and in addition, the following types of liquids can also be drunk:
- Clear soups, consommes, stock, broths etc.
- Black coffee (no milk).
- Black tea (no milk).
- Cordials / fruit juices (but no juices with solid matter or pulp in them).
Avoid any drinks that are red or purple in colour.
The Picoprep solution, which you make up by completely dissolving one sachet into 250ml of warm water (roughly a glass), should be taken on the day before the procedure at the following times:
- Sachet 1 - 12pm midday.
- Sachet 2 - 3pm.
- Sachet 3 - 6pm.
At each time slowly drink the solution over 5-10 minutes and then drink 3-4 glasses of water or one of the drinks listed above over the next 30-40 minutes. You can cool the solution before you drink it if you prefer. Picoprep creates a very watery motion which allows the bowel to cleanse and empty. You may want to apply lanolin or a similar cream to the area around the anus to prevent any soreness.
The day of the procedure
Do not eat or drink anything at all ('nil by mouth') after midnight on the day before the procedure.