What is a Colonoscopy?
A colonoscopy is a specialized examination that allows your doctor to look inside your large intestine. A colonoscope is a long, thin and flexible tube. It has a video camera attached to one end and controls at the other end. Your doctor can guide the colonoscope safely to examine your large intestine / colon.
Why do I need this procedure?
This test will help your doctor evaluate symptoms of the lower digestive tract. Colonoscopy is also the recommended test for screening of colon cancer. The large intestine is the site of numerous disorders such as haemorrhoids (piles), colitis, polyps and colon cancer. If needed, and where technically possible, treatment can also be performed through the colonoscope during the examination. For example, a polyp can be painlessly removed through the colonoscope using electrocautery (electrical heat).
What does it involve?
You will need to take medication to clean out your large intestine one day before the test, so that clear views can be obtained. Colonoscopy is done with you lying on your left side. An injection of a sedative and painkiller is usually given to make you relaxed and go into a light sleep. Your pulse and oxygen level will be monitored with a finger-probe throughout the procedure.
The colonoscope is then gently introduced into the anus and steered through the entire large intestine. Occasionally you may feel some discomfort during the procedure when the colonoscope is going round a sharp bend of the intestine. The entire procedure takes between 15 and 30 minutes. In some cases, it may be necessary to take a sample of tissues (biopsy) for examination.
What are the possible complications from a colonoscopy?
Although colonoscopy is a safe procedure, complications can sometimes occur. Mild discomfort such as bloating may occur and can last up to 24 hours. Heavy bleeding may occur after removal of a polyp and sometimes may require transfusion or reinsertion of the colonoscope to control the bleeding. Perforation (tear of the intestine wall) may occur from the manipulation of the scope or removal of polyp. Bleeding and perforation occur in less than 1 in 1000 cases. The risk is increased if large polyps are removed. These two complications can be controlled by repeating the colonoscopy with application of clip(s). Sometimes, surgery may be required to control bleeding or close the perforation. The risks of sedation include lowering of blood pressure, lowering of oxygen level and slowing down of breathing. This is minimized by using the appropriate dose of sedative and monitoring pulse and oxygen level. Rarely, these complications can be fatal. Small polyps can be missed during colonoscopy especially if you still have large amount of faeces in your colon. Your doctor will minimize this risk by careful inspection but it is essential that you complete the medications given to you to clear your bowel. If ligation (banding) of haemorrhoids is performed, there could be possible complications of post ligation bleeding, pain and infection.
What can I expect after a colonoscopy?
After the procedure, you will be brought back to the recovery area for monitoring and observation. You should not drive or operate machinery on the same day. For this reason, someone else must be available to accompany you home.
Is there an alternative test?
The alternatives to colonoscopy are barium enema examination and CT colonography. Barium enema is an x-ray investigation involving the administration of a white liquid (barium) and air through the anal canal to outline the large intestine. This test is seldom performed due to lack of accuracy. CT colonography is also an x-ray examination involving radiation and administration of air through the anal canal. With the help of computer software, your doctor will be able to perform a “virtual colonoscopy”. Both Barium enema and CT colonography involve you taking laxatives prior to the procedure. CT colonography is much more accurate than Barium enema. Taking biopsy and removal of polyps will not be possible with Barium enema and CT colonography. Therefore, if there is any abnormality detected, you will have to undergo colonoscopy.
What should I do with my current medication before the procedure?
You need to inform your list of medication (including traditional medicine) to your doctor. In general, you need to stop blood thinning medicines (such as clopidrogel, warfarin, Xarelto, Pradaxa) before the procedure. Your doctor will advise you the number of days you need to stop the medication. You also need to inform your prescriber whether it is safe to stop these medication temporarily. Another group of medication which you need to stop before the procedure are diabetic medicines.