A colonoscopy is a specialised 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 the areas to be examined.
Why do I need this procedure?
This test has been recommended to you to help your doctor evaluate symptoms of the lower digestive tract, to find out if your large intestine is healthy or diseased. The large intestine is the site of numerous disorders ranging from haemorrhoids (piles) to polyps to cancer. If needed, and where technically possible, treatment can also be performed through the colonoscope, at the same examination. For example, a polyp can be painlessly removed through the colonoscope using electrocautery (electrical heat).
What does it involve?
You will receive instructions in advance to help you prepare for this test. You will need to take medication to clean out your large intestine one day before the test, so that clear views can be obtained. During the procedure, everything will be done to make you as comfortable as possible. 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.
Lubricant will be applied into your anus. A fingertip examination of the anal canal is first carried out. 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 excluding preparation time. In some cases, it may be necessary to take a sample of tissue (biopsy) for examination.
What are the possible complications from a colonoscopy?
Although colonoscopy is a safe procedure, complications can sometimes occur. Care will be taken to minimise discomfort and complications as far as possible. Mild problems such as bloating, gas or mild cramping may occur and can last up to 24 hours. Heavy bleeding may occur after removal of a polyp and sometimes 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 the polyps. This will require hospitalisation and even surgery. Bleeding and perforation occur in less than 1 in 1000 cases. The risk is increased with procedures such as polyp removal. The risks of sedation include lowering blood pressure, lowering oxygen level and slowing down breathing. This is minimised by using the appropriate dose of sedative and monitoring of pulse and oxygen levels. Rarely, these complications can be fatal.
What can I expect after a colonoscopy?
After the procedure, you will be brought 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. Your doctor will make an appointment for you to let you know the findings of the colonoscopy, answer any questions you may have and, if needed, discuss treatment.
Is there an alternative test?
The alternative to colonoscopy is a barium enema examination. This is an x-ray investigation involving the administration of a white liquid (barium) and air through the anal canal to outline the large intestine. A biopsy and treatment (e.g. removal of polyps) will not be possible with this test.