What is a colonoscopy?
The doctor looks at the lining of your large bowel to see if there are any growths or disease.
This is done by putting a bendable tube (colonoscope) with a camera attached, into your back passage. The tube is then slowly passed into the rectum and large bowel (colon). Pictures of the inside of your bowel are then seen on a video screen.
You will lie on your side or back while your doctor slowly passes a colonoscope along your large intestine to look at the lining. Your doctor will examine the lining again as the colonoscope is taken out.
You might feel some pressure, bloating or cramping during the procedure. You should plan on two to three hours for waiting, preparation and recovery. The procedure itself usually takes anywhere from 15 to 60 minutes.
What are risks of a colonoscopy?
There are some risks and complications, which can happen. These include:
(a) The bowel may be punctured. This can cause leakage of bowel contents into the abdomen. The risk is higher when polyps are removed, depending how large the polyp is. This is treated by keeping the bowel empty using suction and a tube into the stomach or bowel via the nose. Fluids and antibiotics are given via a drip, and further surgery may be needed. This may require a longer stay in hospital.
(b) Bleeding from the bowel following biopsy and/or removal of a polyp/polyps. This may be oozing from where the polyps were removed or damage of large blood vessels.
The risk may be greater the larger the polyp. Sometimes bleeding can happen up to 12 days afterwards. This usually settles without further treatment. Another colonoscopy may be done to stop the bleeding. Rarely, a blood transfusion and further surgery may be needed if there is a lot of bleeding.
(c) The procedure may not be able to be completed due to bowel disease or other problems. Polyps or cancer can be missed. The risks are higher if your bowel is not cleaned properly. It is important that you follow the instructions to clear your bowel before the procedure.
(d) Mild pain and discomfort in the abdomen for one or two days after the procedure. This is treated with pain relief. It usually settles without further treatment.
(e) Very rarely, heart and lung problems such as:
- low oxygen levels
- lowered blood pressure
- higher pulse rate
- pneumonia (caused by vomit going down the lungs)
People with ill health are more at risk. Healthy people may feel very drowsy for a few days afterwards. The procedure is immediately stopped if anything happens. Rarely, drugs may be given to take away the effects of the sedation and at worse life saving procedures may be needed.
(f) Death due to complications of colonoscopy is extremely rare.