What is a colonoscopy?
A colonoscopy is an examination of the large bowel (colon) using a colonoscope - a narrow flexible fibre-optic tube equipped with a camera and a strong light and display the images on a monitor. The colonoscope has two channels one for blowing air and sucking fluid and the other for passage of fine instruments for taking samples (biopsies), removing polyps or injections.
Why is this test done?
Colonoscopy is performed to examine the large intestine to investigate problems suchs as:
- bleeding from the back passage
- change in bowel habits
- abdominal pain
- prolonged diarrhoea
- a positive fecal occult blood test (a test for the presence of blood in the stool)
- screening or follow-up (surveillance) of colonic polyps or cancer
Do I have to prepare for the procedure?
In order to be able to examine the bowel fully and to make the colonoscopy easier and safer, it is vital that your large bowel is cleaned out of all waste material. To achieve this you will be given a preparation kit with full instructions. This usually means having a special diet for two days and nothing but clear fluids for 24 hours before the test. One that day before the procedure you take the special laxative and this is usually enough to clear the bowel. Patients who suffer from long standing constipation may need an enema on the morning of the test if the preparation was inadequate.
Do I continue to take my normal medications as usual?
Most medications should be continued as usual, others need to be stopped to changed to safe alternative few days before the procedure. It is important to discuss with me or your GP your current medications. In particular, if you have diabetes, heart disease, or take drugs that thin the blood me know in order to make the necessary adjustments.
What happens during the colonoscopy?
After arriving to the hospital the nurse will check you in and you will change into a hospital gown. The anaesthetist will see you and put a needle in the back of your hand. I will see you again before the procedure and answer any last minute questions. Inside the endoscopy suite you will lie on your left side, Oxygen and monitors are attached and the anaesthetist will give you sedation. When you are fully sedated, the examination is commenced.
During the examination I will pump air inside the colon to open up the bowel to have good views as I examine the bowel fully to where the small bowel joins the large bowel. After that I withdraw the scope slowly to have a second view on the way back.
If there are any abnormalities such polyps or tumour I will take biopsies (samples) or remove them with a snare. Both these procedures are painless.
What happens after the colonoscopy?
When the procedure is over you will be taken to the recovery room while the sedation wears off. Though I try and suck most of the air I pumped at the end of the procedure you may experience some wind pain. This will settle after you pass wind.
When you are fully awake you will be taken to discharge area and will be given a well deserved hot drink and a sandwich. I will discuss with you the findings and the plan before you go home but it is not uncommon that you will not remember much of this due to the effect of sedation. You will be given a copy of the report with you and I will send a copy to your GP as well.
You should have a friend or a relative take you home and stay will you for 24 hours. You should not drive a car, travel on public transport alone or operate heavy machinery for 12 hours after the test.
What are the risks of colonoscopy?
Although serious complications are rare, problems can occur:
- Missing an abnormality. Colonoscopy provides the most accurate assessment of the colon, however, no test is perfect and there is a risk that an abnormality may not be detected.
- Intolerance to the bowel preparation. Some patients develop dizziness, headache or vomiting.
- Reaction to the sedatives or anaesthetics. This is rare but is of concern in patients with severe heart or lung disease.
- Perforation (making a hole in the bowel). This is very rare occurring 1 in 1000 cases. Surgery is usually required for repair.
- Significant bleeding from the bowel. This usually happens after removal of a polyp and is more likely to occur in patients taking drugs that thin the blood. Blood transfusion or repeat colonoscopy may be required and very rarely surgery is needed.
- Other rare complications
Sterilization of the colonoscope and all Instruments.
The colonoscope and all other instruments are completely cleaned and disinfected between each patient to avoid the risk of transmission of serious diseases such as HIV, Hepatitis B or C.
What are the Red Flags after colonoscopy?
If you develop any of the following symptoms in the hours or days after your colonoscopy you should contact me and your GP and present to the emergency department:
- severe abdominal pain
- persistent bleeding
- black tarry bowel movements
- fever or shivering
- any other symptoms that cause you concern.