What is a colonoscopy?

What is a colonoscopy?

A colonoscopy is a procedure done to examine your large bowel (colon) by passing a thin long, flexible tube with a small video on the tip through the bottom. This is done under deep sedation (you are not awake for the procedure). An anaesthetic specialist is present at the colonoscopy to manage the sedation. The test usually takes 20-30 minutes but may be longer for some patients.

The images from the thin tube are displayed onto a video monitor at the bedside. Your doctor takes time and care to explore the large bowel carefully, looking for any abnormality that may explain your symptoms. Colonoscopy can also be used to find bowel cancer, remove polyps, stop internal bleeding and treat piles.

Small samples (biopsies) may be taken by passing small forceps in through the scope. Biopsies are very small and do not cause you any discomfort. The samples and any polyps removed are sent to the lab for further testing by a specialist pathologist, and results are available within 3-5 days. Removal of larger polyps may require electricity current (diathermy). It is important therefore to inform your doctor and the hospital of any pacemaker, metal implants and metal piercings as they may conduct heat

Are there any risks with the procedure?

A colonoscopy is considered a safe test. A minority of patients wakes up with mild short term bloating. Risks are uncommon and great care is taken to avoid these. These can include:

  1. Aspiration- stomach contents entering the lungs- 1 in 2000

  2. Bleeding- 1 in 2000

  3. Perforation/tear in the lining- rare

  4. Missed colonic lesion - uncommon

  5. Complications from the anaesthetic- rare

How do you prepare for a colonoscopy?

In order to visualise your colon completely, your colon must be completely emptied of waste by drinking laxatives and following a special diet. Refer to the bowel preparation instructions for more details on the instructions and fasting time.

You can drink CLEAR FLUIDS only until 2 hours before your admission time. CLEAR FLUIDS are: water, soda water, mineral water, cordial, sports drinks, lemonade, apple juice (no pulp), black coffee/tea.

Take your usual medication on the morning of the test with water (more than 2 hours before the test). If you are on insulin, diabetic medication or blood thinners, please seek advice from the Gastroenterologist about these medications before the test.