What is a Colonoscopy?

A colonoscopy is a procedure performed under light sedation in hospital to investigate and diagnose several problems involving the colon (large bowel). It is performed using an instrument called a colonoscope which is a flexible tube camera that is about the thickness of a finger. It is inserted via the rectum into the colon and allows the surgeon to carefully examine the lining of the bowel. Any abnormalities may be sampled (biopsied) and examined in the laboratory to assist with diagnosis.  

What are the indications for a colonoscopy?

Indications for a colonoscopy may include but are not limited to any of the following:

  • Family or personal history of colonic polyps or bowel cancer

  • Known medical condition that increases risk of bowel cancer

  • Symptoms of bowel cancer

    • Bleeding from the bowel

    • Positive screening faecal occult blood test

    • Anaemia (low blood count)

    • Iron deficiency

    • Change in bowel habits

    • Unexplained weight loss

    • Abdominal/rectal mass

  • Suspicious findings on investigations

What Is a Polypectomy?
Polyps are an excessive growth of tissue within the lining of the large bowel wall. They vary in size, location and numbers and can occur anywhere throughout the large bowel.  Some polyps can develop cancer. Removal of polyps prior to cancerous changes can prevent bowel cancer. During a colonoscopy the polyps seen will be removed if possible or biopsied if too large to removed during colonoscopy. This is achieved by passing a wire loop through the colonoscope and snaring the base of the polyp, which is then severed from its attachment to the bowel wall by means of an electric current. This current cannot be felt and causes no pain. After colonoscopy polypectomy the patient is allowed to resume usual activities.  If the polyp was too large to be removed the surgeon will discuss further treatment.


 Is Any Special Preparation Necessary?
Yes. For a successful colonoscopy, it is essential that the bowel is thoroughly emptied. This will usually mean taking clear liquids as well as a special laxative at home before the colonoscopy. More specific preparation instructions will be given to you. 

What Happens After Colonoscopy?
Following the colonoscopy, once you are fully awake you will usually be able to resume a normal diet and go home the same day.  You will need to have a responsible adult with you for the first 24 hours and cannot drive during this period due to the effects of the anaesthetic.  You will be followed up by the surgeon in the following week with the results of the procedure and any biopsies/polypectomy explained.  Any further procedures or management will be based on the findings.

Are There Any Complications From Colonoscopy Or Polypectomy?
Colonoscopy and polypectomy are very safe procedures with a very low risk of complications. Possible complications include:

  • 1 in 1000 risk of bowel perforation

  • Missed lesion

  • Bleeding

  • Infection

  • Pain

  • Further procedures

  • Anaesthetics