Colonoscopy refers to the passage of a fibreoptic telescope through the entire colon under sedation. Colonoscopy allows the doctor to inspect the lining of the colon and to make optical diagnoses of bowel disease. It also allows biopsies to be performed and any polyps, mucosal elevations composed of abnormal cells, can be excised.
Colonoscopy requires sedation by an anaesthetist for about 30 minutes so that the colonoscope can be passed without pain or distress to the patient. Two days before colonoscopy, bowel preparation commences with a fluid only diet. One day before colonoscopy, bowel preparation is taken. This is a laxative solution which flushes the faecal material from the bowel and ensures that the colon is clean for the procedure. On the day of colonoscopy, sedation is administered therefore, patients cannot drive themselves home.
Colonoscopies are required after faecal occult blood tests are reported as positive. These tests, which are distributed by the government when patients reach 50 years of age, detect microscopic traces of blood in the stools. They are quite sensitive and can alert the patient and doctor to the presence of colonic polyps and colonic cancer.
For the population, colonoscopy and the removal of pre-cancerous polyps can be effective at preventing colon cancer. Colonoscopies do have risks and the most important risks include: missed pathology or failure to detect disease which is actually present, colonoscopic perforation of the bowel, post polypectomy bleeding and post procedure irritable bowel syndrome. The chances of complication are low and the main benefit is significant given that approximately 40% of colonoscopies allow for the removal of pre-malignant polyps.
Prior to a colonoscopy, some medications have to be ceased or managed differently. Anticoagulants taken for clots or irregular heart beats must be stopped 2-5 days before the procedure. Antiplatelet agents like Clopidogrel and Aspirin are usually at least one week before the scope. Similarly, diabetic medications may need to be ceased or altered when fasting for procedures.