Also called a lower endoscopy, a colonoscopy is a visual examination of the colon or large intestine using a flexible scope called a colonoscope. The scope features a lighted camera designed to take real-time images or video of the interior of the colon, sending those images to a video monitor where they can be viewed by the doctor performing the procedure.
Colonoscopies are performed to diagnose symptoms like chronic pain and bloating, chronic diarrhea or constipation, or other symptoms affecting the lower bowel. The procedure is also used routinely to screen for colorectal cancer. In addition to screening for colon cancer, colonoscopies are used to diagnose or treat:
Prior to having a colonoscopy, the bowel must be completely emptied and clean. The day before the procedure, patients will need to drink a special solution designed to flush out the colon. During this time, the patient will need to be near a toilet to empty the bowels as the solution takes effect. Patients will also need to drink only clear fluids and avoid food for at least part of the day prior to the exam, and patients who take medications may need to alter their dosing schedules based on the doctor’s recommendations. The procedure itself is performed while the patient is sedated (in a deep sleep), with medication delivered through an intravenous catheter. Once sedation is administered, the camera is inserted into the anus and slowly advanced through the colon. An inert gas is usually used to gently expand the colon to make it easier to view. If polyps or areas of abnormal tissue are seen, special instruments will be used to remove or sample them. Procedures take about 20 to 30 minutes and patients can return home the same day.