The colon, or large bowel, is the last portion of your digestive tract, or gastrointestinal tract. The colon is a hollow tube that starts at the end of the small intestine and ends at the rectum and anus. The colon is about 5 feet long, and its main function is to store unabsorbed food waste and absorb water and other body fluids before the waste is eliminated as stool.
You will be given instructions in advance that will explain what you need to do to prepare for your colonoscopy. Your colon must be completely empty for the colonoscopy to be thorough and safe; therefore, thorough cleansing of the bowel the night before your procedure is necessary before a colonoscopy.
Be sure to inform your doctor of any medical conditions you have or medications you take on a regular basis such as:
The medical staff will also want to know if you have heart disease, lung disease or any medical condition that may need special attention. You must also arrange for someone to take you home afterward, because you will not be allowed to drive after being sedated.
For the colonoscopy, you will lie on your left side on the examining table. You will be given intravenous sedation (IV) to keep you comfortable and help you relax during the exam. The doctor and a nurse will monitor your vital signs, look for any signs of discomfort, and make adjustments as needed.
The doctor will then insert a long, flexible, lighted tube into your rectum and slowly guide it into your colon. The tube is called a colonoscope (koh-LON-oh-skope). The scope transmits an image of the inside of the colon onto a video screen so the doctor can carefully examine the lining of the colon. The scope bends so the doctor can move it around the curves of your colon.
Air is introduced into the colon which will inflate the colon aiding your doctor in complete visualization. Most patients do not remember the procedure afterwards.
At the time of the procedure your doctor can remove most abnormal growths in your colon, like a polyp, which is a growth in the lining of the bowel. Polyps are removed using tiny tools passed through the scope. Most polyps are not cancerous, but they could turn into cancer. Just looking at a polyp is not enough to tell if it is cancerous. The polyps are sent to a lab for testing. By identifying and removing polyps, a colonoscopy likely prevents most cancers from forming.
The doctor can also remove tissue samples to test in the lab for diseases of the colon (biopsy). In addition, if any bleeding occurs in the colon during the procedure, the doctor can pass a laser, heater probe, electrical probe, or special medicines through the scope to stop the bleeding. The tissue removal and treatments to stop bleeding usually do not cause pain. In many cases, a colonoscopy allows for accurate diagnosis and treatment of colon abnormalities without the need for a major operation.
When the doctor has finished, the colonoscope is slowly withdrawn while the lining of your bowel is carefully examined.
Bleeding and puncture of the colon requiring surgical repair are possible but uncommon complications of a colonoscopy.
A colonoscopy usually takes 30 to 60 minutes. The sedation should keep you from feeling much discomfort during the exam. You may feel some cramping or the sensation of having gas after the procedure is completed, but it usually stops within an hour. You will need to remain at the colonoscopy facility for a period of recovery time.
Rarely, some people experience severe abdominal pain, fever, bloody bowel movements, dizziness, or weakness afterward. If you have any of these side effects, contact your physician immediately. Read your discharge instructions carefully. Full recovery by the next day is normal and expected and you may return to your regular activities.