The term "colonoscopy" means looking inside the colon. It is a procedure performed by a gastroenterologist, a well-trained subspecialist.
The colon, or large bowel, is the last portion of your digestive or GI tract. It starts at the cecum, which attaches to the end of the small intestine, and it ends at the rectum and anus. The colon is a hollow tube, about five feet long, and its main function is to store unabsorbed food products prior to their elimination.
The main instrument that is used to look inside the colon is the colonoscope, which is a long, thin, flexible tube with a tiny video camera and a light on the end. By adjusting the various controls on the colonoscope, the gastroenterologist can carefully guide the instrument in any direction to look at the inside of the colon. The high quality picture from the colonoscope is shown on a TV monitor, and gives a clear, detailed view.
Colonoscopy is more precise than an X-ray. This procedure also allows other instruments to be passed through the colonoscope. These may be used, for example, to painlessly remove a suspicious-looking growth or to take a biopsy, a small piece, for further analysis. In this way, colonoscopy may help to avoid surgery or to better define what type of surgery may need to be done.
Colonoscopy is a safe and effective way to evaluate problems such as blood loss, pain, and changes in bowel habits such as chronic diarrhea or abnormalities that may have first been detected by other tests. Colonoscopy can also identify and treat active bleeding from the bowel.
Colonoscopy is the most accurate test to screen for colorectal cancer, but there is approximately an 8% chance that colorectal cancer will be missed during a colonscopy.
Colonoscopy is also an important way to check for colon cancer and to treat colon polyps, abnormal growths on the inside lining of the intestine. Polyps vary in size and shape and, while most are not cancerous, some may turn into cancer. However, it is not possible to tell just by looking at a polyp if it is malignant or potentially malignant. This is why colonoscopy is often used to remove polyps, a technique called a polypectomy.
There are important steps that you must take to prepare for the procedure. First, be prepared to give a complete list of all the medicines you are taking, as well as any allergies you have to drugs or other substances. Your medical team will also want to know if you have any other medical conditions that may need special attention before, during, or after the colonoscopy.
You will be given instructions in advance that will outline what you should and should not do in preparation for colonoscopy. Be sure to read and follow these instructions. One very critical step is to thoroughly clean out the colon, which, for many patients, can be the most trying part of the entire exam. It is essential that you complete this step carefully, because how well the bowel is emptied determines the success of the procedure.
Various methods can be used to help cleanse the bowel. Often, a liquid preparation designed to stimulate bowel movements is given by mouth, which may cause bloating. Additional approaches include special diets or the use of enemas. Whatever method or combination of methods that is recommended for you, be sure to follow instructions as directed.
And remember, you should not consume anything within eight to ten hours before your colonoscopy.
Colonoscopy can be done in either a hospital or outpatient facility. You'll be asked to sign a form that gives your consent to the procedure and states that you understand what is involved. If there is anything you don't understand, ask for more information.
During the procedure, everything will be done to ensure your comfort. An intravenous, or IV, line will be inserted to give you medication to make you relaxed and drowsy. The drug may enable you to remain awake and cooperative, but it may prevent you from remembering much of the experience.
Once you are fully relaxed, your doctor will do a rectal exam with a gloved, lubricated finger; then the lubricated colonoscope will be gently inserted.
As the scope is slowly and carefully passed, you may feel as if you need to move your bowels, and because air is introduced to help advance the scope, you may feel some cramping or fullness. Generally, however, there is little or no discomfort.
The time needed for colonoscopy will vary, but on the average, the procedure takes about 30 minutes. Afterwards, you will be cared for in a recovery area until the effects of the medication have worn off. At this time, your doctor will inform you about the results of your colonoscopy and provide any additional information that you need to know. You'll also be given instructions about how soon you can eat and drink, plus other guidelines for resuming your normal routine.
Although colonoscopy is a safe procedure, complications can sometimes occur. These include perforation, a puncture of the colon walls, which could require surgical repair.
When polyp removal or biopsy is performed, hemorrhage (heavy bleeding) may result and sometimes require blood transfusion or reinsertion of the colonoscope to control the bleeding. Be sure to discuss any specific concerns you may have about the procedure with your doctor.
Occasionally, minor problems may persist, such as bloating, gas, or mild cramping. These symptoms should disappear in 24 hours or less. By the time you're ready to go home, you'll feel stronger and more alert. Nevertheless, rest for the remainder of the day. Have a family member or friend take you home.
A day or so after you're home, you might speak with a member of the colonoscopy team for follow up, or you may have questions you want to ask the doctor directly.