A colonoscopy is an exam of the lower part of the gastrointestinal tract, which is called the colon or large intestine (bowel).
Colonoscopy is a safe procedure that provides information other tests may not be able to give. Colonoscopy is performed by inserting a device called a colonoscope into the anus and advancing through the entire colon. The procedure generally takes between 20 minutes and one hour.
The most common reasons for colonoscopy are:
Before colonoscopy, your colon must be completely cleaned out so that the doctor can see any abnormal areas. This is vitally important to increase the chances that your doctor will identify abnormalities in your colon. If your colon is not completely cleaned out, the chances your doctor will miss abnormalities increases.
Your doctors or nurses will provide specific instructions about how you should prepare for your colonoscopy. Be sure to read these instructions as soon as you get them so you will know how to take the preparation and whether you need to make any changes to your medications or diet. If you have questions, call the doctor’s office in advance.
You will need to avoid solid food for at least one day before the test. You should also drink plenty of clear fluids on the day before the test. You can drink clear liquids (a liquid you can hold up to the light and see through) up to several hours before your procedure.
Avoid drinking red liquids. Your doctor may also ask you to avoid high fiber foods including seeds and nuts for the week before the procedure.
To clean the colon, you will take a strong laxative and empty your bowels. You may be asked to take the entire preparation the night before the test, or you may be asked to take it in two doses, with the second dose taken four to six hours prior to the colonoscopy.
Taking the preparation in two “split” doses may help get the colon even cleaner. This may require you to wake up early in the morning to complete the preparation. The instructions you are given will tell you how you should take the preparation.
A commonly used preparation is a 4-liter (1 gallon) solution that is purchased at the pharmacy with a prescription. There are several low-volume (2- to 3-liter) preparations on the market as well.
Some doctors prefer citrate of magnesia (magnesium citrate), a 300 mL bottle that requires no mixing and is over-the-counter. Packets of powdered laxative are available that are mixed with a smaller volume of water.Watery diarrhea is the desired result. This may occur shortly after drinking the solution or may be delayed for several hours. The end result should be diarrhea that looks like urine.
If you become nauseated or vomit while drinking the solution, call your doctor or nurse for instructions. Tips that can help with nausea and vomiting include temporarily stopping drinking the solution, walking around, and resuming drinking at a slower pace
THE COLONOSCOPY PROCEDURE
You will be given fluid and medicines through the IV line. With sedation/analgesia provided during the colonoscopy, many people sleep during the test, while others are very relaxed, comfortable, and generally not aware.
Your doctor may request an anesthesiologist give you an anesthetic, which is a stronger sedative and will put you to sleep while you are being closely monitored.
The colonoscope is a long black flexible tube, approximately the diameter of the index finger. The doctor will gently pump air or carbon dioxide and sterile water or saline through the scope into the colon to inflate it and allow the doctor to see the entire lining.
You might feel bloating or gas cramps as the air opens the colon. Try not to be embarrassed about passing this gas (it is just air), and let your doctor know if you are uncomfortable.
You may feel like you have to go to the bathroom, which is a normal feeling during the procedure.
During the procedure, the doctor might take a biopsy (small pieces of tissue) or remove polyps.
Polyps are growths of tissue that can range in size from the tip of a pen to several inches. Most polyps are benign (not cancerous). However, some polyps can become cancerous if allowed to grow for a long time. Having a polyp removed does not hurt.
Colonoscopy is a safe procedure, and complications are rare but can occur:
You should call your doctor immediately if you have any of the following: