A colonoscopy is a test which allows your gastroenterologist to look in the colon. A thin tube with a camera is inserted into the rectum. This can be done for a variety of reasons, including as routine screening for polyps and cancers. The exam is usually done under sedation and requires a bowel cleansing preparation.

What is a Colonoscopy?

Colonoscopy is an effective technique for evaluating and, in many cases, improving your digestive health. The term “colonoscopy” means looking inside the colon. It is a procedure performed by a gastroenterologist, who are well-trained and certified subspecialists.

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 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 any X-ray technique including “virtual colonoscopy”. 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. In this way, colonoscopy may help to avoid surgery or to better define what type of surgery may be required.

A shorter version of the colonoscope is called a sigmoidoscope, an instrument used to screen the lower part of the large intestine only. The colonoscope, however, is long enough to inspect all of the large intestine and even a short segment of the small intestine.

Colonoscopy is a safe and effective way to evaluate problems such as blood loss, pain, change in bowel habits, and abnormalities that may have been detected by other tests. Colonoscopy can also identify and treat active bleeding from the colon.

Colonoscopy is 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.

How Colonoscopy Works

 The colonocscope is inserted in your anus and gently guided to the cecum, the first part of your digestive tract.
 Upon reaching the cecum, your doctor can guide the colonoscope to view the entire area.
 Upon finding something suspicious, your doctor can take a biopsy.
 …or remove a polyp.

How Do I Prepare for the Procedure?

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, to your gastroenterologist. Your physician 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. You must 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 exam. It is essential that you complete this step carefully, because how well the intestine is emptied determines the success of the procedure.

Various methods can be used to help cleanse the intestine. Whatever method or combination of methods that is recommended for you, be sure to follow the instructions. And remember, you should not eat or drink anything within eight to ten hours before your colonoscopy.

You’ll be asked to sign a consent form that indicates you understand the benefits and risks of the procedure prior to the examination. If there is anything you do not understand, please ask for more information.

What Can You Expect During a Colonoscopy?

During the procedure, everything will be done to make you comfortable. Your blood pressure, pulse, and the oxygen level in your blood will be carefully monitored. Your gastroenterologist will give you a sedative medication intravenously. The medication will make you relaxed and drowsy, and you will likely not recall the examination.

Once you are sedated, your doctor will perform 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.

What are the Possible Complications from a Colonoscopy?

Although colonoscopy is a safe procedure, complications very rarely occur. These include perforation or injury to the bowel wall. Perforation is a puncture of the colon wall, which might require surgery.

When polyp removal or biopsy is performed, bleeding may result and rarely requires blood transfusion or reinsertion of the colonoscope to control the bleeding. Please discuss any specific concerns you may have about the procedure with your gastroenterologist.

Afterwards, you will be cared for in a recovery area until the effects of the medication have mostly worn off. At this time, your doctor will inform you about the results of your colonoscopy and provide any additional information. Some results, such as the results of any biopsies, may take additional time and your physician will ask you to call for these results. You’ll also be given instructions about how soon you can eat and drink plus other guidelines for resuming your normal routine.

What Can You Expect After Your Colonoscopy?

Occasionally, minor symptoms such as bloating, gas or mild cramping may persist. These symptoms should disappear in 24 hours or less. By the time you’re ready to go home, you’ll feel more alert. Nevertheless, you should rest for the remainder of the day. This means not driving, making important decisions, or operating machinery. You will need to have a family member or friend take you home.

What Kind of Findings Might be Made with the Examination?

A number of different types of pathology are possible. Much of this discussion involves considering what type of issues you were having investigated to begin with. For example, pain may be a sign of diverticulitis or inflammatory bowel disease. Diarrhea may be a sign of infectious colitis, IBS, or inflammatory bowel disease. A routine screening colonoscopy is most likely to be normal or have polyps. A poster of common GI diagnoses in graphic form can be found here:

Learn more about Colonoscopy and Potential Findings