The colon, also known as the large intestine, is responsible for the absorption of water and some nutrients as well as the compaction of feces. Sometimes the inside of the large intestine may need to be visualized, whether it's to look for early changes associated with colon cancer or to try and identify the cause of intestinal symptoms or pain. Colonoscopies allow doctors to see the inside of the colon without making any cuts or incisions.
Purpose
A colonoscopy is a procedure in which a physician uses a small camera (a colonoscope) to look for changes in the tissue of the large intestine. A colonoscopy, according to the National Institute of Diabetes and Digestive and Kidney Disorders (NIDDK) can detect inflamed tissue as well as identify abnormal growths and ulcers (sores) in the lining of the colon.
When Ordered
One of the more common uses of a colonoscopy is to screen for early signs of colorectal cancer. Colorectal cancer typically begins with the formation of small growths called polyps, which can be seen using the colonoscope. Colonoscopes can also be used to identify the source of pain, bleeding or changes in bowel movements.
Procedure
According to the Mayo Clinic, a colonoscopy is performed by inserting a colonoscope up into the rectum where it can then be moved throughout the colon. The colonoscope is essentially a long, flexible tube with a camera at the end. Most colonoscopes have instruments that allow physicians to remove any polyps or take tissue samples for further analysis.
Preparation
In order for a colonoscopy to provide as much detail as possible, patients need to make sure their large intestine is relatively free of fecal matter. Patients are often told to follow a special diet the day before the exam that involves no solid foods or red liquids. Patients may also need to take a laxative the night before the exam or receive an enema to wash out the large intestine.
Risks
Because a colonoscopy usually involves the patient receiving a mild sedative to relax, there is the risk of an adverse reaction to this medication. Colonoscopies can cause mild tearing or damage to the lining of the intestine, as well as bleeding if a polyp or tissue sample is removed. The risks associated with a colonoscopy, however, are relatively mild.
