Health Guide

A colonoscopy is a medical procedure that uses a long, thin tube with a tiny camera at the tip to visually examine the large intestine. It’s used as a diagnostic tool in the investigation of a wide variety of possible digestive system conditions, such as Crohn’s, ulcerative colitis, and colorectal cancers.

The procedure actually begins several days or more before the actual exam. Because fecal matter and certain fluids can obscure the view inside the colon, physicians recommend several preparatory actions.

Limiting intake to a liquid diet - clear broth or juices, tea, coffee, water and more - for a few days is a must. In some cases laxatives and/or an enema are prescribed. Fasting is a common requirement for up to 24 hours prior to the actual colonoscopy. Diabetics and others with special medical conditions are given more particular instructions.

During the exam, which may be mildly uncomfortable but can be pain-free when done correctly, the physician inserts a tube about the size of a finger through the anus and into the rectum. As the tube is moved gently upward the tiny video camera allows for a real-time visual inspection. The images are transmitted to an external monitor where they can be viewed during the exam and recorded for more careful analysis later.

The examining doctor will be on the lookout for ulcers (lesions) that are a sign of Crohn’s or other inflammatory bowel disease. Common precursors to colorectal cancer, such as the distinctive mushroom-shaped polyps that form on the lining, are also sought.

The colonoscope also has tiny scissors at the end that permit taking a tissue sample (biopsy) or for clipping off polyps, if the physician deems it warranted. They are also sometimes outfitted with a tiny laser that allows cauterizing tissue.

The procedure generally takes 20 minutes to an hour, but there are lingering effects, chiefly due to the preparatory laxatives and the sedative given just beforehand. Patients commonly feel bloated or experience flatulence afterward. Rest and relaxation, sometimes with short walks to promote passing accumulated gas, are typically recommended.

Because there is a very small risk of rupture during the exam, in part because the tube may contact polyps, ulcers, or other unhealthy tissue, bleeding is possible. A tiny amount of blood in the stool during a bowel movement shortly after is not generally cause for concern. If fever occurs or if the bleeding persists or is ample it’s advisable to seek medical attention quickly.

A colonoscopy is a highly valuable diagnostic tool but it may, and often is, only one part of a suite of tests to investigate colon disorders. Your physician may recommend, in addition, a CT scan, a barium and X-ray regime, or other procedures. Discuss your options thoroughly beforehand.