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Colonoscopy

A colonoscopy is a common medical procedure that is used to check for early signs of colon and rectal cancer and also to determine the cause of unexplained changes in bowel habits. During the procedure, a long, flexible camera is inserted into the rectum. If anything abnormal is seen during the procedure, like a polyp or inflamed tissue, it is removed using tiny instruments passed through the scope.

What Is a Colonoscopy?

A colonoscopy is a procedure that lets your physician look inside your entire large intestine, from the lowest part (the rectum) all the way up through the colon to the lower end of the small intestine. A colonoscopy is used to look for early signs of cancer in the colon and rectum. This procedure is also used to diagnose the causes of unexplained changes in bowel habits. A colonoscopy enables the physician to see things like:
 
  • Inflamed tissue
  • Abnormal growths
  • Ulcers
  • Bleeding.
 

What Happens During a Colonoscopy?

During a colonoscopy, you will lie on your left side on the examining table.
 You will probably be given pain medication and a mild sedative to keep you comfortable and to help you relax during the exam. Your physician will insert a long, flexible, lighted tube into your rectum and slowly guide it into your colon. The tube is called a colonoscope. The scope transmits an image of the inside of the colon so that your physician can carefully examine the lining of the colon during the colonoscopy. The scope bends so that the physician can move it around the curves of your colon. You may be asked to change position occasionally to help your physician move the scope. The scope also blows air into your colon, which inflates the colon and helps the physician see better.
 
If anything abnormal is seen in your colon during the colonoscopy, like a polyp or inflamed tissue, your physician can remove all or part of it using tiny instruments passed through the scope. The tissue is then sent to a lab for testing. If there is bleeding in the colon, the physician can pass a laser, heater probe, or electrical probe, or inject special medicines through the scope and use it to stop the bleeding.
 
After the colonoscopy, your doctor will have more information about the condition of your colon and lower digestive tract.
 
(Click Colonoscopy Procedure for more information.)
 

Possible Shortcomings and Risks of the Procedure

Colonoscopy has been done for many years, with good results. It is effective for finding problems with the lower digestive tract. However, it is possible that abnormal growths can be missed. This could be because the bowel prep was not done well or because of the placement and size of the growth. This is one reason why it is very important to tell your healthcare provider about any symptoms you may have after the colonoscopy. Bleeding and puncture of the colon (perforation) are possible complications of colonoscopy, but such complications are uncommon.
 
(Click Colonoscopy Risks for more information.)
 

How Long Does It Take?

It takes about 30 to 60 minutes to perform a colonoscopy. The sedative and pain medicine should keep you from feeling much discomfort during the exam. You will need to remain at the colonoscopy facility for 1 to 2 hours until the sedative wears off.
 
Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD
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