What is colonoscopy?
Colonoscopy is a procedure used to see inside the colon and rectum, used to detect inflamed tissue, ulcers and abnormal growths. A colonoscopy also looks for early signs of colorectal cancer and can be used to diagnose unexplained changes in bowel habits, abdominal pain, bleeding from the anus and weight loss. It is most often used to find and remove precancerous tissue (polyps) in order to prevent colon cancer.
What are the colon and rectum?
The colon and rectum are the two parts of the large intestine; the two terms are often used interchangeably. The large intestine is also sometimes called the large bowel. Digestive waste enters the colon from the small intestine as a semisolid or liquid. As waste moves toward the anus, the colon removes moisture and forms solid stool. The rectum is about 6 inches long and connects the colon to the anus. Stool leaves the body through the anus. Muscles and nerves in the rectum and anus control bowel movements.
How do you prepare for a colonoscopy?
All solids must be emptied from the gastrointestinal tract by following a clear liquid diet for 1 to 3 days before the procedure. Patients should not drink beverages containing red or purple dye. Acceptable liquids include: fat-free bouillon or broth, strained fruit juice, water, plain coffee, plain tea, sports drinks, such as Gatorade or gelatin.
A laxative or an enema may be required the night before colonoscopy to ensure your gastrointestinal tract is emptied. Your physician will order a variety of bowel preparations designed to completely empty your colon of waste before the colonoscopy.
How is a colonoscopy performed?
During colonoscopy, patients are sedated. While lying on your left side on an examination table a long, flexible, lighted tube called a colonoscope, is inserted into the anus and slowly guided through the rectum and into the colon. The scope inflates the large intestine with air to give the doctor a better view. Images are transmitted from inside the large intestine to a computer screen, allowing the doctor to carefully examine the intestinal lining. The lower small bowel is frequently seen as well.
During a colonoscopy the doctor removes abnormal looking tissues and also removes polyps to test for signs of pre-cancer or cancer. Polyps are common in adults and are usually harmless. However, most colorectal cancer begins as a polyp, so removing polyps early is an effective way to prevent cancer.
It usually takes 30 minutes or less and cramping or bloating may occur during the first hour after the procedure. The sedative rapidly wears off. Patients may need to remain at the facility for 30 minutes after the procedure for recovery.
At what age should routine colonoscopy begin?
Routine colonoscopy should begin at age 50 for most people (45 for African Americans), earlier if there is a family history of colorectal cancer, personal history of inflammatory bowel disease, obesity, smoking or certain higher risk groups such as African Americans.