Colonoscopy

Colonoscopy is a procedure that uses a long, flexible, narrow tube with a light and tiny camera on one end, called a colonoscope or scope, to look inside the rectum and entire colon. Colonoscopy can show abnormalities of the lining of the large intestine.

Some of the reasons a colonoscopy may be performed include but are not limited to:

• screening for colon cancer
• changes in bowel habits
• abdominal pain
• bleeding from the anus
• unexplained weight loss
• a family history of colon cancer

Be sure your doctor knows about any medicines you are taking. You might need to change how you take them before the test.

Your doctor will give you specific instructions. It’s important to read these carefully a few days ahead of time, since you may need to follow a special diet for at least a day before the test and to shop for supplies. If you’re not sure about any of the instructions, call the doctor’s office and go over them with the nurse.

You will probably also be told not to eat or drink anything after midnight the night before your test. If you normally take prescription medicines in the mornings, talk with your doctor or nurse about how to manage them for the day.

Because a sedative is used during the test, you’ll need to arrange for someone you know to take you home from the test.

The test itself usually takes about 30 minutes, but it may take longer if a polyp is found and removed. Before it starts, you’ll be given a sedating medicine (into a vein) to make you feel relaxed and sleepy during the procedure. For most people, this medicine makes them unaware of what’s going on and unable to remember the procedure afterward. You’ll wake up after the test is over, but might not be fully awake until later in the day.

During the test, you’ll be asked to lie on your side with a drape covering you. Your blood pressure, heart rate, and breathing rate will be monitored during and after the test. Your doctor might insert a gloved finger into the rectum to examine it before putting in the colonoscope.

The doctor will look at the inner walls of the colon as he or she slowly removes the colonoscope. If a small polyp is found, it may be removed. This is because some small polyps may become cancer over time. Removing the polyp is usually done by passing a wire loop through the colonoscope to cut the polyp from the wall of the colon with an electric current. The polyp is then sent to a lab to be checked to see if it has any areas that have changed into cancer.

If your doctor sees a larger polyp or tumor or anything else abnormal, a biopsy may be done. A small piece of tissue is taken out through the colonoscope. The tissue is checked in the lab to see if it’s cancer, a benign (non-cancerous) growth, or a result of inflammation.