Colonoscopy Overview

A colonoscopy is a visual examination of the entire large intestine (also called the colon) using a lighted, flexible colonoscope. To be certain you are comfortable and relaxed, you will be sedated through an IV. In fact, most patients are asleep during the entire process and remember little to nothing about it.

What to Expect

When it’s time to start the screening, you will be asked to lie on your side. Once sedation takes effect, the colonoscope is inserted through the rectum and moved gently around the bends of the colon, allowing the physician to see images on a television screen. Typically, the physician looks all the way to the end of the large intestine, and back, for anything unusual. The entire scoping process usually takes between 15 and 30 minutes. When complete, your nurse will take you into a recovery area, where the sedation quickly wears off.

What Can Be Found?

If very small growths of tissue called polyps are found, your doctor can perform a biopsy immediately. The biopsy involves passing an instrument through the scope to remove the polyp, which is sent to a laboratory to be analyzed.

You should feel nothing when a biopsy or polyp is taken. While the overwhelming majority of polyps are harmless, your physician will have it tested and confirm your results with you. Results are usually available within one week, depending on the day of the week of your procedure. Furthermore, since most colon cancer starts as a benign polyp, when these are removed, the chances of them growing into cancer is reduced.

What Happens Afterwards?

Once your recovery nurse determines that most of the effect of the sedation has worn off, you will be released. However, you cannot drive. Even though you will feel fine, the lingering effects of the sedation will make it dangerous for you to drive, so a responsible adult must be there to take you home. You should be able to resume normal activity the next day.

How to Prepare – Prep Instructions

A thorough cleansing of the entire bowel is essential for effective results so there will not be a need for retesting. You should follow the specific instructions given by your physician, but cleansing the bowel can include a combination of the following: enema, restriction from eating solid foods a day or two before the test, and taking pill-form and/or liquid laxatives.

To avoid dehydration, patients should drink clear, fat-free bouillon or broth, gelatin, strained fruit juice (no grape juice or any liquid with red color), water, plain and unsweetened coffee or tea, or diet soda.

You may be told to stop taking aspirin or other blood-thinning medications for several days before the test as well. Unless otherwise instructed, continue taking any regularly-prescribed medication. Your physician may ask you to stop taking iron preparations a few weeks before the test if you are on them. Your doctor will also want to know if you have heart disease, lung disease, or any medical condition that may need special attention.

Finally, you need to arrange for someone to drive you home after your procedure. The sedation will make it unsafe for you to operate a motorized vehicle until the next day.

Reasons for Colonoscopy

  • Weight loss
  • Rectal bleeding
  • Abdominal pain
  • Nausea and/or vomiting
  • Personal and/or family history of colon cancer
  • Screening

Possible Risks and Complications

A colonoscopy is generally a low-risk procedure. However, complications include but are not limited to the following:

  • Perforation: Instruments may injure the GI tract wall, with possible leakage of GI contents into the body cavity. If this occurs, hospitalization or surgery may be required.
  • Bleeding: Biopsies, removal of polyps, or dilation can cause bleeding. Managing this complication may include careful observation, hospitalization, transfusions, and/or a surgical operation.
  • Infection: Entry of stomach contents into the lungs may cause pneumonia. Infection of the heart valve may occur on rare occasions.
  • Missing: Polyps or significant tumors may be overlooked.
  • Drug Reaction: Reactions to medications received before, during or after your procedure can cause nausea, vomiting, weakness, dizziness, lightheadedness and/or loss of consciousness, skin rash, itching, shallow breathing, decreased rate or absence of breathing, cardiac rhythm changes or cardiac arrest.
  • Other Risks: Additional risks include reactions and complications from diseases you may already have. Instrument failure and death are extremely rare but remain remote possibilities.