A colonoscopy is a visual examination of the entire large intestine, also known as the colon. This exam is used to explore possible causes of abdominal pain, rectal bleeding, chronic constipation, chronic diarrhea and other intestinal problems. A colonoscopy is also used a method of screening for colon cancer.
A gastroenterologist (GI) uses a lighted, flexible tube called a colonoscope that has a small video camera attached to the tip allowing the GI to view the inside of the entire colon. GIs can also remove polyps and sample abnormal-appearing tissue in the colon during a colonoscopy.
Men and women are advised to schedule regular colonoscopies starting at age 50 and continue to get a colonoscopy every 10 years to screen for colon cancer. Patients who have a family history of colon cancer or other risk factors for colon cancer should begin screening earlier.
What Are the Possible Outcomes?
If polyps are found, your doctor can remove them during the procedure. The procedure 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, and you should experience no recovery pain. Polyps are small growths in the lining of the colon that approximately 25 percent of healthy individuals develop by age 50. While the overwhelming majority of polyps are benign, your physician will have it tested, and as soon as your lab results are ready, your physician will contact you to schedule a time to confirm the results with you. Furthermore, since most colon cancer starts as a benign polyp, when these are removed, the possibility of them growing into cancer is eliminated as well.
Preparing for a Colonoscopy
Thorough cleansing of the entire bowel is essential for effective results so there will not be a need for retesting. Instructions for doing this will be given by your physician, but this can include a combination of the following: enemas, restriction from eating solid foods a day or two before the test and taking pill-form and/or liquid laxatives. The following recommendations are general guidelines, however, your physician may have varying instructions for your specific procedure. Please confirm with your physician the details of your prep instructions.
You will not be able to eat or drink the day of the procedure. You may be told to stop taking aspirin or other blood-thinning medications for several days before the test as well. Also, you should alert your doctor if you require antibiotics prior to dental procedures because this may also necessitate antibiotics before your colonoscopy.
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), and water. 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. Finally, you need to arrange for someone to drive you home afterward because lingering, subtle effects of the sedation will make it unsafe for you to drive until the next day.
Your doctor will also want to know if you have heart disease, lung disease, or any other medical condition that may need special attention.
What Happens During a Colonoscopy?
To be certain you are comfortable and relaxed, you will be given intravenous (IV) sedation. In fact, most patients are asleep during the entire process and remember little to nothing about it.
When it's time to start the examination, 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. As the colonoscope makes its way through the colon, the physician can see the lining of the colon 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 typically takes 20 minutes to an hour. When complete, your nurse will take you into a recovery area, where the sedation quickly wears off. Your physician will talk to you about your test and any findings.
What Happens After a Colonoscopy?
Depending on the type of sedation (moderate or deep) used for your procedure, it can take anywhere from 30 minutes to an hour to recover from the sedation. You will need someone to drive you home because it can take up to a day for the full effects of the sedative to wear off. You should be able to resume normal activity the next day. If a polyp was removed during your colonoscopy, your doctor may put you on a special diet temporarily.
Your doctor will go over the results with you. The results of a colonoscopy are considered either negative or positive. A negative result means that the doctor did not find any abnormalities in the colon. A positive result means that the doctor found polyps or abnormal issue in the colon. Your doctor may recommend having a follow-up colonoscopy in as little as three months depending on the size and number of polyps found. If no polyps were found, your next colonoscopy will need to be in 10 years, but it will be sooner depending on your family history and other factors.
- Stop Colon Cancer Now
- National Cancer Institute: Colorectal Cancer Screening
- Colorectal Cancer Screening: Questions and Answers
- CDC: Colorectal Cancer Screening Saves Lives (PDF)
- CDC: Colorectal Cancer Basic Facts on Screening (PDF)