What is colonoscopy?
Colonoscopy is a procedure used to see inside the colon and rectum. Colonoscopy can detect inflamed tissue, ulcers, and abnormal growths. The procedure is used to look for early signs of colorectal cancer and can help doctors diagnose unexplained changes in bowel habits, abdominal pain, bleeding from the anus, and weight loss.
How to Prepare for Colonoscopy
The doctor usually provides written instructions about how to prepare for colonoscopy. The process is called a bowel prep. Generally, 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
● plain coffee
● plain tea
● sports drinks, such as Gatorade
If you are on following medications, you should tell your doctor and hold for 5-7 days before procedures:
● arthritis medications
● blood thinners
● diabetes medications
● vitamins that contain iron
There are different colon preparation medications. The instruction can be downloaded as following PDF files.
You should be fasting and no thing by mouth before 5 am the day of the procedure.
Driving is not permitted for 24 hours after colonoscopy to allow the sedative time to wear off. Before the appointment, patients should make plans for a ride home.
How is colonoscopy performed?
Examination of the Large Intestine
During colonoscopy, patients lie on their left side on an examination table.
In most cases, a light sedative, and possibly pain medication, helps keep patients relaxed. Deeper sedation may be required in some cases. The doctor and medical staff monitor vital signs and attempt to make patients as comfortable as possible.
The doctor inserts a long, flexible, lighted tube called colonoscope into the anus and slowly guides it through the rectum and into the colon. The scope inflates the large intestine with air to give the doctor a better view. A small camera mounted on the scope transmits a video image from inside the large intestine to a computer screen, allowing the doctor to carefully examine the intestinal lining.
The doctor may ask the patient to move periodically so the scope can be adjusted for better viewing.
Once the scope has reached the opening to the small intestine, it is slowly withdrawn and the lining of the large intestine is carefully examined again.
Bleeding and puncture of the large intestine are possible but uncommon complications of colonoscopy.
Removal of Polyps and Biopsy
Your doctor will remove growths, called polyps, during colonoscopy and later test them in a laboratory for signs of cancer.
Polyps are benign in most time. However, most colorectal cancer begins as a polyp, so removing polyps early is an effective way to prevent cancer.
Your doctor will also take samples from abnormal-looking tissues during colonoscopy. The procedure, called a biopsy, allows the doctor to later look at the tissue with a microscope for signs of disease.
Colonoscopy usually takes 15-30 minutes. Cramping or bloating may occur during the first hour after the procedure.
The sedative takes time to completely wear off. Patients may need to remain at the clinic for 1 to 2 hours after the procedure.
Full recovery is expected by the next day. Discharge instructions should be carefully read and followed.
Patients who develop any of these rare side effects should contact their doctor immediately:
● severe abdominal pain
● bloody bowel movements