What is a Colonoscopy?

by J. Jay Lu, M.D.

What is colonoscopy?

Colonoscopy is the procedure of evaluating the lining of the colon to check for medical problems such as bleeding related to inflammatory bowel disease or the presence of cancer. It is the method of choice for screening patients at high risk for IBD and colon cancer. It utilizes colonoscope, a long flexible tubular instrument which is inserted into the rectum. The other end has video visualization capability to enabling the physician to inspect the lining of the colon directly. Other instruments, such as biopsy forceps can be passed through the colonoscope to perform certain surgical procedures.

Before the Procedure

Colonoscopy can be performed in a hospital or an ambulatory surgical center. The patient is given instructions before the colonoscopy. It is very important to follow the instructions carefully. The colon must be completely clean for a successful test.

In general, do not eat or drink anything for at least 8 hours before the colonoscopy. A clear liquid diet is required the day before the exam.

A liquid bowel stimulant is taken a day before the procedure to cleanse out the colon. Let the physician know about any medication or supplements you are taking. Also remind the doctor of any medication allergies you may have.

During the Procedure

Colonoscopy is well tolerated and painless. The procedure is usually done under sedation. General anesthesia (putting a patient to sleep) is usually not required. Intravenous medications are given to help you relax.

The physician will generally start with a digital rectal examination. The colonoscope is then inserted into the anus and slowly advanced into the large intestine. There might be a feeling of bloating, cramping, or pressure during the advancing of the scope.

As the scope is slowly advanced, inspection of the lining of the colon is done by the physician. If there is abnormality in the lining, the doctor may take a biopsy from the abnormal area. If colon polyps are found, they could be removed during the procedure. Specimens are then sent to the Pathology Department for evaluation.

The procedure usually takes 30 to 60 minutes.

After the Procedure

The patient will be monitored in the recovery room until he/she is stable. Occasionally, the patient may have bloating or cramping. These minor symptoms generally disappear spontaneously in a day or two. However, the doctor should be informed immediately if there is severe abdominal pain or bleeding through the rectum.

It takes about 2-3 days for the Pathologist to evaluate the specimens taken during the procedure.

It is recommended that the patient should rest for the remainder of the day. The patient should not drive within 24 hours. It is also recommended that the patient not make legal decisions until he/she is completely awake and oriented.

Complications of Colonoscopy

Colonoscopy is a very safe procedure. Severe complications are rare. One possible complication is a perforation of the bowel wall that may require surgical repair. If the physician takes a biopsy or removes a polyp, there might be bleeding at the site of the procedure. The bleeding is generally minor and stops spontaneously.

© J. Jay Lu, MD


Dr. J. Jay Lu was founder of OnTumor.com, an online resource on cancer.