Colonoscopy is a procedure to study the inside of the colon or large intestine. It is performed by a trained endoscopist utilizing a long thin flexible tube that provides a light source to illuminate the bowel and carries out an image to a video screen. The scope has a water channel to wash off the lens, an air channel to inflate the colon, a suction channel to remove fluid, and a working channel to allow passage of instruments to obtain tissue samples, remove polyps,etc. The colonoscope is capable of viewing the entire colon for diagnostic purposes, screening for colon cancer, as well as performing therapeutic interventions. Tissue may be sampled, small growths, or polyps, may be entirely removed, areas of persistent bleeding may be cauterized, strictured or narrowed areas may be dilated, just to name a few of the conditions that can be treated with the colonoscope.
Who is a Candidate for Colonoscopy?
Routine colonoscopy is offered for colon cancer screening for anyone over the age of 50. Certain other high risk groups may undergo screening colonoscopy at an earlier age. High risk groups include people with a family history of colon cancer, prior history of polyps, a history of inflammatory bowel disease, to name a few. Colonoscopy is often recommended to investigate specific symptoms such as blood in the stool, diarrhea, anemia, or follow up on an abnormal x-ray. As noted above, many of the conditions that are identified can actually be treated with the scope.
What Happens During the Procedure?
Colonoscopy is done in a hospital or equivalent setting. Upon arrival, you are checked in by the nurse including a brief history update and measuring vital signs i.e. heart rate and blood pressure. An intravenous line is started and monitoring equipment is set up to monitor heart rate, blood pressure, and breathing. This is just to insure your safety and comfort during the exam. Sedation is administered through the intravenous line using a combination of medicine geared to providing a pleasant and safe experience. This is not general anesthesia. You may be conscious of your surroundings and experience mild cramps or bloating during the procedure. If necessary, more medication may be administered throughout the exam. Some people opt to have a colonoscopy with no sedation at all, but you better be willing to put up with a fair amount of discomfort. The exam usually lasts for 15-20 minutes but recovery from the sedation may take two to three times longer. One should be prepared for at least a 2 hour hospital stay from start to finish. Because of the sedation no driving home from the procedure and no driving for 24 hrs. You will need to have a ride home. Results may be available immediately following the colonoscopy, but if tissue is removed, it will take several days for a final report.
How Will I Feel After the Test?
There is minimal recovery following colonoscopy. Air is used to inflate the colon, so you will feel bloated and need to expel the air. This generally occurs before leaving the hospital. There may be some mild cramping. The bulk of the recovery is from the sedation. It will take up to 24 hours to completely clear the effects of the sedatives. Therefore no driving,operating heavy machinery,or any other activity that you normally wouldn’t do while drinking alcohol. It is expected that you will be able to return to full activities on the day following the exam.
How do I Prepare for the Exam?
The bowel prep or clean out is the most important part of the exam and is the part that you have complete control over. Bowel preps are described in detail on another page. A good prep means a clean colon, and a clean colon means a more thorough exam and an easier exam. Less time will be spent cleaning out the residual stool with the scope and less air will be needed. This all translates to a quicker more comfortable exam with a speedier recovery.
What are the Risks of the Exam?
Colonscopy is an invasive procedure and carries finite risks. There is a small chance of causing an injury to the colon such as bleeding or perforation. Rarely the prep may cause some electrolyte disturbances, and the sedatives may also cause some untoward reactions such as respiratory depression or allergic reaction.
What are the Alternatives?
The colon can be studied by other techniques. Barium enema is an x-ray of the colon that provides a two dimensional image and will locate tumors , polyps, and diverticulosis. Sigmoidoscopy is a short version of the colonoscopy. It is usually done in the office without sedation and can view the lower third of the colon. CT scan is generally not a good way to examine the colon, nor is MRI, but the CT scan is useful for depicting the structures around the colon in the abdominal cavity. A new test currently under development is virtual colonoscopy which does utilize a CT scanner to reconstruct the colon. This is currently available in some centers and studies are currently underway to determine its place in diagnosis of colonic diseases.
6 Minute Educational Video “What to Expect During a Colonoscopy”
JoJo: Your Colon and You Video