What is a Colonoscopy?
Colonoscopy is an examination that enables a careful evaluation of the lining of the colon (large intestine) for abnormalities. It is performed by inserting a colonoscope (that is constructed with a flexible tube with a camera at the end) into the anus and slowly advancing it inside the colon, as summarized in this short demonstration video of colonoscopy.
What is required to prepare for a colonoscopy?
Preparing for colonoscopy is fairly straight forward. It is helpful to follow a dietary restrictions to prepare the bowel for colonoscopy examination. In general, the colonoscopy preparation consists of consuming a large volume of a special cleansing solution and clear liquids. The colon must be completely clean for the procedure to be accurate and complete. We have recently launched a smartphone App called Colonoscopy Helper to facilitate this bowel preparation process which is available for free to download.
Can I take my current medications?
Most medications can be continued as usual, but there are some medications can cause problem during the examination. In particular, various blood thinners can cause bleeding if a polyp is found and has to be removed. You should consult your physician with a complete list of your medications and have them reviewed before proceeding with the colonoscopy preparation
You should also inform you physician if you require antibiotics prior to dental procedures, because this may also need to be prior to colonoscopy as well.
What happens during colonoscopy?
Colonoscopy is usually well-tolerated. You might feel pressure, bloating or cramping during the procedure. In general, an intravenous sedative are administered to help you relax and better tolerate any discomfort.
During the procedure, you will be asked to lie on your side or back while the instrument is slowly advanced through the large intestine. This is repeated during withdrawal. The procedure itself can take anywhere between 15 to 60 minutes, although there may be additional time necessary for waiting and recovery.
In rare cases, the examination may be difficult and a complete examination may not be technically possible. In these cases, another examination called barium enema or CT colonography might be needed.
What if the colonoscopy shows abnormality?
If an abnormality is found and further evaluation is deemed to be necessary, a sampling of tissue (biopsy) may be taken to be analyzed under the microscope. Biopsies are performed to identify various conditions including inflammation (colitis), colon polyp (an abnormal growth), or even colon cancer. If colonoscopy is being performed to identify sites of bleeding, a technique may be utilized to control the bleeding through the colonoscope by injecting medications or by coagulation (sealing off bleeding vessels with heat treatment). If a polyp is found during colonoscopy, it is often removed using a technique called polypectomy. This does not cause any pain or discomfort.
What are polyps and do they need to be removed?
Colon polyps are abnormal growths in the colon lining that are usually not cancerous. They vary in size from a tiny dimple to several inches. It is very difficult to know for certain if the polyp is benign or cancerous. Therefore, most polyps, when found, are removed and sent for analysis. Because cancer is thought to begin as a colonic polyp, its removal (polypectomy) is an important means of preventing colon cancer.
How are polyps removed?
A very tiny polyp are often removed by fulguration (burning) or by removing them with wire loops called snares or with biopsy instruments. For a large polyp, a technique called snare polypectomy is used for its removal. That technique involves passing a wire loop through the colonoscope and removing the polyp from the intestinal wall using an electrical current. There is no pain or discomfort associated with the polypectomy.
What happens after a colonoscopy?
After the procedure, it is customary for the result to be gone over after you have had chance to recover from the procedure. However, if a biopsy was performed, the result usually takes several weeks before it can be gone over.
Since sedatives are given during the procedure to make you comfortable, someone must drive you home and stay with you. Even if you feel fine and alert after the procedure, your judgment and reflexes may not be fully restored for the rest of the day. In addition, there may be some transient cramping or bloating as a result of air that was introduced into the colon during the examination.
In most cases, you should be able to eat after the examination, but this may be modified if a large polyp was removed.
What are the possible complications of colonoscopy?
Colonoscopy and polypectomy are generally very safe when performed by a qualified, fully trained, and experienced physician.One rare complication that you should be aware is a called perforation, or tear, through the bowel wall that could require surgery. Bleeding is another complication that may occur at the site of biopsy or polypectomy. Bleeding usually stops by itself, but may be persistent especially if you are on blood thinner.
Although complications after colonoscopy are extremely rare, it's important to be aware of early signs of possible complications. Contact your doctor if you notice severe abdominal pain, fever and chills, or excessive amount of bleeding.
