Colonoscopy: definition, preparation, and conduct of the examination
A colonoscopy is an examination that examines the inner lining of the entire colon (large intestine). It is indicated as part of check-ups in people with a history of colon cancer, digestive bleeding, unexplained pain, or diarrhea. Colonoscopy has been recommended for several years as part of general screening for colon cancer in anyone aged 50 or over with a positive Hemoccult test (screening for occult blood in the stool).
What is a colonoscopy?
Colonoscopy consists of exploring the inner wall of the large intestine (colon) using an endoscope (fiber optic) introduced through the anus.
The device (endoscope) consists of a flexible cable one centimeter in diameter and one meter fifty long, equipped with an optical fiber. It has a light source at one end. The most efficient uses a mini camera and is connected to a video screen. They can be equipped with tweezers to take samples for laboratory analysis. A control system allows the tip of the endoscope to rotate to aid progression following the curvatures of the intestine.
Colonoscopy is performed by a gastroenterologist doctor, most often under general anesthesia. A consultation with an anesthesiologist is therefore necessary before the colonoscopy. This consultation usually takes place about a week before the exam. You will then be prescribed a blood test to check that your blood is clotting properly.
What is colonoscopy used for?
This examination studies the internal wall (mucosa) of the large intestine to detect anomalies, take samples, visualize the entire colon, that is to say, the rectum, the sigmoid, the left colon (descending), transverse and right (ascending ). Colonoscopy is indicated in the assessments in case of family or personal history of colorectal cancer, bleeding of digestive origin, chronic diarrhea, unexplained abdominal pain …
A colonoscopy looks for polyps, the existence of cancer, diverticula, inflammation, or infection … This is the reference examination for exploring the colon because it gives very precise information. During this examination, the doctor can, if necessary, remove polyps or coagulate small lesions of blood vessels.
How to prepare for a colonoscopy?
Preparation is essential for a quality examination:
- Three days before, you will have to follow a strict diet without fibers or residues (no fruits, vegetables, or whole grains…). It limits the number of feces. A detailed list of authorized and prohibited foods will be given to you;
- The day before, you will have to drink two liters of preparation to evacuate all the feces because the colon must be completely clean;
- On the same day, be fasting, ie do not eat, drink or smoke. For hygienic reasons, shower and soap the whole body thoroughly twice using an antiseptic soap. Some medications may be stopped by your doctor. Take the rest of your usual treatment. Do not forget to bring the letter from your doctor and your prescriptions, your social security card, and your blood test results. If you didn’t do this during the pre-anesthetic consultation, state if you are allergic as well as your medical and surgical history.
How is the colonoscopy performed?
- Most often, the examination is done “on an outpatient basis”, that is to say, that the hospitalization lasts only a few hours. After reporting your arrival at reception, you will be made to wait a few moments in the waiting room. Before the exam, you will go to the locker room to undress. You may be given a tranquilizer to reduce apprehension.
- You are taken to the operating room, general anesthesia is performed. The doctor then introduces the endoscope through the anus and begins its exploration. It progresses slowly through the large intestine, visualizes it completely, and removes any suspicious lesions. A gas is insufflated into the intestine to unfold its wall and to explore every square centimeter of it. It lasts about half an hour but it can be longer depending on the technical difficulties encountered. During the examination, you will not notice anything thanks to the anesthesia. When you wake up, the exam will be over!
- After the exam, you can eat and drink normally. You will return home after a short period of observation (usually a few hours). Someone close to you must accompany you.
- Regarding the results, the doctor will give you the first comment. He will send his final report to your doctor as soon as possible. This will explain the results to you and give you the action to take.
Is colonoscopy painful?
It is not a painful examination but it is not very pleasant. The preparation for the exam is demanding but it is essential for a quality exam. It causes diarrhea for several hours until all feces are eliminated.
For anesthesia, an infusion is necessary but it is no more painful than a simple blood test. The rest of the examination including the samples is painless.
What are the risks of colonoscopy?
They are few and often not serious:
- The infusion may cause a hematoma or infection ;
- The endoscope can irritate the digestive walls. The most serious complication is the digestive perforation but it remains exceptional;
- The samples can be the source of low-abundance bleeding ;
- Anesthesia also presents risks that will be limited by the pre-anesthetic consultation with the anesthesiologist. The latter may prescribe additional examinations such as a chest X-ray, an electrocardiogram, or other blood tests if he deems it necessary;
- In the following days if pain, hemorrhagic vomiting, or fever occur, consult your doctor quickly.