Colonoscopy: what is this medical test used for?

If we hear the word colonoscopy, most people know what we are talking about, And we probably react with anxiety or discomfort to the idea that it may be necessary to perform one at some point in life.

Although it is often considered unpleasant, it is a necessary procedure for diagnosing and treating various pathologies. In this article, we will see what a colonoscopy is, what it is used for and how it is performed.

    Colonoscopy as a medical procedure

    Colonoscopy is a type of medical exploratory test or procedure in which, through the insertion of a colonoscope (a tube-shaped instrument with a microcamera at its end), it is possible to examine and assess the the condition of the patient’s colon and large intestine.

    It is a type of objective examination that allows the recognition and evaluation of the condition of a part of the digestive system and in particular excretors, in which in addition to viewing through the camera, it is possible to obtain data by performing biopsies. In some cases, colonoscopy is also performed therapeutically, as some instruments can be inserted through cavities of the colonoscope itself, which can help, among other things, to aspirate or remove foreign bodies or close small lesions.

    basic procedure

    When performing a colonoscopy, it is first of all necessary that the part of the organism to be visualized is free of material which could prevent the correct analysis of the organ. This is why items such as laxatives or enemas that allow the client to evacuate and have no feces in the colon are usually used before.

    Once this has been done, depending on the case, it may be advisable to administer an anesthetic or analgesic in order to avoid possible pain or discomfort in the patient. The doctor performs a rectal exam to check for obstructions and at the same time to dilate the anus. The device is then placed: the patient is pressed to the side and the knees bent to insert the device through the anus.

    Air is then introduced into the area to be examined to facilitate exploration, And finally this is done. Depending on what is found, if there is something strange, the doctor may decide to take samples or perform other actions.

    Finally, the device is carefully removed, in which case observations can also be made. It is common that, since the introduction of air, pain or gas appears which can even be expelled at the very moment of the extraction of the colonoscope.

    The subject usually remains under observation for a few hours until the effects of the anesthesia have worn off.


    The procedure we have indicated above is most often used. However, we can find several subtypes of colonoscopy.

    1. Conventional colonoscopy

    The most used, refers to the basic procedure described above: the colonoscope is inserted through the anus and rectum to make a tour and analysis of the interior of the colon. Conventional colonoscopy examines the entire colon

    2. Flexible sigmoidoscopy or proctosigmoidoscopy

    Like conventional colonoscopy, the colonoscope (in this case the sigmoidoscope) is used to view only part of the colon, especially its lower or sigmoid third. In this case, sedatives are usually not used.

    3. Computed tomography colonography or virtual colonoscopy

    This aspect of the colonoscopy is less annoying and invasive. Contrast measurements are administered beforehand. 1 colonoscope is introduced through the rectum but without having to enter the body for the most part: air is only introduced to facilitate observation. The images will be taken by X-ray from the outside.

    4. Colonoscopy with capsule

    This type of alternative colonoscopy is one of the newer modalities and is much less invasive than the previous ones. The patient has to swallow a small capsule with built-in microcameras that will send images to sensors placed on the patient’s abdomen (although previously they will have performed a colon cleanse in order to obtain useful images). It doesn’t need to be admitted or sedated. Once the capsule is excreted, the data obtained will be analyzed.

    What is it used for and what can it be detected?

    Although uncomfortable, this test is of utmost importance. It is currently one of the most effective ways to detect diseases such as colon cancer or polyps that can degenerate there. This extraction is also usually performed by colonoscopy. It is often performed in people over the age of fifty.

    Another common reason for its use is the study of the causes of the appearance of blood during defecation or simply bleeding from the rectum. It allows you to see its causes and detect diseases such as irritable bowel syndrome. In case of persistent pain and sudden weight loss, it is also recommended, cracks, abscesses or blockages by foreign bodies are also visible thanks to this technique.

    Colonoscopy, as we said, doesn’t just take pictures. It is also possible to take biopsies of suspicious content for further analysis or even perform procedures such as cauterization, suturing or removal.


    Although this is a very useful and necessary test, it can come with some risks.. Specifically, it can sometimes cause perforations in the colon or intestine, causing bleeding. However, this extreme only occurs in very rare cases.

    Using techniques such as virtual colonoscopy and capsule colonoscopy reduce these risks, although they may not be as effective. Other possible discomforts are the presence of abdominal pain and gas.

    Bibliographical references:

    • Lieberman, DA; Rex, DK; Winawer, SJ; Giardiello, FM; Johnson, DA and Levin, TR Guidelines for Colonoscopy Surveillance After Screening and Polypectomy: A Consensus Update by the US Multi-Society Working Group on Colorectal Cancer Gastroenterology. 2012; 143 (3): 844-857.

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