If we hear the word colonoscopy most of us know what is being talked about , and we probably react with some anguish or discomfort to the idea that it may be necessary to have one at some point in life.

Although it is usually considered unpleasant, it is a necessary procedure that allows for the diagnosis and treatment of various pathologies. In this article we will see what a colonoscopy is, what it is for and how it is performed.

Colonoscopy as a medical procedure

Colonoscopy is a type of medical test or screening procedure in which, through the insertion of a colonoscope (a tube-like instrument with a micro camera on the end), it is possible to examine and evaluate the condition of the patient’s colon and large intestine.

This is a type of objective examination that allows the recognition and evaluation of the state of part of the digestive system and especially of the excretory system, in which, in addition to visualization through the camera, it is possible to obtain data through the performance of biopsies. In some cases, colonoscopy is also performed therapeutically, since some instruments can be introduced through cavities in the colonoscope itself that can help, among other things, to suction or remove foreign bodies or to close small lesions.

Basic procedure

When performing a colonoscopy, first of all it is necessary that the part of the organism to be visualized is free of matter that could prevent the correct analysis of the organ. That is why elements such as laxatives or enemas are usually used beforehand to allow the client to evacuate and not have any fecal material in the colon.

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

Then air is introduced into the area to be examined in order to facilitate the scan , and finally the scan is performed. Depending on what is found, the doctor may decide to take samples or perform other actions if something strange is found.

Finally, the device is carefully removed, at which time observations can also be made. It is frequent that, since air has been introduced, some pain or gas appears that can even be expelled at the very moment of the extraction of the colonoscope.

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

Subtypes

The above procedure is the one most frequently used. However, we can find several subtypes of colonoscopy.

1. Conventional colonoscopy

The most used one, refers to the basic procedure described above: the colonoscope is introduced through the anus and rectum to make a tour and analysis of the inside of the colon. In conventional colonoscopy, the entire colon is examined

2. Flexible sigmoidoscopy or proctosigmoidoscopy

Like conventional colonoscopy, the colonoscope (in this case a sigmoidoscope) is used to view only part of the colon, namely the lower third or sigmoid. In this case, no sedatives are usually used.

3. Computerized Tomography Colonography or Virtual Colonoscopy

This aspect of colonoscopy is less troublesome and invasive. Contrast measurements are administered beforehand. A colonoscope is introduced through the rectum but without the need to go very far into the body: only air is 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 most recent modalities and is much less invasive than previous ones. The patient has to swallow a small capsule with built-in micro-cameras that will send images to sensors placed in the patient’s abdomen (although he or she will have previously performed a colon cleansing so that useful images are obtained). The patient does not need to remain in hospital or be sedated. Once the capsule has been excreted, the data obtained will be analysed.

What cases are used and what does it detect?

Although uncomfortable, this test is of fundamental importance . It is currently one of the most effective ways of detecting diseases such as colon cancer or polyps that may degenerate into it. This extraction is also usually carried out by colonoscopy. It is often performed on people over the age of 50.

Another frequent reason for its use is the study of the causes of the appearance of blood in the process of defecation or simply of bleeding from the rectum. It allows us to see its causes and detect diseases such as irritable bowel syndrome. In cases of persistent pain and sudden weight loss it is also recommended. Fissures, abscesses or blockages due to foreign bodies are also visible using this technique.

Colonoscopy, as we’ve said, doesn’t just allow for imaging. It is also possible to perform biopsies of suspicious contents for subsequent analysis or even to perform procedures such as cauterizations, sutures or removals.

Risks

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

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

Bibliographic references:

  • Lieberman, D.A.; Rex, D.K.; Winawer, S.J.; Giardiello, F.M.; Johnson, D.A. & Levin, T.R. Guidelines for colonoscopy surveillance after screening and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2012;143(3):844-857.