Colonoscopy is an exam that evaluates the mucosa of the large intestine, being especially indicated to identify the presence of polyps, intestinal cancer or other types of changes in the intestine, such as colitis, varicose veins or diverticular disease.
This test can be indicated when the person has symptoms that may suggest intestinal changes, such as bleeding or persistent diarrhea, for example, but it is also routinely necessary for the screening of colon cancer for people over 50, or earlier, if any an increased risk of developing the disease. Check out the symptoms of bowel cancer and when to worry.
To perform the colonoscopy, it is necessary to make a special preparation with adjustments in food and use of laxatives, so that the intestine is clean and the changes can be visualized. Generally, the test does not cause pain as it is done under sedation, however, some people may experience discomfort, swelling or pressure in the abdomen during the procedure.
What is it for
Some of the main indications for colonoscopy include:
- Search for polyps, which are small tumors, or signs suggestive of colon cancer; Identify causes of bleeding in the stool; Assess persistent diarrhea or other changes in bowel habits of unknown origin; Diagnose colon diseases such as diverticulosis, intestinal tuberculosis, ulcerative colitis or Crohn's disease, for example; Investigate causes of anemia of unknown origin; Make a more detailed assessment when changes are found in other tests such as stool occult blood testing or dubious images in the opaque enema, for example. Check out what other tests are indicated to detect bowel cancer.
During the colonoscopy exam, it is also possible to perform procedures such as biopsy collection or even the removal of polyps. In addition, the test can be indicated as a therapeutic method, since it also allows the cauterization of blood vessels that may be bleeding or even a decompression of intestinal volvulus. See what intestinal volvo is and how to treat this dangerous complication.
Preparation for colonoscopy
For the doctor to be able to perform the colonoscopy and visualize the changes, it is necessary that the colon is completely clean, that is, without any residue of feces or food and, for this, a special preparation for the examination must be done, which is indicated by the doctor or clinic that will perform the exam.
Ideally, the preparation is started at least 2 days before the exam, when the patient can start an easily digestible diet, based on bread, rice and white pasta, liquids, juices without fruit pulp, meat, fish and eggs cooked, and yogurt without fruits or pieces, avoiding milk, fruits, nuts, greens, vegetables and cereals.
In the 24 hours before the exam, a liquid diet is indicated, so that no residues are produced in the large intestine. It is also recommended to use laxatives, drink a solution based on Mannitol, a type of sugar that helps in cleaning the intestine, or even do an intestinal wash, which is done according to the doctor's guidance. Learn more about the diet and how to prepare for colonoscopy.
In addition, some of the medications used may need to be discontinued before the test, such as ASA, anticoagulants, metformin or insulin, for example, according to the doctor's recommendation. It is also necessary to go with the exam, as sedation may make the person drowsy, and driving or working after the exam is not recommended.
How colonoscopy is performed
Colonoscopy is performed with the introduction of a thin tube through the anus, usually under sedation for better patient comfort. This tube has a camera attached to it to allow visualization of the intestinal mucosa, and during the examination small amounts of air are injected into the intestine to improve visualization.
Normally, the patient is lying on his side and, while the doctor inserts the tube of the colonoscopy machine into the anus, he may experience increased abdominal pressure.
Colonoscopy usually lasts between 20 to 40 minutes and, after the exam, the patient must be in recovery for about 2 hours before returning home.
What is Virtual Colonoscopy
Virtual colonoscopy uses computed tomography to obtain images of the intestine, without the need for a colonoscope with a camera to capture images. During the examination, a tube is inserted through the anus that injects air into the intestine, facilitating the observation of its interior and possible changes.
Virtual colonoscopy has some limitations, such as difficulty in identifying small polyps and inability to perform a biopsy, which is why it is not a faithful substitute for normal colonoscopy. Read more about this procedure at: Virtual colonoscopy.
