La colonscopia: perchè farla, a che età, ogni quanto, come prepararsi

Colonoscopy is an endoscopic examination that allows the doctor to examine the internal surface of the colon. The instrument used to perform this examination is a fiberoptic endoscope, specifically designed for the organ in question, called a colonoscope, a long, thin, and flexible tube. Its standard diameter is 13 millimeters. The image is transmitted to the operator's eye by a bundle of optical fibers, or in modern videoendoscopes, a microcamera and a light source are placed at the top of the instrument. The device is long enough to allow observation of the entire colon and even a portion of the small intestine. However, this extensive examination is not always necessary: ​​examining the left part of the colon (i.e., the rectosigmoid) may be sufficient. In this case, it is called rectosigmoidoscopy. Colonoscopy can provide a direct view of the large intestine, with precision and detail far superior to a radiological examination (with the added advantage of not exposing the patient to X-rays). Furthermore, various surgical probes can pass through the endoscopic tube, which can be swapped out at will during the colonoscopy session without having to remove the main apparatus. Forceps, catheters with injection needles, snares, suture scissors, dilators, electrocoagulation probes, and recovery baskets are used. These surgical instruments allow the doctor to instantly and painlessly remove fragments of the colonic mucosa, stem any bleeding, and—crucially—remove small tumor-like lesions, such as polyps. Before performing the exam, it is necessary to scrupulously follow a set of instructions provided by the doctor. First, it is essential to ensure adequate cleansing of the intestine, which is essential for optimal observation. The patient must therefore maintain a low-residue diet for the four days preceding the test (therefore, fruit, vegetables, and foods high in fiber are prohibited) and undergo a laxative cleansing treatment (ingesting a sufficient amount of purgative to induce loose stools). Eating must also be avoided for 8-10 hours before the test. In fact, the presence of fecal material inside the colonic tube risks limiting the colonoscope's field of view. It is also crucial to provide the doctor with a list of all medications you are taking (especially aspirin and anticoagulants). The specialist may administer antispasmodics and sedatives, both to reduce contractions of the colonic walls and to limit the patient's reactivity. HOW IS IT PERFORMED? The patient is asked to sit on a bed, lying on their left side. The exam is usually performed under conscious sedation with the administration of hypnotic and antispasmodic anxiolytics to minimize discomfort. The instrument is gently inserted through the previously explored and lubricated anus. During the exam, a small amount of air may be inhaled to properly distend the intestinal walls and thus obtain an optimal view. This maneuver may cause some discomfort, the sensation of having to "defeat," and abdominal swelling that may be somewhat painful. These sensations are tolerable, but should be reported to the operator so they can adjust accordingly. The exam lasts approximately 15-30 minutes.