Colonoscopy is an examination that, carried out in endoscopy, allows to observe and analyze from the inside the health of the intestinal mucosa of the colon, thanks to the introduction of a probe, the colonoscope.
This probe consists of a flexible tube also equipped with optical fibers and one or more channels, through which various instruments (such as biopsy forceps and needles) can be introduced.
We speak more correctly of pancolonoscopy when the investigation is extended to the whole colon or rectosigmoidoscopy when it concerns only the terminal tract (rectum and sigma).
What is colon
The colon is the last stretch of the digestive system.
It has a tubular and humped appearance and extends for about one and a half meters in the abdominal area, from the cecum (which, by means of the ileo-ciecal valve, connects it to the small intestine) and the rectum.
It is divided into three main portions (the ascending, transverse and descending colon) and ends in the sigma, a stretch characterized by a double curve, and in the anus, its final sphincter.
Its role is fundamental: absorbing ingested fluids and electrolytes and completing the digestion of residues escaped from the intestine, allowing the elimination of waste material.
Colonoscopy: why you need it
Colonoscopy is first of all a diagnostic technique: allowing a direct view of the intestine, it allows to identify with greater precision than other tests the presence of lesions, hemorrhages, alterations that could be symptoms of any diseases.
Thanks to the introduction of specific instruments through the colonoscope, during its execution it is possible to take tissue samples (biopsies) to be subjected to further and specific analysis.
In addition, this endoscopic technique can also become therapeutic: during the execution, in fact, the doctor can remove tumor or pretumor lesions, stop any bleeding and, therefore, avoid in some cases the patient a subsequent recourse to surgery.
When colonoscopy is indicated
As also reported by the guidelines of the Federation of Digestive Diseases, colonoscopy is indicated first of all in the presence of signs and symptoms of the colorectal, which make further investigation necessary.
This is the case, for example:
– significant intestinal alterations detected during the execution of other tests (opaque enema, ultrasound, CT or MRI);
– unexplained gastrointestinal bleeding;
– significant weight loss (after excluding other causes);
– abdominal pain with no apparent cause;
– unexplained iron deficiency anemia;
– persistent and significant modifications of the alvo.
Colonoscopy is also indicated in the diagnosis and surveillance of colorectal cancer and adenomatous polyps. This tumor form, in most cases, derives from the malignant transformation of small growths considered precancerous (adenomatous polyps), due to the uncontrolled reproduction of the cells of the colon mucosa.
The underlying causes of this uncontrolled proliferation are not yet clear, but several factors are known that can increase the risk of getting sick, some of which cannot be modified, such as age (the incidence of cancer increases especially after 60 years) and familiarity (those who have a first-degree relative with colorectal cancer or intestinal polyps have a 2-3 times greater risk of getting sick in turn).
For this reason, the execution of a colonoscopy is indicated in patients with a family history of colon cancer (those who have first-degree relatives affected should perform it at least 10 years before the age of onset of the tumor in the relative or in any case after 50 years) and in cases of familial neoplastic syndromes (polyposis or not) of the colon.
Colonoscopy is also very important for the secondary prevention of colorectal cancer. For years, in fact, this type of investigation has been part of the screening program provided, in Italy, for all men and women considered at average risk for age, ie subjects between 50 and 69 years, with the aim of reducing mortality, identifying and removing any polyps in time, and / or allowing a diagnosis at a very early stage of the tumor form. At the moment, this is one of three screening programs activated by the National Health Service, along with those dedicated to the prevention of breast and cervical cancers (also known as uterine cervix).
The screening program for colorectal cancer provides in the first instance the execution of the test for the search for occult blood in the stool (polyps and tumors can bleed almost imperceptibly, leaving blood traces invisible to the naked eye) and, only in case of positive result, a colonoscopy is scheduled to verify the cause of bleeding and directly remove any polyps.
In case of endoscopic or surgical removal of adenomatous polyps (polypectomy), a colonoscopy is repeated within 3 years and after another 5 years in patients with multiple polyps or larger than one centimeter. The repetition of colonoscopy is also indicated in those who have been operated for colon cancer, as a periodic surveillance tool (after one and two years and, subsequently, every three years) to detect any recurrences in the bud.
The presence of inflammatory bowel diseases and inherited intestinal genetic diseases also increases the chances of developing colorectal cancer. For this reason, colonoscopy is indicated, for example, for periodic surveillance in patients who have been struggling with ulcerative colitis and Crohn’s disease for years.
Colonoscopy, gastroscopy or enteroscopy with videocaspula?
These are endoscopic examinations that differ in the area investigated, diagnostic purposes and, in the case of enteroscopy, also for the instruments used.
Unlike colonoscopy, gastroscopy (or esophagogastroduodenoscopy) allows you to examine the inner walls of the upper tract of the digestive system, through the introduction (from the mouth or nose) of a flexible probe called a gastroscope.
Invasive but not painful, this test is used in the diagnostic deepening of problems and anomalies affecting the upper digestive tract (celiac disease, gastroesophageal and biliary reflux, ulcers, etc.).
Otherwise, enteroscopy is performed using a disposable capsule equipped with a camera, slightly larger than a tablet. Once ingested, this microcapsule passes along the digestive system collecting images that, once examined, allow you to observe the walls of the small intestine in search of any lesions and / or abnormalities.
Contraindications
Colonoscopy is generally contraindicated in the presence of sudden and serious conditions such as fulminant colitis, severe acute diverticulitis, peritonitis and toxic megacolon (a serious complication of ulcerative colitis that consists of a sudden dilation of the colon).
Serious heart and respiratory disorders (such as severe heart failure or respiratory failure) can also be an obstacle to performing the examination.
In these cases, a possible alternative to traditional endoscopic investigation is represented by virtual colonoscopy, which allows to obtain three-dimensional images of the inside of the colon without inserting any probe. In fact, a CT scan is performed and, thanks to a specific software, the acquired images are processed by simulating a colonoscopy.
How to prepare for the exam
Colonoscopy requires to be performed with completely free bowel. This means that a simple fast is not enough, as for many other diagnostic tests, but it is necessary to follow some precise instructions in the days immediately preceding its execution.
Generally, at the time of booking, the center to which you are addressing provides a vademecum with the rules to be followed, which vary according to the number of days available before the exam and according to the time at which it will be performed. On this occasion it is good to report if you have particular characteristics (for example if you are pregnant or breastfeeding, if you are suffering from particular diseases) for which specific preparation methods can be prepared (some laxatives to be used to clean the intestine could, for example, be contraindicated).
Always at the time of booking it is necessary to make known if you take drugs: you do not have to suspend the treatment you are following, but the doctor will determine whether it is appropriate to temporarily interrupt or modify the therapy.
In most cases it is necessary to follow a special diet:
From 2-3 days before the exam | Avoid eating foods rich in fiber and waste (such as fruits, vegetables, legumes, pasta and whole grains), while you can continue to consume meat, fish, eggs and cheeses |
The day before the exam | Completely abstain from the consumption of solid foods and switch to a totally liquid diet (water, herbal teas, chamomile, coffee or tea, non-vegetable broth etc.). |
The day of the exam | Jejunum |
To ensure complete cleansing of the intestine, always the day before the colonoscopy (or sometimes even on the morning of the examination, if this is scheduled for the afternoon) it is generally expected to take specific laxatives, according to methods well indicated on the packaging of the same. Some, for example, should be dissolved in water in order to obtain 3-4 liters of purgative drink to drink within a few hours. Generally, this phase of preparation is the one that causes the most discomfort to patients, because it can also involve nausea and vomiting.
How to do colonoscopy
Colonoscopy is generally performed in conscious sedation, that is, after the administration of an intravenous sedative that is intended to relax, while leaving you alert and able to cooperate with doctors (it may be necessary to perform specific movements to promote the progression of the endoscope in the intestine).
You are made to lie on your side (usually on your left side) with your knees bent and the colonoscope is slowly introduced into the canal. To facilitate the movements of the probe and allow a better visualization of the mucosa, during the examination the air used to stretch the intestinal walls is blown into the colon (always through the colonoscope). This can result in the appearance of spasms, cramps, feeling of swelling, but generally these are limited discomforts. Pain or unbearable symptoms should be reported immediately to doctors.
The duration of the examination is not standard, because it depends on the tract of intestine to be explored (it will obviously be greater in a pancolonoscopy), the individual characteristics of the intestinal loops (the presence of adhesions can make the examination longer and more annoying) and the need to perform biopsies or small interventions, which inevitably lengthen the time.
After sedation, it is good to wait for a short period of time (a few tens of minutes) before being taken home and resting for the rest of the day.
Possible complications
Colonoscopy is a safe procedure, but, as in all medical practices, complications can rarely arise. The most common, but still rare, are accidental perforation of the intestinal wall or the appearance of bleeding, even in the following days, especially if polyps of important dimensions are removed during the examination.
Perforation may require immediate repair surgery, while bleeding is usually stopped in the bud and only rarely may require transfusions or even surgery.
Severe abdominal pain, fever or bleeding from the rectum after the procedure should be reported immediately to the team that performed the colonoscopy or, if you have already left, to the Emergency Room.
Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.
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