INTRODUCTION

CHRONIC INFLAMMATORY BOWEL DISEASES

Internationally known as Inflammatory Bowel Diseases (IBD), they include ulcerative colitis, Crohn's disease and the so-called "undetermined colitis".

Chronic Inflammatory Bowel Diseases have a prevalence between 1 and 1,5 cases per 1.000 people, while the incidence is 7-10 new cases/100.000 people. They can occur at any age, more frequently in patients being 15 to 30 years old and in those being 50 to 70 years old, being more common in the Countries of northern Europe. In recent years, there has been a notable increase in the incidence of chronic inflammatory bowel diseases even in the Mediterranean Europe, probably due to changes in eating habits. Also, cases of IBD with pediatric onset are gradually increasing. 25% of new patients is under 20, even if cases with early onset are found, even in the first years of life.

The clinical framework of Chronic Inflammatory Bowel Diseases is extremely variable, also expressing itself in mild forms with scarce symptoms. Sometimes the absence of clear symptoms does not allow an immediate recognition of the pathology. The main feature of Chronic Inflammatory Bowel Diseases is the presence of a chronic inflammation of the intestinal mucosa that has an intermittent course and may cause severe complications.

Both Crohn's disease and ulcerative colitis are chronic or recurrent diseases, which occur with periods of latency alternating with phases of exacerbation. The symptoms that characterize Crohn's disease and ulcerative colitis are generally very different: in most cases, Crohn's disease in fact appeared initially with diarrhea and abdominal pains, especially in the lower right part of the abdomen, which corresponds to the intestine in which the disease is most frequently located. Ulcerative colitis, on the other hand, almost always occurs with diarrhea and the presence of blood and mucus in the stool, which is often associated with a feeling of incomplete evacuation and anemia. During the stages of acute inflammatory bowel disease - both Crohn's disease and ulcerative colitis - general illness may occur such as weight loss, fatigue, inappetence, fever.

Given the non-specificity of symptoms, a correct diagnostic approach to diarrhea and/or chronic abdominal pain by the gastroenterologist is a problem as common as it is complex. The recent availability of calprotectin dosage, a specific non-invasive marker that allows to discriminate a person with an organic pathology from one with a functional disorder, has certainly allowed an important step forward in the laboratory diagnosis of chronic inflammatory bowel diseases. In fact, subjects affected by IBD have usually higher calprotectin values than both healthy subjects and those suffering from Irritable Bowel Syndrome (IBS). In the latter patients, however, the values of calprotectin can be positioned slightly above the normal limit.

The use of calprotectin as a non-invasive marker of inflammation of the intestinal mucosa is not limited only to the laboratory diagnosis phase of IBD, but is also used in the follow-up and monitoring of specific patient therapies. Calprotectin is indeed a very useful support for the differential diagnosis between organic and functional disease.

Chronic Inflammatory Bowel Diseases have an intermittent clinical and symptomatic course. The patient alternates periods in which he/she does not show the symptoms of the disease (normal alva, no abdominal pain) to others in which the disease resumes, sometimes in a more severe form. Over time Crohn's disease can involve complications such as narrowing of the lumen of the intestinal tract affected by inflammation and, in the most extreme cases, intestinal obstruction. Fistula formations or abscesses can then occur. In the case, instead, of ulcerative colitis, they can derive complications like dilatation of the colon and neoplasia.

In subjects affected by chronic inflammatory bowel diseases, other diseases can appear, affecting skin, liver and eyes.