Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract mainly characterized by abdominal pain and alterations of the alvo (problems in defecation) in the absence of any other specific pathology that causes its symptoms. Epidemiology Although the prevalence of the disease is generally difficult to understand due to the heterogeneity of the diagnostic criteria, community studies tell us that this syndrome involves 10 to 25% of the population, differently depending on the country.
IBS is spread 1.5 to 3 times more in women and affects 50% of people under the age of 35.
The causes of IBS have not yet been clearly identified.
However it is known that among the factors potentially implicated in its genesis we can find a previous gastrointestinal infection (which causes persistent immunological alterations, ie of the immune system, and muscular and neuronal hyperreactivity of the intestinal wall), an alteration of brain neurohormonal mechanisms, a altered permeability of the intestinal mucosa and possible food intolerances.
The main physiological mechanisms underlying this functional disorder are related to the alteration of intestinal motility, to the individual’s hypersensitivity to visceral pain (pain originating from the internal organs of our body), to psychological disorders (anxiety, depression ), to the irritation of the intestinal mucosa or of the bacterial population that naturally inhabits our intestine (microbiome).
The management consists mainly in the adoption of dietary measures, of a possible psychological support aimed at improving the management of stress and, finally, of the use of symptomatic drugs.
Avoiding caffeine, alcohol and exciting drinks can help reduce anxiety and irritability of the intestinal mucosa.
Avoiding legumes, as well as lactose and fructose in patients who are already intolerant, can prevent the increase in abdominal bloating.
In some cases, the irritable bowel syndrome may also be associated with gluten intolerance even in the absence of overt celiac disease; a diet without or with a reduced amount of gluten can help improve symptoms.
Furthermore, a particular group of particularly fermentable carbohydrates (FODMAPs) present in fruits and vegetables as well as in flours and in many other foods of our diet, in particular conditions can lead to an increased bacterial proliferation which increases gas production and therefore swelling . Not being able to eliminate them completely, temporary diets can be chosen aimed at containing the ingestion of these substances.
Pharmacological treatment is mainly symptomatic and involves, in the treatment of abdominal swelling and pain, the use of antispasmodic and antidepressant drugs, while the use of fibers is not always able to reduce symptoms.
In the diarrheal form of IBS, antidiarrheal drugs reduce the frequency and increase the consistency of the stools while they have no effects on pain or abdominal distension.
From 2012 it is suggested the use of Linaclotide, an agonist of guanilate cyclase 2C (an enzyme with an important role in the secretion of fluids by intestinal mucosa cells) for the treatment of chronic constipation in IBS with predominant constipation.
Rifaximin, a locally acting antibiotic, is used in the diarrheal forms of IBS and has action on symptoms such as diarrhea, abdominal bloating and pain.