Irritable bowel syndrome (IBS) is a functional gastrointestinal disease with a high population prevalence. The disorder can be debilitating in some patients, whereas others may have mild or moderate symptoms. The most important single risk factors are female sex, younger age and
HHS Public AccessAuthor manuscript Nat Rev Dis Primers. Author manuscript; available in PMC 2016 August 26.
Published in final edited form as:Nat Rev Dis Primers. ; 2: 16014. doi:10.1038/nrdp.2016.14.
Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript preceding gastrointestinal infections. Clinical symptoms of IBS include abdominal pain or discomfort, stool irregularities and bloating, as well as other somatic, visceral and psychiatric comorbidities. Currently, the diagnosis of IBS is based on symptoms and the exclusion of other organic diseases, and therapy includes drug treatment of the predominant symptoms, nutrition and psychotherapy. Although the underlying pathogenesis is far from understood, aetiological factors include increased epithelial hyperpermeability, dysbiosis, inflammation, visceral hypersensitivity, epigenetics and genetics, and altered brain-gut interactions. IBS considerably affects quality of life and imposes a profound burden on patients, physicians and the health-care system. The past decade has seen remarkable progress in our understanding of functional bowel disorders such as IBS that will be summarized in this Primer.Irritable bowel syndrome (IBS) is a functional bowel disorder (that is, not associated with structural or biochemical abnormalities that are detectable with the current routine diagnostic tools) characterized by abdominal pain or discomfort, stool irregularities and bloating (BOX 1). Symptoms can be debilitating in many individuals, but may be mild or moderate in other patients. In addition, IBS is often associated with other somatic comorbidities (for example, pain syndromes, overactive bladder and migraine), psychiatric conditions (including depression and anxiety) and visceral sensitivity. The population prevalence of IBS is high (~11%) and the condition has considerable consequences for quality of life (QOL) that are comparable to other chronic diseases, such as diabetes mellitus and hepatitis.
IBS is diagnosed based on symptoms, and a distinction is made between the following subtypes of IBS: IBS with pain or discomfort and predominant constipation (IBS-C), IBS with diarrhoea (IBS-D), mixed IBS (IBS-M) and unsubtyped IBS (IBS-U) (FIG. 1).Moreover, other diseases (including other functional gastrointestinal diseases, such as functional dyspepsia and gastroesophageal reflux disease) that may cause the typical IBS symptoms should be excluded. Although a substantial proportion of patients will experience spontaneous remission over time, there is currently no treatment that cures IBS; relief of symptoms is the most that can be achieved.IBS is a multifactorial disease. Hence, the underlying pathogenesis is considered complex and the precise molecular pathophysiology is far...