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Irritable bowel syndrome
Background
Overview
Definition
IBS is a functional gastrointestinal disorder characterized by recurrent abdominal pain and altered bowel habits (constipation, diarrhea or both), often with associated bloating.
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Pathophysiology
The etiology of IBS is poorly understood. Potential etiological mechanisms include genetic factors (most notably an identified mutation of SCN5A); post-infectious changes, chronic infections and disturbances in the intestinal microbiota; low-grade mucosal inflammation, immune activation, and altered intestinal permeability; disordered bile salt metabolism (in 10-20% of patients with diarrhea); abnormalities in serotonin metabolism; and alterations in brain function.
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Epidemiology
In the US, the incidence of IBS is estimated at 196 cases per 100,000 person-years, with an estimated prevalence of 5-12% based on Rome II criteria.
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Disease course
Key clinical manifestations include abdominal pain or discomfort, bloating, diarrhea, and constipation.
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Prognosis and risk of recurrence
There is no evidence that IBS is associated with an increased risk of mortality. However, patients with IBS exhibit a poorer QoL and utilize the healthcare system to a greater degree than patients without the diagnosis.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of irritable bowel syndrome are prepared by our editorial team based on guidelines from the American Gastroenterological Association (AGA 2024,2022,2020,2012), the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN 2023), the United European Gastroenterology (UEG/ESPEN 2023), the American College of Gastroenterology (ACG 2021), the British Society of Gastroenterology (BSG 2021), ...
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