ABSTRACT
Irritable bowel syndrome (IBS) is characterised by the presence of abdominal pain or discomfort associated with defecation or altered bowel habits in the absence of any other disease to explain the symptoms. Symptoms such as bloating are also often present. The complexity of the pathophysiology of IBS is attested by the range of mechanisms that have been proposed. These include abnormalities in motility, visceral sensation, brain–gut interactions and psychosocial distress. More recently, evidence has emerged for altered gut immune activation, intestinal permeability and intestinal microbiome. Carefully phenotyping and characterisation of large cohorts of IBS patients across multiple centres might help identification of mechanism-based patient stratification. The severity of abdominal pain varies between mild to severe, and is usually episodic and may be cramping in nature. The diagnosis of IBS is built on symptom criteria, but the gastrointestinal tract has a limited language and symptoms may overlap with many treatable organic conditions.
