Chapter 18 - Irritable bowel syndrome

Abstract

Irritable bowel syndrome (IBS) is a prevalent, often chronic disorder of gut-brain interaction (DGBI; previously called functional gastrointestinal disorder). In clinical practice, IBS is characterized by symptoms of recurrent abdominal pain and disordered defecation. The Rome IV criteria can be used to diagnose patients with IBS for both clinical and research purposes. Patients should report symptoms of abdominal pain at least one day per week (on average) in association with a change in stool frequency or stool form, and/or a change (relief or worsening) in abdominal pain related to defecation. The etiology of IBS is complex, multifactorial, and likely differs from patient to patient. Alterations in gastrointestinal (GI) motility, changes in the visceral and central nervous system (CNS) perception and processing, abnormalities in mucosal and immune function, and alterations in the gut microbiome, among others, contribute to the development of IBS symptoms. IBS imposes a significant negative impact on both individuals and the healthcare system. Patients with IBS report a significant reduction in quality of life, while extensive testing, medications, and missed work all contribute to healthcare costs of more than $10 billion per year.