irritable bowel syndrome

irritable bowel syndrome
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Name	Irritable bowel syndrome
Field	Gastroenterology
Symptoms	Abdominal pain, altered bowel habits
Onset	Variable
Duration	Chronic
Causes	Multifactorial
Diagnosis	Clinical
Treatment	Diet, pharmacotherapy, psychotherapy

irritable bowel syndrome is a common functional gastrointestinal disorder characterized by chronic or recurrent abdominal pain associated with altered bowel habits. It presents across diverse populations and intersects with clinical practice in gastroenterology, primary care, and behavioral medicine. Management often involves multidisciplinary strategies drawing on nutrition, pharmacology, and psychological therapies.

Signs and symptoms

Patients typically report abdominal pain, bloating, constipation, diarrhea, or alternating bowel patterns described in clinical notes from institutions such as Mayo Clinic, Cleveland Clinic, Johns Hopkins Hospital, Massachusetts General Hospital, and Mount Sinai Hospital. Symptom patterns are often documented during consultations in settings affiliated with Royal College of Physicians, American Gastroenterological Association, European Society for Neurogastroenterology and Motility, World Gastroenterology Organisation, and National Institute for Health and Care Excellence. Physicians may note symptom triggers following exposures associated with travel to World Health Organization surveillance regions, or during studies run by universities like Harvard University, Stanford University, University of Oxford, University of Cambridge, and University of California, San Francisco. Assessment tools referenced in trials from National Institutes of Health and European Medicines Agency include patient-reported outcome measures used in cohorts studied by researchers at Columbia University, Yale University, University College London, Karolinska Institutet, and University of Toronto.

Causes and pathophysiology

Etiology is multifactorial with contributions from post-infectious changes observed after outbreaks investigated by Centers for Disease Control and Prevention, European Centre for Disease Prevention and Control, Public Health England, and historical reports linked to epidemics recorded by John Snow-era public health. Mechanistic studies from laboratories affiliated with National Institute of Diabetes and Digestive and Kidney Diseases, Wellcome Trust, Max Planck Society, Institut Pasteur, and Victor Chang Cardiac Research Institute implicate gut-brain axis dysfunction studied alongside work from Sigmund Freud-influenced psychosomatic medicine, neurogastroenterology centers at Beth Israel Deaconess Medical Center, Karolinska University Hospital, Royal Free Hospital, Guy's and St Thomas' NHS Foundation Trust, and research consortia funded by European Research Council. Microbiome alterations paralleling findings from Human Microbiome Project, European Molecular Biology Laboratory, Howard Hughes Medical Institute, Sanger Institute, and Broad Institute suggest dysbiosis connected to studies by Jeffrey Gordon, Rob Knight, Ruth Ley, Martin Blaser, and Eric Alm. Immune activation and low-grade inflammation are described in papers from Imperial College London, University of Pennsylvania, Monash University, and University of Melbourne linking to work on cytokines by Anthony Fauci-era immunology networks. Motility abnormalities studied with manometry in centers including Mayo Clinic and Mount Sinai relate to research from investigators at Duke University, Vanderbilt University Medical Center, and Brigham and Women's Hospital.

Diagnosis

Diagnosis relies on clinical criteria developed through consensus meetings supported by organizations like Rome Foundation, American College of Gastroenterology, European Society of Neurogastroenterology and Motility, World Health Organization, and guideline panels convened by National Institute for Health and Care Excellence and American Gastroenterological Association. Diagnostic evaluation often includes basic laboratory testing available in systems such as Kaiser Permanente, imaging at centers like Rutherford Hospital, endoscopy services at Cleveland Clinic, and exclusion of alternative diagnoses including inflammatory bowel disease described by investigators at Mount Sinai, Johns Hopkins Hospital, and Mayo Clinic. Symptom-based algorithms from trials registered with U.S. Food and Drug Administration and European Medicines Agency are used alongside biomarkers under study at Massachusetts General Hospital, Stanford University, University of California, San Diego, and University of Chicago.

Management and treatment

Treatment strategies draw on dietary interventions popularized by practitioners at Monash University (low FODMAP diet), pharmacotherapies approved by U.S. Food and Drug Administration and European Medicines Agency and prescribed in clinics such as Cleveland Clinic and Mayo Clinic, and psychological therapies delivered by programs affiliated with Oxford Cognitive Therapy Centre, Maudsley Hospital, Johns Hopkins University, University College London, and University of Michigan. Pharmacologic agents including antispasmodics, laxatives, antidiarrheals, and neuromodulators are used following guidance from American College of Gastroenterology, British Society of Gastroenterology, Canadian Association of Gastroenterology, and trials led by investigators at Harvard Medical School, Yale School of Medicine, University of California, Los Angeles, and Columbia University. Probiotics and microbiome-targeted approaches are explored by teams at European Molecular Biology Laboratory, Broad Institute, Wellcome Trust Sanger Institute, and companies regulated by U.S. Food and Drug Administration. Psychological interventions include cognitive behavioral therapy from programs at Oxford University, mindfulness-based stress reduction from courses developed at University of Massachusetts Medical School, and gut-directed hypnotherapy evaluated at University of Manchester and Royal Bolton Hospital.

Epidemiology and risk factors

Prevalence estimates derive from population surveys conducted by agencies and institutions such as World Health Organization, Centers for Disease Control and Prevention, European Commission, National Health Service (England), Australian Institute of Health and Welfare, Statistics Canada, Office for National Statistics (UK), National Center for Health Statistics, Kaiser Permanente, and cohort studies at Framingham Heart Study-linked centers. Risk factors identified in epidemiologic literature involve female sex documented in registries like Swedish National Patient Register and Danish National Patient Registry, age patterns reported by National Institutes of Health, post-infectious onset described in outbreak reports by Centers for Disease Control and Prevention and Public Health Agency of Canada, and psychosocial stressors studied by teams at Harvard School of Public Health, Columbia University Mailman School of Public Health, Johns Hopkins Bloomberg School of Public Health, and London School of Hygiene & Tropical Medicine.

Impact and complications

IBS impacts quality of life measured in studies from World Health Organization, European Commission, National Institutes of Health, National Institute for Health and Care Excellence, and patient advocacy groups including International Foundation for Gastrointestinal Disorders, Crohn's and Colitis Foundation (comparative burden), British Dietetic Association, American Psychological Association, Mental Health Foundation, and Mind (charity). Economic costs are estimated in health economic analyses conducted by teams at Harvard Business School, London School of Economics, OECD, World Bank, and national health services such as NHS England and Medicare (United States). Complications include reduced work productivity documented in labor studies by International Labour Organization, comorbid anxiety and depression described in psychiatric cohorts at Massachusetts General Hospital and McLean Hospital, and overlapping functional disorders evaluated by researchers at Mayo Clinic and Cleveland Clinic.

Category:Gastroenterology