Irritable bowel syndrome symptoms include recurrent abdominal pain or discomfort that is associated with a change in stool frequency or form. The pain or discomfort may be relieved by defecation.
It is important to determine whether there are any potential precipitating dietary associations such as caffeine, lactose-containing foods, or fructose-containing foods.
Examination of the abdomen is usually unremarkable. There may be mild and poorly localised tenderness in the right lower quadrant and/or left lower quadrant.
The diagnosis is based on the patient's history; there are no specific diagnostic tests. If the patient has worrying symptoms or findings such as anaemia, weight loss, or fever, then these require thorough investigation.
Treatment should be individualised and is dependent on the patient's predominant symptoms.
Irritable bowel syndrome (IBS) is a chronic condition characterised by abdominal pain associated with bowel dysfunction. The pain is often relieved by defecation and is sometimes accompanied by abdominal bloating. There are no structural abnormalities to explain the pain. IBS occurs in about 15% of the adult population. The aetiology is probably multi-factorial, and evidence suggests motility, inflammatory, genetic, immune, psychological, and dietary components.
History and exam
Key diagnostic factors
- presence of risk factors
- abdominal pain
- alteration of bowel habits associated with pain
- abdominal bloating or distension
- normal examination of abdomen
Other diagnostic factors
- passage of mucus with stool
- urgency of defecation
- physical and sexual abuse
- post-traumatic stress disorder (PTSD)
- age <50 years
- female sex
- previous enteric infection
- family history
- family and job stress
1st investigations to order
Investigations to consider
- faecal occult blood test
- serologic tests for coeliac disease
- faecal calprotectin
- faecal lactoferrin
- serum C-reactive protein (CRP)
- erythrocyte sedimentation rate (ESR)
- serum fibroblast growth factor 19
- 23‐seleno‐25‐homotaurocholic acid (SeHCAT) test
- 48-hour stool collection for total bile acids
- empiric trial of bile acid binder
- hydrogen/methane breath test
- stool tests for Giardia lamblia
- plain abdominal x-ray
- flexible sigmoidoscopy
alternating constipation and diarrhoea
Ned Snyder, MD, MACP, AGAF
Professor of Medicine
Baylor College of Medicine and Marion DeBakey VA Hospital
Adjunct Professor of Medicine
University of Texas Medical Branch
NS declares that he is is a member on the board of the Kelsey Research Foundation, a non-profit organization. Kelsey Research Foundation has received and awarded private grants for the study of the microbiome in several diseases, including irritable bowel syndrome.
Douglas Drossman, MD
Professor of Medicine and Psychiatry
School of Medicine
UNC Center for Functional GI and Motility Disorders
DD declares that he has no competing interests.
Simon McLaughlin, MBBS
Department of Gastroenterology
St Mark's Hospital
SM declares that he has no competing interests.
Horace Williams, MBBS
Clinical Research Fellow
Division of Medicine
HW declares that he has no competing interests.
- Crohn's disease
- Ulcerative colitis
- Lymphocytic and collagenous colitis (microscopic colitis)
- AGA clinical practice guideline on the pharmacological management of irritable bowel syndrome with constipation
- AGA clinical practice update on the role of diet in irritable bowel syndrome: expert review
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