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 discomfort
- 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
- 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 celiac 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
- Crohn's disease
- Ulcerative colitis
- Lymphocytic and collagenous colitis (microscopic colitis)
- American Society for Gastrointestinal Endoscopy guideline on informed consent for GI endoscopic procedures
- ACG clinical guideline: management of irritable bowel syndrome
Irritable bowel syndrome: what is it?
Irritable bowel syndrome: what treatments work?More Patient leaflets
- Log in or subscribe to access all of BMJ Best Practice
Use of this content is subject to our disclaimer