Refers to a group of symptoms, including abdominal pain and discomfort, bloating, and change in bowel habit, for which no underlying cause or pathology can be identified
Aetiology
Onset generally <45 but persists into old age
Risk factors
Female gender (2:1)
Family history
Mental health problem e.g. anxiety
Clinical features
Symptoms
Abdominal pain often relieved by defaecation
Misbehaving bowels - constipation (IBS-C), diarrhoea (IBS-D) or mixed (IBS-M)
Signs
May be tenderness in left iliac fossa
Investigations
Diagnosis is symptom based
Bloods: used to rule out other causes, should be normal
FBC, coeliac serology, CRP, TSH
AXR: consider selectively
Rome III diagnostic criteria
Recurrent abdominal pain or discomfort at least 3 days per month in the last 3 months associated with 2 or more of the following:
Improvement with defaecation
Onset associated with change in frequency of stool
Onset associated with a change in the form of stool