Irritable bowel syndrome (IBS)
This is one of the most common conditions affecting the gut. Individuals may have recurrent abdominal pain, often associated with variable stool form and frequency. Abdominal distension or bloating may be a feature. IBS may be worse at times of stress. Although physical examination, stool culture and blood test results are always normal in IBS, it is a functional condition, and the symptoms are absolutely genuine (but are not due to an identifiable disease process or detectable abnormality on investigation). If diarrhoea is the main problem then loperamide may be tried. In people with post-infective, diarrhoea-predominant IBS, ondansetron or colesevalam may be of some help. For individuals with moderate-severe IBS with constipation (IBS-C), there is a new treatment called linaclotide. Treating pain may be more challenging and a variety of different drugs may be tried: simple remedies such as peppermint oil capsules, alverine or mebeverine may be tried first and if unsuccessful, progressing to hyoscine butylbromide. In more severe cases, drugs affecting the levels of serotonin in the gut (and the brain), such as citalopram, may be tried. Cognitive therapy or hypnotherapy may be considered in those not keen on drugs, and also probiotics, and dietary changes (such as gluten-free low FODMAP diet) should be considered.