Wednesday, June 12, 2013

New Frontiers in Irritable Bowel Syndrome


The management of irritable bowel syndrome may be not straightforward. Many different theories abound from what causes or contributes to this condition including stress, anxiety, foods that are eaten, or alcohol. In addition there are hundreds of therapies being offered from every field including probiotics, vitamins, naturopathy, homeopathy and acupuncture. It does not help the person suffering from this condition that there is not consensus or unanimous opinion amongst the medical profession as to the approach to IBS. Different clinicians may have quite different approaches to this common condition.

From the medical point of view, many different factors have been suggested as contributing to IBS. This includes visceral hypersensitivity ('oversensitive nerves in the gut'), and also increased intestinal permeability ('leaky gut') which may cause diarrhoea. The approach to IBS can be divided into diagnosis of IBS and management of IBS. From the point of view of diagnosis, IBS can often be diagnosed by the doctor taking a history and performing an examination if the story is typical. A classical story is alternating diarrhoea and constipation, associated with bloating and lower abdominal cramping. The diarrhoea tends to be low volume and does not occur at night. Alternatively there may be 'diarrhoea predominant' IBS or 'constipation predominant' IBS.

Your doctor may want to exclude other causes of these symptoms, especially if the story is not 'classical'. A basic panel of blood tests including full blood count, erythrocyte sedimentation rate, thyroid function tests is a reasonable start. If diarrhoea is predominant, your doctor may want to rule out other conditions such as inflammatory bowel disease, microscopic colitis, pancreatic insufficiency or small intestinal bacterial overgrowth. One investigation involves a 'colonoscopy' which is a thin tube with a camera on the end which examines the entire large bowel, however there are uncommon risks to this procedure and a colonoscopy is certainly not mandatory for all patients. Certain features that might trigger further investigations are called 'red flag' signs or symptoms and include loss of weight, diarrhoea at night, anemia (low red cell count), or elevated ESR. In addition, blood in the diarrhoea always mandates further investigation, generally with colonoscopy.

The management of patients with IBS encompasses a number of different areas and can be used in a stepwise approach. This includes dietary intervention, antispasmodics, medications to affect the nerves in the gut and other therapies. Dietary interventions are a complex area with every centre having a slightly different approach. One reasonable approach is to reduce 'resistant starches' in the diet, which can worsen symptoms and to use 'non-resistant' starches such as golden linseed instead. Meal times should be regularised, soft drinks and chewing gum should be reduced or avoided. Antispasmodics can be used if abdominal cramping is a problem and include peppermint oil, buscopan or mebeverine. Amitriptylline or SSRIs can reduce visceral hypersensitivity despite being originally designed as antidepressants. If anxiety or depression is an issue, this should be addressed with your clinician. In some patients, talking therapy such as cognitive behavioural therapy with a psychologist may be of benefit.

Note that this document is a guideline and individual treatment should be discussed with your clinician.

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