Midgut Motility Disorder

The Primary Motility Disorder of the Mid Gut (Pain, Gas, Bloat and Trapped Wind Syndrome). Although common, this variant of IBS is in our experience the most difficult to treat. It is particularly distressing for women and in this variant, abdominal pain - often right sided - and profound abdominal bloating are typical symptoms. Sufferers often feel very full after meals. Alternatively, they feel hungry but get full and bloated after not much more than a mouthful. Consequently, they often lose their appetites and some lose weight. They do not have any real disturbances of bowel action and none of their symptoms are relieved by opening their bowels or passing wind, which distinguishes them from the other two groups. Symptoms are thought to arise as a consequence of abnormal motility and sensation in the small or middle intestine. There is evidence that contents in the small intestine move slower than normal from the small intestine through the valve mechanism between the small intestine and the colon (ileocaecal valve) into the colon. This results in pooling of contents in the lower regions of the small intestine, an effect that leads to distension and pain at this site.

Location of Ileocaecal Valve

Main Symptoms

- diffuse non-localised abdominal pain or discomfort not relieved by opening bowels and not associated with disturbed bowel function.
- diffuse abdominal bloating, not restricted to the upper abdomen
- uncomfortable fullness after meals/feeling full up after eating very little
- trapped gas or wind
- nausea
- loss of appetite

We have shown that in this variant, small intestinal motility and sensation is very abnormal and that patients have normal colonic motility. We have had some success treating patients with the prokinetic agent Cisapride. Unfortunately this drug has been withdrawn recently because very rarely it causes irregularities of heart rhythm and is only available on a "named patient basis" for selected patients. The alternative prokinetic agents Maxalon and Motilium are less effective. The anti-depressant paroxetine (Seroxat) which is a selective serotonin reuptake inhibitor also promotes movement through the small or middle intestine by directly effecting motility. In our experience, this drug is sometimes effective when used at low doses (10-20mg/day) in patients with this variant of IBS.

Unquestionably the mainstays of future treatment of this variant of IBS will be based on the use of new receptor active drugs that are being developed by the pharmaceutical industry. These will be targeted specially at the action of the nerve fibres of the specialised enteric nervous system of the gut that are responsible for initiating intestinal contractility or motility and pain. One important clinical observation we have made in patients with this variant of IBS is that eating makes symptoms worse. Accordingly we advise patients to eat small frequent meals, and some patients are able to keep the quantity of food they eat below a threshold that promotes the onset of food related symptoms. Patients with this variant of IBS often consider that they are "allergic" or "sensitive" to various different food stuffs. In our opinion though, the intestines of these patients are likely to be "sensitive" to the effects of eating per se.


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Main Variants Of IBS - Midgut Motility Disorder