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this drug has been withdrawn recently because very rarely it causes irregularities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.
IBS
ResearchUpdate.org Current Page:
Main Variants Of IBS - Midgut Motility Disorder
