From Mr P. Crown, MRPharmS
SIR,-In reply to the letter from Dr M. Griffiths (PJ, May 6, p693), I would like to point out that irritable bowel syndrome can be a direct cause of migraine as a result of attack by the immune system on enterochromaffin cells in the intestine, and possibly because of a pathological state induced in similar 5HT storing cells in the kidneys. It would seem that other intestinal conditions affecting the integrity of 5HT storing cells could also produce migraine, even in the absence of IBS. I have in mind the existence of intestinal diverticuli and hernias in many migraine sufferers and the diminution of migraine attacks, both in severity and frequency, following surgical repair of these conditions.
Many migraine sufferers have an increase in frequency of attacks when the count of ragwort pollen is high, illustrating the effect of environmental conditions on them.
The effect of trigger foods has been well documented. These include chocolate and cheese, both of which are usually loaded with 5HT precursors. The initial prodromal effect of these is often a bout of constipation accompanied by abdominal discomfort. The aura or visual disturbance often follows less than an hour after ingesting these foods.
Other foods containing stimulant substances may be sufficient to trigger an attack. It is not well known that gluten-containing bread may well be the chief culprit. This boosts glutamate levels with an adverse effect on GABA receptors. The overall end point of migraine is an electrical dysfunction in the brain, in which wild swings in the electroencephalogram are seen. The condition can progress to a cerebrovascular accident or infarction of brain tissue.
It would seem that any excessive stimulation of the central nervous system can produce migraine as one of its manifestations, so migraine can be regarded as a multifactorial disorder. A contributory factor is probably the existence of lung diseases, such as emphysema, chronic obstructuve pulmonary disease or asthma, since the lungs are responsible for the destruction of 5HT.
I find that drinking copious amounts of water often aborts an attack, when in its initial stages. This usually produces both a large diuresis and a bowel movement.
What is probably happening is either the dilution and removal of noxious substances and/or some beneficial effect on enterochromaffin or pseudo-enterochromaffin cells. There has been sufficient documentation of the above mentioned phenomena. We have to look at the experience gained and work done over the centuries in overview. I believe that understanding of this condition can be achieved in the light of present knowledge.
Philip Crown
Sfat, Israel