Definition of migraine
Migraine
A migraine is a headache (headache) especially. Migraine pain meets specific criteria according to the classification updated in 2005 by the International Headache Society. It is a painful crisis moderate to severe recurrent unilateral pulsatile.
It may be the only disease (primary headache), or be caused by another disease (secondary headache). Only migraine primary headache is described here.
We distinguish two subtypes: migraine without aura and migraine with aura. Aura is a sign transient neurological, premonitory migraine attack. Sometimes will persist during the crisis as it occurs rarely after. Its neurological manifestations are varied. Most often it is visual tasks, language disorders, but can be observed eg olfactory hallucinations or uncontrollable yawns.
The challenges of migraine
The average prevalence of migraine on life is 18% and the mean estimated prevalence of one year is 13%. Migraines with aura are 20 to 30% of migraines, according to the International Association for Study of Pain (IASP, 2011).
According to a Swiss cohort (Merikangas et al. BMJ. 2011; 343: d5076), the annual prevalence of migraine was 0.9% (2.8 women for every man), and that of migraine without aura 10.9% (2.2 women for every man). The cumulative prevalence in 30 years is 3% for migraine with aura, 36% for migraine without aura, with a clear tendency to the persistence of crises according to the initial course 69% of migraineurs.
Migraineurs suffer an average of 25 days per year. For WHO, health weight is higher than the epilepsy worldwide. For Gustavsson et al. (Eur Neuropsychopharmacol. 2011 21: 718-79), the annual cost European headaches in general is 285 euros per person.
It does not seem that migraine increases the risk of death in general, but perhaps cardiac risk (schurks et al. Cephalalgia. September 2011, 31 (12) :1301-14).
Nearly half of patients can be treated on its own. This self-medication poses a risk of drug abuse, the consequence of which is the installation of chronic daily headache, or more than 15 days per month.
Causes and mechanisms of migraine
Migraine is caused by a double vascular phenomenon. First, a vaso-spasm, ie closure of the cerebral vessels, which can cause neurological disorders of the aura, then a reactive vasodilation resulting cerebral edema responsible for pain and general physical reactions: gastrointestinal (nausea, vomiting), ophthalmic (refusal of light).
The initial spasm is often triggered by emotions, overwork and stress, whose influence varies from one to another migraine. The female hormonal cycle is causing catamenial migraines say.
Assets foods on blood vessels are at risk of migraine in susceptible individuals: chocolate, alcohol. Coffee has paradoxical effects: it maintains a cycle "infernal" by tightening too fast veins, causing spasm, which is the source of a new expansion reaction.
The family factor is proved but only a few genes are identified formally, as in familial hemiplegic migraine. These genes encode proteins transporting ions through the membrane of neurons. Therefore suspected disorder of brain excitability, an intricate physiological relationship between migraine and epilepsy.
There are "migralepsies" where a migrainous aura triggers epilepsy. There are migraines with "invasive cortical depression" (electrical) to support this hypothesis. Disorders of subcortical inhibition and / or dysfunction of interneurons (inhibitory or excitatory) are considered cortical (Belcastro et al. J Headache Pain. 2011, 12 :289-294).
Recently Chasman et al. (Nat Genet. 2011 Jun 12; 43 (7) :695-8) revealed seven polymorphisms potentially associated with migraine with or without aura (genetic polymorphism is non-pathological variation of a gene). Three are already validated: that is to say a person is carrying more likely to migraines than the general population.
Symptoms of migraine
Headache is the typical symptom of migraine. According to the classification of the International Headache Society, migraine is a crisis for 4 to 72 hours.
The pain must behaved two of the following criteria: unilateral (that is to say, one side of the head), pulsatility, moderate or severe intensity, aggravation by routine physical activities, such as raising or lowering of stairs.
At least one of these general signs accompanying nausea / vomiting, refusal to light (photophobia), refusing even small noises (sonophobie).
Migraine with aura is less common than migraine without aura. Auras are premonitory neurologic signs and transient, mostly visual: bright spots, distorted vision ... Auras aphasia (loss of words) also exist and are rarely isolated.
You can have a variety of more or less get behavioral and psychiatric disorders (depression, apathy sudden). They may be disturbing the first time. The occurrence of typical migraine in one hour you can correct diagnosis.
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