Aetiology

There is no accepted aetiology of common migraine and migraine with aura.

Several theories are proposed:

Vascular theory:

• some studies e.g. PET scans of migraineurs, suggest that the aura is due to an spreading area of vascoconstriction over the brain
• there is some evidence that the headache in migraine is due to subsequent vasodilatation of blood vessels
• the association of stroke with migraine supports a vascular aetiology

Neuronal theory:

• aura are associated with spreading neuronal inhibition which does not respect vascular territories
• neuronal dysfunction could be the cause of the spreading vasoconstriction

A hypothalamic trigger may cause periodic overactivity of the trigeminal pain pathways

Familial hemiplegic migraine (2)

• new genetic data have allowed a more precise definition of Familial hemiplegic migraine than was previously possible. Specific genetic subforms have been identified: in FHM1 there are mutations in the

A family history of migraine is common, with the heritability estimated to be approximately 42% (3)

Reference:

• Russell, MB and Olesen, J. Increased familial risk and evidence of genetic factor in migraine. BMJ 1995; 311:541-543.
• Headache Classification Committee of the International Headache Society (IHS). The international classification of headache disorders, 3rd edition. Cephalalgia 2018; 38: 1-211
• Ashina M. Migraine. N Engl J Med 2020;383:1866-76. DOI: 10.1056/NEJMra1915327