Migraine and cerebrovascular disease.

The association between migraine and stroke is complex and bidirectional. Epidemiological studies suggest that migraine may be a risk factor for stroke; magnetic resonance studies suggest that white matter abnormalities may be more frequent in migraine patients than in controls; and stroke may occur during the course of a migraine with aura (MA) attack (migrainous stroke). However, the relationship between migraine, aura and stroke is complex and mechanisms other than a direct cause/effect relationship are possible. Migraine aura may be the consequence, rather than the cause of cerebral ischaemia. Furthermore both MA and stroke may be secondary to a third underlying condition. In this review we analyse data regarding the relationship between migraine and stroke considering 3 aspects: (1) migraine as a risk factor for stroke, (2) migraine as a cause of stroke and (3) migraine and cerebral ischaemia sharing a common cause.