Migraine and stroke.

The association between migraine and stroke is a dilemma for neurologists. Migraine is associated with an increased stroke risk and it is considered an independent risk factor for ischaemic stroke in a particular subgroup of patients. The pathogenesis is not known but several studies report some common biochemical mechanisms between the two diseases. A classification of migraine-related stroke that encompasses the full spectrum of the possible relationship between migraine and stroke has been proposed and it includes three main entities: coexisting stroke and migraine, stroke with clinical features of migraine, and migraine-induced stroke. The concept of migraine-induced stroke is well represented by migrainous infarction; it is described in the revised classification of the International Headache Society (IHS), and it represents the strongest demonstration of the relationship between ischaemic stroke and migraine. A very interesting common condition in stroke and migraine is patent foramen ovale (PFO) which could play a pathogenetic role in both disorders. The association between migraine and cervical artery dissection (CAD) is reported in recent studies. Migraine is more frequent in patients with CAD. This supports the hypothesis that an underlying arterial wall disease could be a predisposing condition for migraine. The neuroradiological evidence of subclinical lesions most typical in the white matter and in the posterior artery territories in patients with migraine, opens a new field of research. In conclusion the association between migraine and stroke remains conflicting. Solving the above mentioned issues is fundamental to understanding the epidemiologic, pathogenetic and clinical aspects of migraine-related stroke.