A riddle wrapped in a mystery inside an enigma.Winston Churchill
The stroke–migraine interaction is one of the most fascinating and intriguing among neurological diseases. It appears obvious; however, it remains unravelled.
The coexistence of headache and stroke encompasses a large spectrum of possibilities including stroke caused by migraine headache, migraine developing after a stroke and non-migraine headache occurring in relation to stroke.
Headache occurs in approximately 200000 of the 550000 patients who have a stroke annually in the US (Vestergaard et al., 1993). Although not frequent, the bidirectional association between migraine and stroke is well known and important to recognize for diagnostic, treatment and prognostic reasons. Despite recent and significant advances in understanding of the pathophysiology linking both processes, the exact mechanisms relating migraine and stroke have not been fully elucidated.
When referring to migraine, we should think of a complex syndrome with many characteristics among which headache is the most prominent and is almost invariably – but not always – present. Migraine and stroke can result in focal sequelae and both share headache as a frequent symptom.
All the potential scenarios in the headache–stroke relationship include: (i) patients with history of migraine who at one point in their lives develop a stroke (temporally unrelated to migraine); (ii) patients with migraine who develop brain infarction during a typical migraine attack; (iii) patients who develop migraine immediately after a stroke; (iv) patients who develop migraine some time after having a stroke; (v) patients with migraine as a manifestation of vascular disease (thrombosis, vascular malformation) without the occurrence of a stroke; (vi) patients in whom migraine disappears after stroke occurrence; (vii) patients with non-migrainous headache only present at the time of a stroke; (viii) patients with non-migrainous headache following a stroke.