Contributor: Gordon K. Klintworth
Migraine is an extremely common disorder with prevalence estimates of 5-20% in men and 15-40% in women. The first attack often occurs in the first decade of life, but in most affected individuals (>90%) it begins by 40 years of age. It is one of the causes of headache. The cause of migraine is poorly understood, but there is a strong familial predisposition. The International Headache Society separates patients with migraine into those with and without focal neurological symptoms. Migraine is classified into the following types: migraine without aura (common migraine), migraine with aura (migraine with typical aura, migraine with prolonged aura (aura>1 hour), familial hemiplegic migraine, basilar migraine, migraine aura without headache (migraine equivalent, migraine disocie), Ophthalmoplegic migraine [migraine - ophthalmoplegic], retinal migraine [migraine - retinal], childhood periodic syndrome, complications of migraine (including migrainous infarction), and migraine not fullfilling above criteria (atypical migraine). On rare occasions it has been associated with an arteriovenous malformation, intracranial tumor, or arteritis. Transient binocular visual loss (acephalic migraine, migraine accompaniments) is common. Isolated visual migraine is transient binocular loss of vision that occurs by itself. It is similar to the visual aura or prodrome of migraine. The symptoms include a transient bilateral homonymous loss of vision, scintillating bright lights or visual images that have been likened to a kaleidoscope. The episodes typically last for 10-20 minutes, but sometimes they persist for as long as 30 minutes. The differential diagnosis of migraine includes occlusovascular disease due to embolism or thrombosis and seizures. Paricularly when symptoms begin later in life transient cerebral ischemia needs to be excluded.