Migraine aura and Mimics

The migraine aura is a fascinating, very complex clinical manifestation. Visual symptoms are almost always present but sensory symptoms are also common. Speech, symptoms and hemiplegia seen in hemiplegic migraine are rare. The underlying phenomenon is cortical spreading depression as revealed by measurement of regional cerebral blood flow during attack. First described during attacks provoked by carotid angiography, it has later been confirmed in fMRI and PET studies. Hallmarks are that symptoms spread gradually, are positive, last 5-60 minutes and are followed by headache which may sometimes be absent. The biggest differential diagnostic problem is transient ischemic attacks. There are now unambiguous diagnostic criteria for migraine aura and for transient ischemic attacks that have been validated and allow a valid clinical differential diagnosis. Unfortunately, the aura, in contrary to migraine without aura, cannot be precipitated by drugs or external stimuli. This makes detailed prospective study difficult. Interestingly, provocation of patients with exclusively migraine with aura by nitroglycerin or CGRP results in and attack of migraine without aura, sometimes for the first time. Tonabersat is a drug that inhibits cortical spreading depression and it also reduces the number of auras in patients. Unfortunately it has never been developed as a medicine