The hallmark of hemiplegic migraine is unilateral weakness that accompanies a migraine headache attack. The weakness is a manifestation of motor aura and occurs with other forms of aura that impair vision, speech, or sensation. This form of migraine with aura may occur either in families or only in one individual (sporadic).
This topic will review the pathophysiology, clinical features, diagnosis, and management of familial and sporadic hemiplegic migraine. Other aspects of migraine are discussed elsewhere. (See "Pathophysiology, clinical manifestations, and diagnosis of migraine in adults" and "Pathophysiology, clinical features, and diagnosis of migraine in children" and "Migraine with brainstem aura (basilar-type migraine)" and "Vestibular migraine".)
The primary feature that separates hemiplegic migraine from other types of migraine with aura is the presence of motor weakness as a manifestation of aura in at least some attacks. Migraine auras most often manifest as visual disturbances, but can also involve sensory, verbal, and rarely motor disturbances. Thus, hemiplegic migraine is an uncommon subtype of migraine with aura. (See "Pathophysiology, clinical manifestations, and diagnosis of migraine in adults", section on 'Migraine aura'.)
Hemiplegic migraine may be familial or sporadic, as discussed in the following section.
PATHOPHYSIOLOGY AND GENETICS
The weakness that characterizes hemiplegic migraine is a manifestation of motor aura. The aura of hemiplegic migraine is most probably caused by cortical spreading depression, a self-propagating wave of neuronal and glial depolarization that spreads across the cerebral cortex. (See "Pathophysiology, clinical manifestations, and diagnosis of migraine in adults", section on 'Cortical spreading depression'.)