Hemiplegic migraine is a rare form of migraine characterized by a migraine headache associated with weakness on one side of the body. A disturbance in speech and various visual complaints may also occur. This may last for days. Hemiplegic migraine can occur in families or be sporadic. The sporadic form is more common and typically presents in teenage years while the familial form can present slightly earlier.

Familial hemiplegic migraine has been associated with several genes that have improved the understanding of the pathophysiology of migraine; CACNA1A seen in type 1 is a missense mutation affecting the P/Q type calcium channel.  In type 2, there is a mutation leading to loss of function in a single allele, which results in decreasing clearance of potassium and glutamate.  In type 3, the SCN1A gene is mutated with impairment of sodium channels and persistent sodium influx into the cell. In all three, the abnormalities increase the likelihood for the development of a wave in the brain known as “cortical spreading depression.” The paralysis is often the most disabling component of the attack, and acute treatment has been difficult.  Those with these disorders are typically excluded from industry trials, so there is little safety and efficacy data available to assist the treating physician. Prevention of the attacks remains the mainstay of treatment utilizing agents such as acetazolamide, flunarizine, and other calcium channel blockers such as verapamil. Triptans and ergots are avoided because of the theoretical risk of vasoconstriction, which are otherwise the most effective treatments for migraine.  This highlights the need for further research in the management of this disabling condition.