[MIM 141 500, 602 481, 607 516, 609 634]

The prevalence is estimated at 1-5/20,000. Autosomal dominant transmission of mutations of the CACNA1A (19p13), ATP1A2 (1q21-q23) or SCNA1 (2q24) genes that code for cerebral ion channels, that lead to an accumulation of K and glutamate in the synaptic clefts and so to neuronal hyperexcitability. Rare form of migraine with a motor aura. They are called familial in case of family history and sporadic when a family history is absent.

The motor deficit that precedes the headache is always associated with at least one other aura symptom: sensory, visual or speech disorder, or in 70 % of cases, basilar symptoms (dizziness, tinnitus).

The motor deficit lasts from 10 minutes to a few hours; headache starts during or after the aura and is associated with common migraine signs (nausea and vomiting, phonophobia and photophobia)

In case of severe crisis, one can observe a prolonged motor deficit, confusion, delirium with hallucinations, coma, fever or epilepsy: 50% of these cases occur before 20 years of age and may be the first manifestation of the disorder, which makes its diagnosis difficult.

In 80-90% of cases, the patient is asymptomatic between episodes; in the remaining 10-20 % of cases, there are permanent cerebellar signs (nystagmus, ataxia, dysarthria), epilepsy, or an intellectual deficit.

Two-thirds of the patients report one or more triggering factors: stress, mild head injury, or dietary factors, visual or auditory stimuli as in other migraines. Hemiplegic migraine seizures may alternate with other types of migraines.

Anesthetic implications:

avoid tryptans and nimodipine that possibly worsen the aura phase; possible epilepsy

References : 

-        Ducros A.
Migraine hémiplégique familiale et sporadique.
Revue Neurologique 2008 ; 164 : 216-24.

-        Ducros A.
Migraine hémiplégique familiale.
Encyclopédie Orphanet, mars 2008 11 pages
www.orpha.net/data/patho/Pro/fr/MigraineHemiplegiqueFamiliale-FRfrPro1031v01.pdf

Updated: December 2017