|Other names||Familial or sporadic hemiplegic migraine|
|Hemiplegic migraine is inherited via autosomal dominant manner|
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Hemiplegia (Greek 'hemi' = Half), is condition that affects one side of the body. Signs of a hemiplegic migraine attack are similar to what would be presented in a stroke that typically includes sudden severe headache on one side of the brain, weakness of half the body, ataxia and aphasia which can last for hours, days or weeks. 
The ICHD classification and diagnosis of migraine distinguish 6 subtypes of hemiplegic migraine. Familial hemiplegic migraine (FHM) can be loosely divided into two categories: with and without cerebellar signs. Cerebellar signs refer to ataxia, sometimes episodic and other times progressive, that can accompany FHM1 mutations and is caused by degeneration of the cerebellum. These cerebellar signs result in a phenotypic overlap between FHM and both episodic ataxia and spinocerebellar ataxia. This is unsurprising as subtypes of these disorders (FHM1, EA2 and SCA6) are allelic, i.e., they result from mutations in the same gene. The other forms of FHM seem to be distinguishable only on the basis of their genetic cause.
Familial hemiplegic migraine
Familial hemiplegic migraine is a form of hemiplegic migraine headache that runs in families.
Sporadic hemiplegic migraine
There are also non-familial cases of hemiplegic migraine, termed sporadic hemiplegic migraine. These cases seem to have the same causes as the familial cases and represent de novo mutations. Sporadic cases are also clinically identical to familial cases with the exception of a lack of family history of attacks.
Prenatal screening is not typically done for FHM, however it may be performed if requested. As penetrance is high, individuals found to carry mutations should be expected to develop signs of FHM at some point in life.
See the equivalent section in the main migraine article.
People with FHM are encouraged to avoid activities that may trigger their attacks. Minor head trauma is a common attack precipitant, so FHM sufferers should avoid contact sports. Acetazolamide or standard drugs are often used to treat attacks, though those leading to vasoconstriction should be avoided due to the risk of stroke.
Migraine itself is a very common disorder, occurring in 15–20% of the population. Hemiplegic migraine, be it familial or spontaneous, is less prevalent, 0.01% prevalence according to one report. Women are three times more likely to be affected than males.
- RESERVED, INSERM US14 -- ALL RIGHTS. of diseases=Familial-or-sporadic-hemiplegic-migraine&title=Familial-or-sporadic-hemiplegic-migraine&search=Disease_Search_Simple "Orphanet: Familial or sporadic hemiplegic migraine" Check
|url=value (help). www.orpha.net. Retrieved 20 July 2017.
- "What is hemiplegia? | HemiHelp: for children and young people with hemiplegia (hemiparesis)". www.hemihelp.org.uk. Retrieved 2019-07-09.
- Website The International Classification of Headache Disorders 3rd edition (Beta version). Retrieved 29. August 2016.
- "familial hemiplegic migraine". Genetics Home Reference. Genetics Home Reference. Retrieved 19 June 2017.
- "sporadic hemiplegic migraine". Genetics Home Reference. Genetics Home Reference. Retrieved 19 June 2017.
- Lykke Thomsen, L; Kirchmann Eriksen, M; Faerch Romer, S; Andersen, I; Ostergaard, E; Keiding, N; Olesen, J; Russell, MB (June 2002). "An epidemiological survey of hemiplegic migraine". Cephalalgia. 22 (5): 361–375. doi:10.1046/j.1468-2982.2002.00371.x. PMID 12110112. S2CID 22040734.