Episodic Ataxia

Episodic Ataxia (EA) encompasses seven types (EA1 through EA7) with varying symptoms. EA1 and EA2 are common, featuring myokymia, ataxia, and more. Triggers include stress, activity, and more. Treatment options include acetazolamide, carbamazepine, dalfampridine, and levetiracetam depending on the type.

Episodic Ataxia (EA) Types and Treatments:

There are seven varieties of dominantly inherited episodic ataxia (EA), called EA1 through EA7. Of those, EA1 and EA2 account for the majority of cases. EA1 is characterised by brief episodic myokymia (muscle rippling), gait unsteadiness, limb ataxia, dysarthria, nystagmus or tremor. These spells could be induced by physical activity, stress, environmental temperature, postural change, alcohol, caffeine or intercurrent illness. EA2 episodes tend to last longer than EA1. EA3 has recurrent brief attacks of vestibular ataxia, vertigo and tinnitus. EA4 has recurrent attacks of vertigo, diplopia, tinnitus and ataxia beginning in early adulthood. EA5 is usually in adolescent patients with episodic ataxia, seizure, migraine and/or hemiplegia. EA6 is identified in at least 3 family members with episodic ataxia but no seizures, migraine or alternating hemiplegia. EA7 is identified in a single family member with clinical features similar to those of EA2, with the exception that neurological examination is completely normal between attacks. (1, 2, 3)

Treatment

All EAs, with the exception of EA4, respond well to treatment with acetazolomide (250- 750 mg/day). Alternatively, Carbamazepine (100-200 mg daily) could benefit EA1. Also, EA2 responds to dalfampridine (4-aminopyridine) (5 mg three times a day). Frthermore, EA2 could benefit from levetiracetam 750 mg/ day, as an adjunctive agent. (4, 5, 6)

References

1- Bird TD. Hereditary ataxia overview. In: GeneReviews [Internet]. www.ncbi.nlm.nih.gov/ bookshelf/br.fcgi?book=gene&part=ataxias

2- Spacey S. Episodic ataxia type 2. In: GeneReviews [Internet]. www.ncbi.nlm.nih.gov/bookshelf/ br.fcgi?book=gene&part=ea2

3- Hasan SM, D'Adamo MC.. GeneReviews®, Adam MP, Ardinger HH, Pagon RA, et al. (Eds), University of Washington, Seattle, Seattle (WA) 1993. www.ncbi.nlm.nih.gov/books/NBK25442/

4- Zesiewicz TA, Wilmot G, Kuo SH, et al. Comprehensive systematic review summary: treatment of cerebellar motor dysfunction and ataxia: report of the guideline development, dissemination, and implementation subcommittee of the American Academy of Neurology. Neurology. 2018;90(10):464–471.

5-Zasorin NL, Baloh RW, Myers LB. Acetazolamide-responsive episodic ataxia syndrome. Neurology 1983; 33:1212.

6-Strupp M, Thurtell MJ, Shaikh AG, Brandt T, Zee DS, Leigh RJ. Pharmacotherapy of vestibular and ocular motor disorders, including nystagmus. J Neurol. 2011;258(7):1207–1222.