Hemichorea as a primary manifestation of varicella-zoster virus neuroinfection in a child - a case report and review of literature.

Background: Varicella is a common childhood infection caused by the varicella-zoster virus. Reactivation of latent virus within somatosensory ganglia can lead to numerous complications, including cerebral vasculitis. Inflammatory processes can alter vascular structure and lead to ischemic stroke in both the pediatric and adult population. Chorea is a rare extrapyramidal symptom which might be a result of vascular insult in the course of cerebrovascular events.

Case presentation: An 8-year old boy with a recent history of varicella presented with acute-onset choreiform movements of the right extremities. A lumbar puncture revealed the presence of varicella-zoster virus genetic material in the cerebrospinal fluid. Brain magnetic resonance imaging showed ischemic lesions affecting basal ganglia, while vascular imaging was unremarkable. A diagnosis of arterial ischemic stroke secondary to varicella-zoster vasculitis was suspected, which was later supported by exclusion of other potential causes of cerebrovascular events. After a course of acyclovir and prednisone, as well as the initiation of a long-term antiplatelet therapy, marked clinical recovery was achieved. A follow-up visit 6 months later confirmed our patient's return to his pre-stroke level of functioning.

Conclusions: Varicella remains a major cerebrovascular risk factor, particularly in the unvaccinated pediatric population. Patients with varicella-zoster vasculitis might present with various neurological deficits, including hemichorea, even when vascular imaging reveals no abnormalities. Early initiation of antiviral, steroid and antiplatelet treatment might positively impact the clinical recovery time of affected individuals, although a need for large-cohort studies assessing treatment efficacy is evident.