Movement Disorders in West Nile Virus Infection: A Systematic Review of Reported Cases and Conference Abstracts.

BACKGROUND

West Nile virus is the most widely distributed arbovirus and an established cause of neuroinvasive disease. While encephalitis and acute flaccid paralysis are well characterized, the spectrum of associated movement disorders remains insufficiently defined. Similar syndromes are common in Japanese encephalitis and dengue, but evidence in West Nile virus is fragmented.

OBJECTIVES

This review aimed to analyze individual patient data on movement disorders, outlining their clinical features, neuroimaging, treatments, outcomes, and underlying mechanisms.

METHODS

This review followed PRISMA guidelines, with protocol preregistered in PROSPERO. PubMed, Embase, Scopus, and Google Scholar were searched without date or language restrictions. Case reports and conference abstracts with individual patient data were eligible. Two reviewers independently screened and extracted data. Methodological quality was assessed using the Murad tool.

RESULTS

A total of 61 patients were identified, including 29 from 27 conference abstracts and 32 from 28 published reports. Opsoclonus-myoclonus, often with ataxia, was the most frequent phenotype (25/61, 41.0%), followed by tremor (11/61, 18.0%) and parkinsonism (10/61, 16.4%). Less common were isolated ataxia, chorea, dystonia, and rigidity-like syndromes. Imaging was normal in 26/61 (42.6%); when abnormal, lesions most often involved the basal ganglia or thalamus (14/61, 23.0%). Supportive care alone was provided in 28/61 (45.9%), while immunotherapies were used in 21/61 (34.4%). Outcomes were favorable in most, with complete recovery in 19/61 (31.1%) and partial recovery in 27/61 (44.3%).

CONCLUSIONS

Movement disorders, especially opsoclonus myoclonus syndrome, are significant but under-recognized manifestations of West Nile brain infection. Pathogenesis involves viral neurotropism and immune mechanisms.