Neuroinvasive Powassan Virus Infection: A Case Series Highlighting Diagnostic and Clinical Challenges
Ruaa Alsaeed1, Nishitha Bujala1, Mehriban Sariyeva1, Yakira Mishan1, Hongshik Park2, Kushal Gautam1, Marc El Khoury1, Carolin Dohle1
1Westchester Medical Center, 2New York Medical College
Objective:
To characterize the clinical presentations, diagnostic findings, management approach and outcomes of neuroinvasive Powassan virus (POWV) infection especially in adults residing in endemic regions, and to highlight the diagnostic challenges and outcome associated with this emerging tick-borne encephalitis.
Background:
Powassan virus (POWV) is an emerging tick-borne flavivirus causing severe neuroinvasive disease, with increasing incidence in the United States especially during the summer. Clinical manifestations range from meningitis to meningoencephalitis including rhombencephalitis and movement disorders, often leading to poor outcomes and mortality.
Design/Methods:
We describe three cases of adults presenting with neuroinvasive POWV infection diagnosed during the summer in the Hudson Valley of New York State. All patients presented with acute or subacute encephalopathy, focal neurological deficits, and abnormal neuroimaging involving various brain regions, including the cerebellum, cortex, and subcortex. Cerebrospinal fluid (CSF) analysis consistently revealed lymphocytic pleocytosis with elevated protein and normal glucose. Diagnosis was confirmed by POWV-specific IgM in CSF or serum, with confirmatory plaque reduction neutralization testing in ambiguous cases
Results:
All patients had a prolonged hospitalization and required admission to intensive care unit. Two developed severe rhombencephalitis with rapid neurological decline, one was immunocompromised. Management was supportive given the lack of effective antiviral therapy, outcomes were poor. One patient died, while the others had persistent severe neurological deficits at discharge. These findings are consistent with prior reports indicating a 10–20% case fatality rate and long-term sequelae in the majority of survivors.The role of corticosteroids remain unknown.
Conclusions:
POWV is a neuroinvasive disease with variable neurological manifestations and outcomes. There is no known effective antiviral therapy thus increased clinical recognition, public awareness and preventative measures are important to mitigate the impact of this emerging pathogen.
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.