Neurologic manifestations and outcome of West Nile virus infection.

CONTEXT The neurologic manifestations, laboratory findings, and outcome of patients with West Nile virus (WNV) infection have not been prospectively characterized. OBJECTIVE To describe prospectively the clinical and laboratory features and long-term outcome of patients with neurologic manifestations of WNV infection. DESIGN, SETTING, AND PARTICIPANTS From August 1 to September 2, 2002, a community-based, prospective case series was conducted in St Tammany Parish, La. Standardized clinical data were collected on patients with suspected WNV infection. Confirmed WNV-seropositive patients were reassessed at 8 months. MAIN OUTCOME MEASURES Clinical, neurologic, and laboratory features at initial presentation, and long-term neurologic outcome. RESULTS Sixteen (37%) of 39 suspected cases had antibodies against WNV; 5 had meningitis, 8 had encephalitis, and 3 had poliomyelitis-like acute flaccid paralysis. Movement disorders, including tremor (15 [94%]), myoclonus (5 [31%]), and parkinsonism (11 [69%]), were common among WNV-seropositive patients. One patient died. At 8-month follow-up, fatigue, headache, and myalgias were persistent symptoms; gait and movement disorders persisted in 6 patients. Patients with WNV meningitis or encephalitis had favorable outcomes, although patients with acute flaccid paralysis did not recover limb strength. CONCLUSIONS Movement disorders, including tremor, myoclonus, and parkinsonism, may be present during acute illness with WNV infection. Some patients with WNV infection and meningitis or encephalitis ultimately may have good long-term outcome, although an irreversible poliomyelitis-like syndrome may result.