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Spectrum of Neurologic Findings in West Nile Virus Infection

Movement disorders are shown to be particularly salient features of the acute neurologic manifestations of WNV infection.

Most patients with West Nile virus (WNV) infections are asymptomatic or present with a mild fever. Fewer than 1% of infections result in neurologic manifestations, which have been described only retrospectively. In this study, WNV cases with acute neurologic manifestations were identified prospectively by community-based surveillance in Louisiana between August 1 and September 2, 2002.

Of 16 laboratory-confirmed neurologic WNV cases, 8 had encephalitis, 5 had meningitis, and 3 had acute flaccid paralysis (AFP). Movement disorders were prominent: 15 patients exhibited upper extremity tremor, 11 had features of parkinsonism, and 5 had myoclonus. All AFP patients had clinical and electrodiagnostic findings indicating spinal cord anterior-horn cell damage that produced a poliomyelitis-like syndrome (Journal Watch Infectious Diseases 2002 Oct 25). Upon follow-up 8 months later, 1 patient (with encephalitis) had died, 10 still had fatigue, 3 had myalgias, 2 had headaches, and 4 (with encephalitis) had cognitive deficits. Tremor remained in 5 patients, and parkinsonism, mostly mild, persisted in 5. No AFP patient showed improvement, and all remained wheelchair-bound.

Comment: This study emphasizes that movement disorders such as tremor, parkinsonism, and myoclonus are particularly salient features of the acute neurologic manifestations of WNV infection. These findings should lead one to anticipate that patients with meningitis will likely have a favorable prognosis, those with encephalitis a variable outcome, and those with AFP a poor outcome.

— Neil R. Blacklow, MD

Published in Journal Watch Infectious Diseases August 8, 2003

Citation(s):

Sejvar JJ et al. Neurologic manifestations and outcome of West Nile virus infection. JAMA 2003 Jul 23/30; 290:511-5.

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