The patient was a 70-year-old man seen for a two day history of headache and changes in mental status. The examination did not reveal any other conditions beyond subtle personality changes. A CSF demonstrated 419 cells/µL, normal glucose, and increased protein of 93 mg/dL. He was given antimicrobial agents for bacterial and herpetic meningitis. Two days after treatment began, he developed fever, his mental status deteriorated, and he required intubation. He was admitted to ICU when he developed left-sided weakness.
Eleven days later, WNV IgM was positive at a titer of 1:8. He was diagnosed with West Nile encephalitis. He was hospitalized for 42 days. After discharge he had residual left-sided weakness, but his mental status was normal.
