Serum ferritin levels in West Nile encephalitis.

West Nile encephalitis (WNE) presents clinically as aseptic meningitis, meningoencephalitis, encephalitis, or acute flaccid paralysis. Non-specific laboratory findings, e.g., leukopenia and thrombocytopenia, accompany WNE. Lymphopenia is marked and prolonged with WNE. Three patients with WNE were found to have elevated serum ferritin levels. Severity seemed to be directly related to serum ferritin levels. Although preliminary, the results suggested that serum ferritin levels >or= 500 ng/mL (normal range 5-187 ng/mL) occur late with WNE, and not in a control group of patients with viral meningitis or encephalitis.