Unusual Presentation of West Nile Virus Meningitis With Cerebrospinal Fluid (CSF) Neutrophilia in a 68-Year-Old Male.

West Nile virus (WNV), a mosquito-borne flavivirus, can cause neuroinvasive disease, including meningitis, encephalitis, and acute flaccid paralysis. WNV meningitis typically presents with lymphocytosis in the cerebrospinal fluid (CSF). We report a case of a 68-year-old male who presented with dizziness, syncope, and head trauma, accompanied by headache, neck pain, and fever (102.3 °F), but without confusion or photophobia. The initial workup was unremarkable, but the lumbar puncture revealed elevated cerebrospinal fluid (CSF) opening pressure, neutrophilic pleocytosis, and increased red blood cells, protein, and glucose levels. CSF serology was positive for WNV IgM, and other infectious etiologies were excluded. This case illustrates that WNV meningitis may present with atypical CSF neutrophilic predominance, emphasizing the need to consider WNV in the differential diagnosis of meningitis, especially during mosquito season or in endemic areas, even when CSF findings are non-classical. Early recognition and diagnostic testing are essential for appropriate management.