A 62-year-old woman sought care in late summer for a 4-day history of upper respiratory tract symptoms, intermittent fevers, headache, and a 1-day history of disorientation, word-finding difficulties, and unsteady gait. Upon arrival to the emergency department, she had a witnessed seizure and was intubated because of increased lethargy. Her temperature was 39.4 °C, but she was otherwise hemodynamically stable. She had normal ophthalmoscopic examination findings and antigravity strength in all 4 extremities. Her deep tendon reflexes were brisk, but plantar responses were flexor. She had no rash. Cerebrospinal fluid analysis showed a normal glucose value, protein concentration of 82 mg/dL, and mixed pleocytosis. She had been hiking recently, but her family reported that there were no tick exposures or mosquito bites. Brain magnetic resonance imaging showed areas of T2 fluid-attenuated inversion recovery hyperintensity involving primarily the left thalamus and basal ganglia without definitive gadolinium enhancement. Both serum and cerebrospinal fluid were positive for immunoglobulin M antibodies to West Nile virus. The patient was diagnosed with West Nile virus encephalitis. After the seizure, the patient was treated with levetiracetam, and empiric antimicrobials were started for acute meningoencephalitis, along with adjunctive dexamethasone. Continuous electroencephalography was obtained because of the persistent encephalopathy and showed no evidence of subclinical seizures. The dexamethasone was stopped after 2 doses because of low suspicion for pneumococcal meningitis, and the antibiotics were discontinued after results of serum and cerebrospinal fluid cultures were negative for bacteria (48 hours). Acyclovir was stopped after the polymerase chain reaction results were negative for herpes simplex virus and varicella-zoster virus.
Cerebrospinal Fluid Neutrophilic Pleocytosis in Hospitalized West Nile virus Patients