Case of eastern equine encephalitis presenting in winter

A 50-year-old man was admitted in midwinter with fever, altered mental status and new onset generalised tonic-clonic seizure with urinary incontinence. Cerebrospinal fluid (CSF) analysis revealed an opening pressure of 14.5 cm of water, normal glucose and protein 82 mg/dL (reference range: 15-45 mg/dL). Cell count showed: red cells 11 (reference range: <5 mm(3)), white cell count 1 (reference range: <5 mm(3)). The patient's blood and CSF cultures had no growth. MRI of the brain with and without gadolinium contrast showed abnormal T2 and fluid-attenuated inversion recovery signals within bilateral ventricular nuclei, hippocampi, left frontal and parietal regions. Eastern equine encephalitis (EEE) antibody, IgG titre was 1:64 and IgM titre was <1:16. Three weeks later, his repeat/convalescent titres increased to 1:1024 and 1:32, respectively. Hence, a diagnosis of EEE was established. The patient was treated with supportive care. He recovered well with mildly impaired memory but no other cognitive deficits.