Anti-Adenylate Kinase 5 Encephalitis With Histologic Evidence of CNS Vasculitis.

Basic laboratory tests were normal. A brain MRI at admission (1 month after symptoms onset) showed bilateral, right predominant, mesiotemporal T2—fluid-attenuated inversion recovery (FLAIR) hyperintensity with gadolinium enhancement (figure). CSF analysis showed lymphocytic pleocytosis (120 cells/mm, 98% lymphocytes), hyperproteinorachia (1,032 mg/L), intrathecal IgG synthesis, and normal glucose and lactate levels. PCR for encephalitis, including HSV-1, was negative. Tuberculosis and Whipple disease were ruled out. Immunologic studies, CSF cytology, and flow cytometry were unremarkable.