A 67-year-old woman with acute onset of fever, disorientation, and confusion was transferred to our emergency department. Physical findings revealed neck stiffness, left dominant tremulous arms with cogwheel rigidity of her extremities. Computed tomography showed mild atrophy without cerebral bleedings. Magnetic resonance imaging (MRI) with fluid-attenuated inversion recovery (FLAIR) sequence was shown in Figure (Fig. 1. on day 2, and Fig. 2. on day 5). What is the diagnosis?
