Review Question - QID 217198

A 35-year-old man presents to the emergency department with altered mental status. He was found by his roommate to be disoriented this morning. He had complained of a right-sided headache for the past 5 days. He has a history of human immunodeficiency virus (HIV) infection being treated with bictegravir, emtricitabine, and tenofovir. His last CD4 cell count was 500/mm^3. He does not smoke tobacco and drinks alcohol socially. His temperature is 104.2°F (40.1°C), blood pressure is 110/70 mmHg, pulse is 110/min, and respirations are 22/min. Examination reveals 3/5 strength to right shoulder abduction and elbow flexion/extension and 4/5 strength to right hip flexion/extension. The remainder of the strength exam on the right and left sides is normal. Neck flexion does not elicit pain, and there are no tongue lacerations. During the exam, the patient’s eyes are seen to roll backward with repeated flexion/extension of his extremities and loss of urine. This stops after 1 minute. Which of the following is the most likely diagnosis?