Review Question - QID 108601

A 38-year-old man presents to the emergency department with nasal congestion, blurry vision, and diplopia. His nasal congestion started about 1 week ago and he noticed the blurry vision this morning when he struggled to read the words on his television screen. His medical history is significant for IV drug use, HIV (CD4: 47/mm^3), hypertension, hyperlipidemia, diabetes mellitus, and seasonal allergies. His home medications include hydrochlorothiazide, atorvastatin, metformin, cetirizine, darunavir, tenofovir, and emtricitabine. He denies recent IV drug use. His temperature is 100.8°F (38.2°C), blood pressure is 127/85 mmHg, pulse is 78/min, and respirations are 12/min. He has injected conjunctiva and rhinorrhea. His cranial nerves are intact, and his motor and sensory neurologic exam is normal. A MRI of the brain is performed and can be seen in Figure A. Which of the following is the most appropriate next step in management?