Review Question - QID 210066

A 72-year-old man presents to the emergency department with a change in his behavior. The patient is brought in by his family who state that he is not acting normally and that his responses to their questions do not make sense. The patient has a past medical history of diabetes and Alzheimer dementia. His temperature is 103°F (39.4°C), blood pressure is 157/98 mmHg, pulse is 120/min, respirations are 19/min, and oxygen saturation is 98% on room air. A physical exam reveals a systolic murmur heard along the right upper sternal border. HEENT exam reveals a normal range of motion of the neck in all 4 directions and no lymphadenopathy. A mental status exam reveals a confused patient who is unable to answer questions. Laboratory values are ordered and a lumbar puncture is performed which demonstrates elevated white blood cells with a lymphocytic predominance, normal glucose, and elevated protein. The patient is started on IV fluids and ibuprofen. Which of the following is the most appropriate next step in management?