Review Question - QID 108764

A 66-year-old man is brought into the emergency department by his daughter for a change in behavior. Yesterday the patient seemed more confused than usual and was asking the same questions repetitively. His symptoms have not improved over the past 24 hours, thus the decision was made to bring him in today. Last year, the patient was almost completely independent but he then suffered multiple TIAs after which his ability to care for himself declined. After the previous episode, he was no longer able to cook for himself or pay his bills but otherwise had been fine up until this episode. He denies any hallucinations and his family denies any sleep walking/talking/acting out. The patient has a past medical history of myocardial infarction, hypertension, depression, type 2 diabetes mellitus, constipation, diverticulitis, and peripheral neuropathy. His current medications include metformin, insulin, lisinopril, hydrochlorothiazide, sodium docusate, atorvastatin, metoprolol, fluoxetine, and gabapentin. His temperature is 98.6°F (37°C), blood pressure is 170/100 mmHg, pulse is 90/min, and respirations are 13/min. On exam, you note a confused man who is unkempt. He has bruises over his legs and his gait seems unstable. He is alert to person and place but answers some questions inappropriately. Which of the following is the most likely diagnosis?