MSFinals-3100

MSFinals-3100

A 67-year-old gentleman is admitted following a fall with a painful right knee. He has a history of osteoarthritis and atrial fibrillation (AF). Prior to admission, he was independent and living alone. While in the Emergency Department, he gives a history of falling on his knee. Staff reported an incident of urinary incontinence while in their care. No seizure activity was reported. While on the ward, he becomes sleepy but arousable. Later in the night, the nurses state he is no longer opening his eyes to voices and is making incomprehensible noises.
What is the most important potential diagnosis which requires exclusion?