You are a young doctor working the night shift at the surgical ICU. A nurse calls you to a confused patient who is third day after hip replacement (male, age 70, 177 cm, 95 kg). He is not oriented to place, time, or situation. He talks to you as if you were his nephew, his answers don't make any sense. Recently he has been complaining about postoperative pain. What could the differential diagnosis be?
(Also consider monitor, examination and lab tests.)
