An 80 year old woman has open reduction and internal fixation of an intertrochanteric fracture. On the second post-op day she begins having visual hallucinations. Her medical history includes hypertension, CHF, osteoarthritis, hypothyroidism, constipation, and anxiety. She has no history of dementia. Medications at admission were furosemide, digoxin, L-thyroxine and sorbitol.
Physical examination is normal except for agitation and inability to pay attention to questions.
A 93 year old man with mild dementia is admitted to the hospital with pneumonia and is treated with ampicillin. The next day he develops a diffuse maculopapular rash, which is thought to be a drug reaction. The ampicillin is stopped and trimethoprim-sulfamethoxazole is begun. During the night he becomes confused and anxious. The next day he remains agitated and calling out.