Mother with moderate Alzheimer’s. Suddenly became delirious and aggressive one morning, taken to hospital. What's going on?

The antibiotics should help. My dad is in the hospital after becoming EXTREMELY confused and violent over the weekend. Very much out of character from his 'normal' dementia. He had been doing so much better but the SNF and myself noticed a huge difference over a few days time. He was sent to the hospital. Tested negative for UTI. Dad continually deals with cellulitus infections in his legs and the hospital said the one he currently has is not doing very well and they felt his agitation was caused from the infection that was not responding to oral antibiotic treatment. They put him on IV antibiotics and yesterday when he called, he sounded like his old self. He said he was anxious to get back to the SNF but does not remember how or why he was put in the hospital.

Although a UTIs are a common cause of a rapid change in behaviour, another infection could have a similar result. Have they done a complete blood panel?

Has she had a recent change in medication, as in within the last month?

I want to second the idea of re-doing the urine culture.

Has a psych consult been requested? Many years ago, my father in law had altered mental status. It was the psychiatrist who figured out that he had had a stroke.

For now your mother is a mystery. My first vote would have gone to checking for a UTI and I would still caution be certain that a culture was done. Not all UTI will show on regular urine exam amazingly enough, and I found this out the hard way. Also do know that not all strokes show up easily. Bleeds do, on scan, but strokes don't always. I think right now you are in the hands of neurologists. Anything we say is guesswork. What you are seeing, to happen so suddenly, is, -yes--rare. I hope you will update us as diagnostics continue.