My mom has had dementia for a few years, she doesn't remember the past five years of her life. Just this weekend she has begun hallucinating and what distant memories she had are all now mixing together. She keeps hearing a man's voice who won't shut up (no one else can hear it).
I know a UTI can throw the elderly into a tizzy so I will be getting that checked on Monday. My question is can dementia suddenly get much worse? She also hasn't slept for the past 24 hours because her brain won't shut up long enough for her to rest. Any helpful suggestions would be most appreciated.
Sleeplessness can cause mania behaviour.
Yes, seek medical help to rule some things out.
Once infection and/or UTI is ruled out, yes, dementia can indeed worsen suddenly. The person can take a 'step down' from one day to the next and become entirely different with regard to behavior. I've seen it with my mother who has moderately advanced dementia, although she is not hallucinating or hearing voices *yet*. Getting memories all mixed together IS something that she suffers from, however. It's making her more depressed and angrier than usual, so her doctor is coming in on Tuesday to check her out & do a med evaluation (she lives in Memory Care AL).
Here is a good article on the subject, along with coping techniques:
https://www.alz.org/help-support/caregiving/stages-behaviors/hallucinations
Wishing you the best of luck getting to the root of the problem with your mom. I know how hard all of this is.