sadly, anyone can get dementia
sometimes it can appear sudden if symptoms have gone unnoticed
sometimes it is due to a TIA or stroke and can seem to appear suddenly
sometimes delerium due to some other cause can lead to dementia
and UTIs or any infections can highlight and heighten symptoms
Delirium can appear very suddenly, seemingly out of nowhere, and it can look a lot like dementia (confusion, hallucinations, inability to perform everyday tasks etc). Once the cause of he Delirium has been treated (usually an infection) the symptoms of Delirium should go away but sometimes this doesn’t happen. Delirium sometimes ‘unmasks’ dementia. I’m not quite sure why but perhaps because there was already some brain damage and the Delirium has caused some more.
My fit and active Mum was like that. She had managed to "hide" it for a long time and it was only when she suddenly started accusing people of stealing from her that I suddenly realised something was wrong. Later when I took over her finances and cleared her home it became obvious that things had not actually been right for some time, but to meet her you would have had no idea