Why do UTIs affect people with dementia the way they do?

Just a guess here as I'm not a medical professional, but I suspect the infection spreads quicker to more debilitated bodies which can't fight back as easily as younger persons. Elderly are just so much more vulnerable in so many ways.

Dr.'s aren't even sure why elderly people with UTI's become confused (or more confused if they already have dementia). But any kind of virus or infection can cause confusion in an elderly person. UTI's are just more common.

I'm not sure, Nikki, but I think the elderly have different symptoms from UTIs than younger people do -- whether they have dementia or not. One of my aunts lived to be 100 with no signs at all of dementia, but when she had a UTI in her 80s she hallucinated and had delusions.

That doesn't really answer your question as to WHY it happens, but it is very useful to know that it does, if you are caring for an older person.