UTIs are among most common infections in the elderly. Agitation, delirium, behavioral changes may be the only sign of a UTI.
From WebMD. Just wanted to send this out as I have experienced this with my aunt and mom both. Delerium and sundowner was so severe that strong halucination drugs were prescribed for my aunt. Thanks to this website, I asked for UTI test. Mom's reactions were longer lasting as it manifested only as advancing of her alzheimer's. Due to the disease, she fights changing underware and fails to clean herself well. It's a constant challenge.