I saw my cardiologist today. He is the lipids expert at the university and is treating me for Metabolic Syndrome. He doesn't see people as a cardiovascular system, though. He is the only doctor other than a psychiatrist who consistently asked about my caregiving on every visit for 10 years.
I mentioned my mother today. He told me that he was consulted once about a colleague's elderly patient who seemed to have a heart condition. He did diagnose a-fib. He was called by the colleague's office and told "Doctor, I wonder if you checked the wrong box on this form. You seem to be asking for a urine test." He explained to me that the doctors are always polite to each other, but that the underlying message was "We asked your cardiology opinion. What the heck are you doing with a urine test!" He replied that the lady was suddenly focused and disoriented and he suspected a UTI, which should be treated if other treatments were to be effective. He also said it politely but the underlying message was "Why on earth didn't the internist order this test?! The elderly lady did indeed have a UTI. My cardiologist suspects that internist learned something from that consultation!
Moral of the story, to me at least, is if an elderly loved one suddenly has dementia-like symptoms or a person with dementia suddenly has greatly increased symptoms. ask for a test for a UTI -- even if the doctor doesn't suggest it herself or himself! It may not be UTI, of course, but ruling that out is a reasonable first step.