My mom is 64. I went over to visit her, and out of nowhere, she pulled down BOTH pairs of pants she was wearing, sat on the couch and loudly declared "I'm peeing here." After checking her pulse, BP, and oxygen stats, I was convinced to take her into the ER. There I learned she had an out-of-control bladder infection, and had I waited longer, she might have succumbed in a few days. She's been on antibiotics for two days, and she now recognizes me again. The nurses informed me that when an older patient has a bladder infection or UTI it frequently presents with confusion.
So! If your older parent/grandparent suddenly thinks the dog is talking to shoes and that the president is JFK, take them into the hospital and try to make them drink cranberry juice. You could save their life.
