The thing about Alzheimer's is that it fluctuates wildly in the beginning stages. One second my great grandmother was fine, and the next she would freak out because she thought we were strange people that broke into her house. It can be very frightening.
Because of these wild fluctuations, it can be very difficult to say if it is the medication, or lack of sleep, or whatever. I think if it continues, and the doctor wants to take a urine sample, then find a way to do it. She can't always find the words to tell you what's wrong. Its your job to find a way to understand.
Good luck, and Angie is right...you are a good person for taking on such a difficult task!
