Are confusion, agitation, hallucinations, aggression, and yelling indicative of bipolar disorder?

Hello doctor,

My 76-year-old high-functional mom was just diagnosed with bipolar. She has confusion, agitation, hallucinations, aggression, yelling, and some hours of clarity mixed with the above. For the past ten years, I have seen this behavior with her whenever she has an infection (usually UTI). This is the first sign that we know she is having an infection. She then usually gets diagnosed with an infection and gets treated with an antibiotic and her behavior completely clears. She was recently diagnosed with ESBL in her urine and has had three unsuccessfully treated UTIs. She ended up in the hospital for her altered mental status. She was dehydrated but they could not find any sign of infection. They put her in the adult behavioral unit at the hospital pumped her full of antipsychotic medications and said she is bipolar. No neurological testing was performed. I insist there is an infection and the hospital insists it is a psychiatric behavioral problem. How is it possible that for ten years this behavior always signified an infection and now it signifies bipolar? Kindly help.