<s>[INST] Hi there my mother aged 90 lives has lived in a resthome for 2 years following a stroke and various TIA s. Recently she has become on some days mentally completely confused (not even knowing where she is or who we are). Other days she is her usual old self. She has had many urinary tract infections which I understand can cause mental problems? but understand she hasn t got one at the moment. She also has a bad skin cancer on her cheek which is to be removed soon. Could this be a cause? If not can you enlighten us as to why she can be so mentally alert one day and confused to buggery the next. Thanks in anticipation. [/INST] Hi and .Thanks for the query.It is hard to say but it is to be expected in older people. However,if there is sudden and significant change in her mental status it may indicate some neurologic disease so ct brain scan is the first thing to think of. it may reveal ischemic changes,tumors or atrophy. also, any other metabolic or heart disease may lead to confusion as well.  Wish you good health. Regards </s>