Correct answer b and d
It is likely that Dr Zheng’s Alzheimer’s disease is progressing. Stroke seems unlikely (a) as there is no new focal neurologic impairment. However it is important to exclude causes of delirium and other physical health problems. (b) It is much more likely that Dr Zheng’s symptoms result from dementia, rather than a new mental health disorder such as bipolar disease (c) Reviewing use of 'over the counter' and prescribed medicines is important (d) Many patients and their families want to limit investigations (e) but basic investigations seem justified at this point .