Most causes of dementia are irreversible BUT there are treatable causes
Demented patients with an acute change in mental state should be assessed for causes of delerium
(see also Causes for delerium, Screening for organic illness in disturbed patients)
Neurosurgical lesions - Normal pressure hydrocephalus, chronic subdural haematoma
INVESTIGATIONS - 'Dementia screen'
Most of these can be done on the ward:
CXR (if symptoms of infection or evidence of hypoxia)
CT Brain (if history of head trauma, focal neurology or cause not established)