Poor differentiation of the type and cause of confusion in the elderly is associated with poor outcomes (i.e. increased mortality/morbidity, prolonged hospital stays, and functional decline).
Confusion in the elderly can be categorized into three types with the following typical features:
Delirium - caused by organic illness, acute onset, agitated or drowsy, variable short-term memory, disorganized thoughts, hallucinations.
Dementia - chronic confusion due to long-term neurologic illness like Alzheimer's disease, progressive, irreversible, short-term memory loss, simple task performance and language impairment, aggression, personality changes.
Acute or Chronic Confusion - treatable illness (i.e. infection) triggers delirium in patient with baseline dementia.