Confusion and delirium in the acute setting

Confusion and delirium are the most common behavioural disorders seen in emergency departments and acute medical or surgical units. Delirium can be regarded as the new ‘cognitive superbug’. Confusion can be seen as a mild form of delirium and can give warning of the development of the more severe disorder. It causes an acute change of mental status characterized by abnormal and fluctuating attention. It affects 10–30% of medically ill patients, especially elderly individuals and often shortly after hospital admission. It causes prolonged admission, increased morbidity and mortality, and delayed discharge, often culminating in long-term care. Its causation is reviewed and its prevention and management are described.