What you need to know about: delirium in older adults in hospital.

Delirium is a clinical syndrome characterised by a disturbance of perception, consciousness and/or cognitive function, with an acute onset, fluctuating course and a severe deterioration arising over hours or days. Delirium is usually triggered by a combination of influences including acute illness, surgery, drugs and environmental factors. It is commonly seen in older people presenting to hospital, but can also develop during hospitalisation. There are three types of delirium: hypoactive, hyperactive and mixed. All patients over 65 years old presenting to hospital should be screened for delirium using the '4AT' tool. An alternate method for diagnosing hospital-acquired delirium is described. This article outlines a 10-stage method for diagnosing, managing and preventing delirium, with emphasis on which areas of the history and examination should be prioritised, what the salient investigations are and both non-pharmacological and pharmacological approaches to preventing and treating delirium. Finally, this article explores which patients require specialist referrals or investigations and how to best follow up patients with delirium.