What are the key clinical features to differentiate delirium from other causes of acute confusion in older adults?

The key clinical features used to differentiate delirium from other causes of acute confusion in older adults primarily involve the **recent onset** (within hours or days) and **fluctuating nature** of symptoms ³. These changes may be reported by the person at risk, or a carer or relative ³.

• Cognitive function: Indicators include worsened concentration, slow responses, and confusion ³.
• Perception: Changes may involve visual or auditory hallucinations ³.
• Physical function: Features can include reduced mobility, reduced movement, restlessness, agitation, changes in appetite, and sleep disturbance ³.
• Social behaviour: This may manifest as difficulty engaging with or following requests, withdrawal, or alterations in communication, mood, and/or attitude ³.

It is particularly important to be vigilant for changes that may indicate **hypoactive delirium**, which are often missed, such as withdrawal, slow responses, reduced mobility and movement, worsened concentration, and reduced appetite ³. While it can be difficult to distinguish between delirium, delirium superimposed on dementia, or dementia alone, clinical guidelines advise managing delirium first due to its nature as a reversible and serious acute illness ¹,³.