Delirium

Delirium is a sudden, fluctuating disturbance in attention, awareness, and thinking, often triggered by an underlying acute illness. It is common, particularly in older adults during hospital admission, and represents a medical emergency requiring prompt identification of the underlying cause.

• Sudden onset of confusion, developing over hours to a day or two
• Reduced ability to focus, sustain, or shift attention
• Fluctuating level of alertness — which can range from drowsy to agitated — often worse at night
• Disorganised thinking or rambling, incoherent speech
• Changes can be subtle (quiet, withdrawn) or more obvious (agitated, distressed), and may be missed if not specifically looked for, especially in older adults

• Almost always results from an underlying acute physical illness or its treatment, rather than being a primary mental health condition.
• Common triggers include infection (such as a urinary tract infection or pneumonia), dehydration, medicine effects or interactions, uncontrolled pain, low blood sugar, and alcohol withdrawal.
• Risk is greatly increased by older age, pre-existing dementia, severe illness, and multiple medicines.

• Diagnosed clinically based on the sudden onset and fluctuating course of confusion and inattention, distinguishing it from dementia, which develops gradually over months to years.
• A thorough search for the underlying cause is essential and includes assessment for infection, dehydration, medicine review, and checking blood glucose and other relevant tests.
• It is important to gather history from family or caregivers, since the person themselves may not reliably describe the change, and to compare with their usual baseline mental state.

Identifying and treating the underlying cause is the priority — for example, treating an infection, correcting dehydration, adjusting or stopping a contributing medicine, or managing pain.

Supportive, non-pharmacological measures help — such as ensuring a calm, well-lit, quiet environment, frequent reorientation (reminding the person of the date, place, and what is happening), ensuring glasses and hearing aids are used if needed, and involving familiar family members where possible.

Medicine to calm agitation is used cautiously and only when necessary for safety, as it does not treat the underlying cause and can sometimes worsen confusion, particularly in older adults.

Delirium usually resolves once the underlying cause is treated, though recovery can take days to weeks, and older adults or those with underlying dementia may take longer to return to their baseline.

• Ensure prompt treatment of infections and other acute illnesses, particularly in older adults.
• Maintain good hydration, especially during illness or hospital admission.
• Review medicines regularly in older adults to minimise those that can contribute to confusion.
• Support orientation for hospitalised older adults — familiar objects, clear communication, and family visits — as this can help reduce the risk and severity of delirium.
• Seek prompt medical assessment for any sudden change in a person's alertness or thinking, as this always warrants investigation rather than being dismissed as "just confusion".