What delirium and acute confusion mean

NICE describes delirium, sometimes called acute confusional state, as a common clinical syndrome with disturbed consciousness, cognitive function or perception, an acute onset and a fluctuating course. It usually develops over 1 to 2 days and should be dealt with urgently.

In care settings, delirium means a sudden change in how a person thinks, responds, moves, communicates or makes sense of their surroundings. The change may be present when someone arrives from hospital or respite, or it may develop during a stay in long-term care.

NICE advises that people in long-term care who are at risk should be observed at least daily for recent changes or fluctuations that could indicate delirium. Practically, that means staff should notice and report day-to-day changes in attention, alertness, movement, mood or engagement.

Delirium is not one fixed picture

• Hyperactive delirium: the person may be restless, agitated, frightened, suspicious or trying to get up unsafely.
• Hypoactive delirium: the person may be sleepy, quiet, slowed down, less engaged, eating less or responding less.
• Mixed delirium: the person may switch between both patterns.

Hypoactive delirium is often harder to recognise because it can resemble tiredness, depression or simply being "not themselves." That is why staff should watch for withdrawal and slowed responses as well as shouting and agitation.

Delirium is about sudden change with fluctuation. If a person's mind or behaviour shifts quickly, think urgent review, not simple personality.