Which features are essential to screen for delirium in acute care?

• A. Acute onset and fluctuations, inattention, altered level of consciousness
• B. Chronic onset and stable attention
• C. Visual hallucinations only
• D. Normal consciousness

Answer: (C)

Delirium is an acute, fluctuating disturbance of attention and cognition. To screen for it in acute care, you look for two core temporal features: an acute onset with fluctuations, and inattention, because these identify a sudden change from baseline. In delirium, there is also a disturbance in arousal or thinking, so you expect either an altered level of consciousness or disorganized thinking as the accompanying feature. Visual hallucinations can occur, but they are not required or specific enough to define delirium. Chronic onset or stable attention points away from delirium toward a chronic condition like dementia, and normal consciousness would argue against delirium. So the strongest screen for delirium combines acute onset with fluctuations, inattention, and an altered level of consciousness or disorganized thinking.