What are early signs of delirium versus early signs of dementia?

• A. Delirium: abrupt onset, fluctuating attention and consciousness, disorganized thinking
• B. Dementia: slow, progressive cognitive decline with relatively preserved attention early on
• C. Delirium presents with memory loss only; dementia with motor tremors
• D. Dementia has abrupt onset; delirium is chronic

Answer: (A)

Delirium shows an acute, fluctuating disruption of brain function, especially in attention and level of consciousness, often with disorganized thinking. This combination—sudden change, attention that waxes and wanes, and confused or incoherent thinking—is the hallmark that sets delirium apart from chronic cognitive conditions. In delirium, the mental status can swing over hours to days, and consciousness can be altered from alert to drowsy or agitated, reflecting an underlying acute medical issue or drug effect.

Dementia, in contrast, progresses slowly and steadily. Early on, the main feature is memory difficulty with a gradual decline in other cognitive domains, while attention is typically preserved more than in delirium. This reflects a chronic, degenerative process rather than an abrupt brain dysfunction.

So the strongest early-sign pattern for delirium is abrupt onset with fluctuating attention and consciousness and disorganized thinking, distinguishing it from the gradual, attention-preserving course seen in early dementia. The other descriptions either misstate delirium features or describe dementia’s pattern rather than delirium’s.