delirium
Meaning of delirium: Delirium is a sudden, fluctuating disturbance of attention and awareness that develops over hours to days, distinct from the gradual decline of dementia.
Definition of delirium
Delirium is an acute disturbance of attention, awareness, and cognition that develops over a short period, typically hours to days, and tends to fluctuate in severity throughout the day. A person experiencing delirium may seem confused, disoriented, or unable to focus, drifting between periods of near normal function and marked impairment.
The condition often includes disorganized thinking, memory difficulty, and altered perception, and some people become agitated or experience hallucinations, while others appear unusually quiet and withdrawn. Sleep and wake patterns are frequently disrupted as well.
Delirium is distinguished from dementia by its rapid onset and fluctuating course, since dementia develops gradually over months or years and does not typically wax and wane over a single day. Delirium commonly arises from an underlying medical problem, such as infection, medication effects, or metabolic imbalance, rather than a primary psychiatric or neurological disease on its own.
Used in a sentence
The nursing staff noted new onset delirium overnight, prompting evaluation for an underlying medical cause.
Good to know
Delirium is frequently mistaken for a primary psychiatric problem or for dementia, though its acute onset and fluctuating course over hours to days distinguish it from the gradual, sustained decline seen in dementia.