Delirium is defined as which of the following?

• A. Chronic progressive cognitive decline
• B. acute altered state of consciousness with agitation and disorientation
• C. Transient loss of consciousness due to fainting
• D. Delusion without confusion

Answer: (B)

Delirium is an abrupt, fluctuating disturbance of consciousness and attention with accompanying cognitive impairment. It typically evolves over hours to days and is characterized by inattention, disorganized thinking, and a change in the level of arousal, which often presents as agitation or restlessness (though it can also be hypoactive). This contrasts with dementia, which is a chronic, progressively worsening decline in cognition over months to years, not an acute fluctuation. It also differs from syncope, a transient loss of consciousness due to brief cerebral hypoperfusion, and from psychosis with delusions but without the marked attention and awareness disruption that delirium features. The description that best fits delirium emphasizes an acute, altered state of consciousness with disorientation and cognitive disturbance.