Which of the following is a sign of delirium?

• A. Fluctuating acute mental status changes
• B. Steady conscious level
• C. Inattention with disorganized thinking
• D. No perceptual disturbances

Answer: (C)

Delirium is an acute, fluctuating disturbance of attention and cognition often caused by an underlying medical issue, medication effect, or substance withdrawal. The most telling sign is inattention paired with disorganized thinking. Inattention means the person has trouble sustaining or shifting attention, is easily distractible, and difficulty following conversations. Disorganized thinking shows up as rambling, illogical, or incoherent speech and trouble sequencing thoughts. Together, these features reflect the core way delirium disrupts mental processing, often with rapid changes in level of alertness at times.

Fluctuating mental status changes are common in delirium, but the combination of inattention and disorganized thinking specifically demonstrates the characteristic cognitive disruption. A steady conscious level is not typical of delirium, and while perceptual disturbances can occur, their absence does not rule out delirium.