Which is an early sign of increased intracranial pressure?

• A. Decreasing level of consciousness
• B. Cushing's triad
• C. Unexpected vomiting
• D. Dilated pupil with sluggish response to light

Answer: (A)

Changes in level of consciousness are the earliest clue that intracranial pressure is rising. As ICP starts to climb, cerebral perfusion pressure drops (CPP = MAP − ICP). Reduced perfusion makes brain tissue ischemic and affects the reticular activating system, leading to restlessness, confusion, drowsiness, or a decreased level of alertness—the first signs clinicians look for.

The other signs reflect more advanced brain involvement. Cushing’s triad (hypertension with bradycardia and irregular respirations) indicates brainstem compression and is a late finding. A dilated pupil with a sluggish reaction to light signals cranial nerve III compression from herniation, another late sign. Vomiting can occur with ICP rise but is not as reliable an early indicator as changes in consciousness.

So, the earliest and most sensitive sign is a decreasing level of consciousness, signaling the need for immediate assessment and intervention to prevent progression.