Which of the following is a sign of cerebral herniation?

• A. Elevated heart rate
• B. Deteriorating level of consciousness
• C. Normal pupil reactivity
• D. Stable respiratory pattern

Answer: (B)

Rising intracranial pressure that pushes brain tissue toward the brainstem impairs consciousness and brainstem function. A deteriorating level of consciousness is the clearest and most immediate signal that this dangerous process is occurring, because the reticular activating system and cortex lose their ability to maintain alertness as compression progresses. In practice, a patient who slips from being awake and oriented to sleepy, confused, or unresponsive is showing a warning sign that herniation may be developing, which demands urgent intervention and rapid evacuation.

Other signs can occur but are less reliable or occur later. Heart rate often does not rise as a hallmark; the classic response to intracranial pressure is a Cushing triad with high blood pressure and a slower pulse, not a simple elevated heart rate. Pupil changes can accompany herniation (such as unequal or nonreactive pupils) but normal pupil reactivity argues against significant herniation. Respiratory patterns typically become irregular or labored as brainstem compression worsens, not remain stable.