Intracranial hypertension is defined as a sustained increase in ICP above which threshold?

Intracranial hypertension is defined as a sustained increase in ICP above which threshold?

• A. 5 mm Hg
• B. 15 mm Hg
• C. 25 mm Hg
• D. 40 mm Hg

Answer: (B)

Intracranial pressure (ICP) is normally kept within a tight range inside the skull. In adults, the upper limit of normal ICP is about 15 mm Hg. When the pressure remains above this level, it is considered intracranial hypertension. The key idea is not just a brief rise, but a sustained elevation, because persistent high ICP can reduce cerebral perfusion pressure (CPP = mean arterial pressure minus ICP). As ICP climbs, CPP falls, risking cerebral ischemia and potential brain herniation. That’s why 15 mm Hg is used as the threshold: it marks the point where pressure shifts from normal to elevated and begins to carry significant clinical risk.

Intracranial pressure (ICP) is normally kept within a tight range inside the skull. In adults, the upper limit of normal ICP is about 15 mm Hg. When the pressure remains above this level, it is considered intracranial hypertension. The key idea is not just a brief rise, but a sustained elevation, because persistent high ICP can reduce cerebral perfusion pressure (CPP = mean arterial pressure minus ICP). As ICP climbs, CPP falls, risking cerebral ischemia and potential brain herniation. That’s why 15 mm Hg is used as the threshold: it marks the point where pressure shifts from normal to elevated and begins to carry significant clinical risk.