What is the definition or description of: raised intracranial pressure?

Increased pressure: The skull is a rigid box of limited volume and increased or raised intracranial pressure is caused by the volume of the brain, blood and spinal fluid exceeding the volume of the skull. This can be due to bleeding, tumors, swelling of the brain or too much spinal fluid. Normal adult icp or intracranial pressure is 10 to 20 mm of hg

Above normal: All persons have pressure in their brain fluid that can vary with position, respiration, bearing down, cough, etc. However, if the fluid pressure is very high, it can cause pressure on structures in and around the brain. The most sensitive test is the spinal tap with pressure monitor that can measure in mm of mercury or cm of water. For high pressures the cause determines the treatment.