Medscape indicates that normal intracranial pressure is between 7 and 15 millimeters of mercury in supine adults laying on their back. Abnormal ICP begins at more than 15 mm Hg, and pathological problems in the brain start with an ICP of 20 mm Hg or greater. When the head is elevated, ICP generally decreases.
A standing adult has a normal ICP of -10 mm Hg, but not less than -15 mm Hg, according to Medscape. Children generally have lower supine ICP readings, and infants have negative ICP readings regardless of their position.
ICP increases with head trauma, brain lesions, intracranial tumors, cerebral edema and metabolic disorders such as hepatic encephalopathy. ICP measures the brain volume within the skull, as ICP increases when brain volume rises due to inflammation, according to Medscape.
Treatment for increased ICP includes elevating the head, decreasing neurological stimulation, an intravenous solution of Mannitol, steroids, surgical decompression and a medically induced coma, according to the University of Michigan. These treatments depend on the severity and type of symptoms associated with an increased ICP.
Medscape explains that ICP values are measured in mm Hg for quick conversions to cerebral perfusion pressure and for easy comparison to mean arterial blood pressure. The University of Michigan School of Medicine states CPP is the MAP minus ICP.