Hyperosmosis of cerebral injury

Changes in tissue osmolarity or cerebrospinal fluid osmolarity after cerebr al injury have received little attention in the literature, but osmosis may be an important cause of early cerebral edema; This paper reviews concepts and terms relating to osmosis, and reviews the few papers in the literatur e which have studied osmolarity after cerebral injury. In studies of both t raumatic brain injury and ischemia, tissue osmolarity is elevated. Osmolari ty of cerebrospinal fluid has also been shown to increase with injury. Ther e have been no human studies examining osmolarity of tissue or cerebrospina l fluid after cerebral injury. Theoretical implications of the osmotic grad ient are discussed.