The Processes Involved in Traumatic Axonal Injury
Brain injury can be viewed as several clinical syndromes that result from various combinations of neural or vascular events occurring after mechanical distortion of the head. The primary traumatic events appear to be mediated by four basic mechanisms, the consequences of which are not instantaneous. Thus, brain injury involves processes that are set in motion at the time of head injury, but may require hours or days for completion. These four mechanisms of cellular dysfunction are receptor dysfunction, free radical effects, inflammatory events, and calcium-mediated damage and they have the potential for causing delayed cell dysfunction or delayed cellular death. These events, depending on whether they are primarily to the neural or vascular tissues, may produce additional events or epiphenomena, such as brain swelling, cerebral edema, and increased intracranial pressure (see Fig. 1). These types of events are similar in focal and diffuse brain injuries, but their effects may appear to be different because of a different mixture of neural versus vascular tissue involvement, and because of a different combination of the four principal mechanisms of cell damage. This paper addresses the manner in which axons are damaged after injury by these mechanisms.
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- 5.McLellan DR, Adams JH, Graham DI et al (1986) Structural basis of the vegetative state and prolonged coma after non-missile head injury. In: Papo I, Cohadon F, Massarotti M (eds) Le coma traumatique. Padova: Liviana, Padova, pp 165–185Google Scholar
- 8.Graham DI, Lawrence AI, Adams JH et al (1981) Pathology of mild head injury. In: Hoff JT, Anderson TE, Cole TM (eds) Mild to moderate head injury. Blackwell, Boston, pp 3–75Google Scholar
- 10.Saatman K (1992) Biomechanical observations after tensile loading to the isolated sciatic nerve axon in the rat. PhD thesis, University of Pennsylvania, PhiladelphiaGoogle Scholar
- 11.Thibault LE (1992) Brain injury from the macro to the micro level and back again: what have we learned to date?, International Research Council for the Biomechanics of Impact (IRCOBI). Bryon, France 14:3–25Google Scholar