Traumatic brain injury is a major cause of death and disability among a predominantly young population. Recent estimates of incidence are roughly 10 million cases / year worldwide. Secondary brain injury can be defi ned as those processes that occur after the primary brain injury, but contribute to the pathogenesis of TBI. Thus elevated ICP, decreased CBF, hemorrhage, and the neurochemical injury cascade are endogenous elements of secondary brain injury. Secondary injury can also be introduced by exogenous or iatrogenic events: inadeguate resuscitation of circulatory shock, nosocomial infection, anesthetic agents, alcohol and other factors. This review adresses new concepts and information in the pathophysiology of TBI and secondary brain injury and demonstrates haw emergency management may by linked to neurologic autcome.