Severe head trauma in multiple injured patients: State of the art of interactions between local and systemic mediator responses

Isolated severe head trauma (SHT) or SHT in combination with multiple injur ies are important factors for the prognosis of morbidity and mortality in p atients suffering from the consequences of accidents. The prognosis mainly depends on the presence of primary mechanic brain injury and the developmen t of secondary brain damage. Causes for the development of secondary brain damage are the intracranial space demand after traumatic injury and edema f ormation which may result in iscemia, as well as inflammatory processes. Bo th isolated SHT and polytrauma with or without brain damage may result in a systemic inflammatory response syndrome (SIRS) due to the synthesis of cyt okines and other inflammatory mediators which may cause a single or multipl e organ failure (MOF). Often the organism is able to survive isolated traum atic injuries and functional disturbances, but in combination or cumulation they may be lethal. The hypermetabolism after SHT is often regarded as an interaction between the central nervous system and the whole organism by th e activation of the neuroendocrine axis. In contrast to the consequences of SHT for the whole organism, multiple injuries after polytrauma may affect brain functions, such as the shock dependent disturbance of the brain perfu sion accompanied by brain hypoxia which may lead to an aggravated prognosis . Moreover, coagulation, metabolism and fracture healing are influenced by the onset of SIRS as well. Our knowledge about the bidirectional inflammato ry interaction between brain and whole organism is still limited. In this c ontext, the effects of secondary surgical interventions which may additiona lly stress a traumatized body have to be considered and are the subject for actual clinical discussions and experimental studies. This article tries t o summarize some important aspects on this topic.