Traumatic brain injury (TBI) is the leading cause of death and disability in the young,
active population and expected to be the third leading cause of death in the whole
world until 2020. The disease is frequently referred to as the silent epidemic, and
many authors highlight the "unmet medical need" associated with TBI.The term traumatically
evoked brain injury covers a heterogeneous group ranging from mild/minor/minimal to
severe/non-salvageable damages. Severe TBI has long been recognized to be a major
socioeconomical health-care issue as saving young lives and sometimes entirely restituting
health with a timely intervention can indeed be extremely cost efficient.Recently
it has been recognized that mild or minor TBI should be considered similarly important
because of the magnitude of the patient population affected. Other reasons behind
this recognition are the association of mild head injury with transient cognitive
disturbances as well as long-term sequelae primarily linked to repeat (sport-related)
injuries.The incidence of TBI in developed countries can be as high as 2-300/100,000
inhabitants; however, if we consider the injury pyramid, it turns out that severe
and moderate TBI represents only 25-30 % of all cases, while the overwhelming majority
of TBI cases consists of mild head injury. On top of that, or at the base of the pyramid,
are the cases that never show up at the ER - the unreported injuries.Special attention
is turned to mild TBI as in recent military conflicts it is recognized as "signature
injury."This chapter aims to summarize the most important features of mild and repetitive
traumatic brain injury providing definitions, stratifications, and triage options
while also focusing on contemporary knowledge gathered by imaging and biomarker research.Mild
traumatic brain injury is an enigmatic lesion; the classification, significance, and
its consequences are all far less defined and explored than in more severe forms of
brain injury.Understanding the pathobiology and pathomechanisms may aid a more targeted
approach in triage as well as selection of cases with possible late complications
while also identifying the target patient population where preventive measures and
therapeutic tools should be applied in an attempt to avoid secondary brain injury
and late complications.
