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KEY POINTS
Of the approximately 1.4 million individuals who are evaluated for traumatic brain injuries in emergency departments in the United States each year, 1.1 million are treated and released, 240,000 are hospitalized, and 50,000 die.
In patients with gunshot wounds to the head, the mortality rate is greater than 50% among those who are alive upon presentation to a hospital.
When calculating a Glasgow Coma Scale score, confounding factors include alcohol and other drugs, hypotension, hypoxia, sepsis, hypothermia, and other systemic factors.
Magnetic resonance imaging (MRI) scans provide higher resolution images of the brain, spinal cord, and other soft tissues than computed tomography scans.
In patients with diffuse axonal injury, T2-weighted MRI scans may show multifocal hyperintense lesions at gray matter/white matter interfaces.
As many as 90% of patients with a concussion do not exhibit loss of consciousness; however, when this does occur, it is usually brief.
The modified Monro-Kellie hypothesis states that an increase in the volume of one component inside the skull (brain, intravascular blood, cerebrospinal fluid) or addition of a new component (hemorrhage, tumor) mandates a compensatory decrease in other components to maintain constant intracranial pressure.
Relative indications for surgical elevation of a depressed skull fracture include depression of greater than 8 to 10 mm or greater than the thickness of the adjacent skull, a focal neurologic deficit due to compression of underlying brain, significant inward intrusion of bone fragments, and persistence of cosmetic deformity after overlying scalp swelling has subsided.
An acute subdural hematoma with a thickness of greater than 1 cm or a midline shift of greater than 5 mm should usually be evacuated regardless of Glasgow Coma Scale score.
When intracranial hypertension cannot be controlled by routine measures, hypothermia, barbiturate coma, and unilateral hemispheric decompressive craniectomy should be considered.
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Traumatic brain injury (TBI) remains frustratingly resistant to treatment. Several decades ago, progress in resuscitation, hemostasis, imaging, noninvasive management, critical care, rehabilitation, and emergency medical services organization brought about a decrease in mortality rates, but the failure to develop interventions targeted specifically to the injured brain has inhibited further improvements in outcome. New and developing insights into our classification and approach to TBI may soon pave the way for meaningful advances. Until then, clinicians who care for these patients must rely upon therapies that still await validation in appropriately constructed clinical trials.
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TBI has been defined in many different ways. A good working definition is that it is a disruption or alteration of brain structure or function caused by external mechanical forces. The disruption may be variable in severity and may be transient or permanent. The causative external forces are diverse and include rapid acceleration or deceleration, direct compression, penetration and physical disruption of brain tissue, blast and other complex mechanisms, and various combinations of these and other etiologies. Mild TBI may be present despite absence of abnormalities on imaging studies. At ...