MRI Scan showing damage due to brain herniation after TBI
Main article:- Primary and secondary brain injury a large percentage of the people
Killed by brain trauma do not die right away but rather days to weeks after the event,
rather then improving.
Traumatic_brain_injury being hospitalized, some40%of TBI patients deteriorate.
Primary brain injury the damage that occurs at the moment of trauma when tissues and
Blood vessels are stretched, compressed, and >
> and torn is not adequate to explain this deterioration, rather, it is caused by secondary injury,
A complex set of cellular processes and biochemical cascades that occur in the minutes to days
Following the trauma.
These secondary processes can dramatically worsen the damage caused by primary injury and
Account for the greatest number of TBI deaths occurring in hospitals.
Secondary injury events include damage to the blood brain barrier. Release of factors that
Cause inflammation, free radical overlord,
Excessive release of the neurotransmitter glutamate, influx of calcium and sodium ions into
Neurons, and dysfunction of mitochondria .
Injured axons in the brain,s white matter may separate from their cell bodies as a result of
Secondary injury, potentially killing those neurons.Other factors in secondary injury are
Changes in the blood flow to the brain; ischemia cerebral hypoxia insufficient oxygen in the
Brain .Cerebral edema and raised intracranial pressure the pressure within the skull.
Intracranial pressure may rise due to swelling or a mass effect from a lesion, such as a Homorrhage.
As a result, cerebral perfusion pressure the pressure of blood flow in the brain is reduced.
Ischemia results. when the pressure within the skull rises too high, it can cause brain death or
Herniation, in which parts of the brain are squeezed by structures in the skull.
A particularly weak part of the skull that is vulnerable to damage causing extradural haematoma is the pterion, Deep in which lies the middle meningeal artery which is easily damaged in fractures
Of the pterion. Since the pterion is so weak this type of injury can easily occur and can be
Secondary due to trauma to other parts of the skull where the impact forces spreads to the pterion.
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