Traumatic Brain Injury

Related pages

• ICP

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• Traumatic Brain Injury Biomarkers

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• Traumatic Axonal Injury

Pathophysiology

Anatomy

• The brain is a viscoelastic organ with different densities and complex geometry that impact how energy is transmitted through tissues to cause injury.
• Areas most susceptible to injury include the frontal and temporal poles, corpus callosum, and brain stem.
• Natural frequency of each tissue type also likely plays a role in which structures are damaged as does the nature of the force applied (blunt force, blast, whiplash, etc.)
• Frontal lobe injury can lead to difficulties with executive functions (sustained and divided attention, planning, problem solving etc.)
• Temporal lobe dysfunction can include difficulty with language and memory
• Both areas are also involved in emotional regulation
• Injury to subcortical white matter impairs intra and interhemispheric signaling and communication

Edema/ICP Elevation

_{The vicious cycle of head injury}

After severe TBI w/ ↑ ICP → ⊕ feedback loop can ensue, leading ultimately to brain death.

• This situation can be likened to a compartment syndrome w/i the noncompliant skull.
• ↑ of ICP (A) → impedes CBF → ischemia → cytotoxic edema caused in part by ATP–dependent Na+-K+ pump failure.
• This in turn further ↑ ICP & ↓ CBF.
• This situation can ultimately progress to brain death if ICP becomes so high that the cerebrum is not perfused.
  

Articles

Key articles

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IMPACT Study

✓ the value of different prognostic factors in TBI ⇒ the most powerful independent prognostic variables identified were age, GCS motor score, pupil response, and CT finding (Marshall classification), labs (PT & glu) (J Neurotrauma. 2007)

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CRASH trial	✓ effect of early steroids Rx in adults /w TBI ⇒ ↑ death compared to placebo. (Lancet 2004)
CRASH-2	✓ the effects of early TXA Rx in TBI pts /w significant haemorrhage ⇒ ↓ mortality & death d/t bleeding w/o ↑ vascular occlusive events (Lancet 2010)

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DECRA	Efficacy of DC in severe TBI /w refractory ↑ ICP ⇒ DC ↓ ICP & ↓ ICU stay; assoc. /w worse fnx o/c at 6 mn. (N Engl J Med 2011)
RESCUEicp	✓ effectiveness of DC in pts /w TBI & refractory ↑ ICP ⇒ DC ↓ mortality; ↑ risk of severe disability & vegetative state compared to medical Tx alone. (N Engl J Med 2016)

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BEST-TRIP	✓ ICP monitoring in pts /w severe TBI improves o/c ⇒ ICP focused Tx was not better to care based on CT and Px → routine ICP monitoring does not provide additional benefits for pts o/c (N Engl J Med 2012)
Milan Consensus	ICP monitoring in severe adult TBI - not recommended for comatose pts /w nml initial CT that can be f/u Px; recommended for pts w/ bifrontal contusions, s/p 2° DC, WUT is c/i (Acta Neurochir 2014)