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27 Cards in this Set

  • Front
  • Back
What is a concussion?
a mild TBI
Contact loading and inertial loading ultimately cause what?
Diffuse Axonal Injury
If a patient has contact loading, what must they be upgraded to on the GCS?
Moderate
What structure on the brain causes midline injury in inertial loading?
falx cerbrae
Histologically, what is seen in diffuse axonal injury?
See amyload plaques where it should all be white
In terms of elongation, what causes neuronal injury?
Neurons can stretch, but in trauma the speed of stretch can cause them to snap

Recall: silly puddy example
What is the most important factor in the severity of an injury?
SPEED of injury

That's why blasts (microseconds) are so deadly
Histologically, what is seen in a single neuron damaged due to trauma?
Swelling of neuron then disconnection
What is the most important and most common pathology of mTBI / concussion?
Diffuse Axonal Injury
Can you usually see DIA / mTBI on imaging?
NO
After stretching/elongation, what pattern is seen in neurons?
Delayed elastic response - see an undulation pattern
Within the neuron, what does stretching break?
Microtubules
What allows for relaxation of undulations?
Post-injury depolymerization of microtubules
What is sacrificed as a result of post injury depolymerization of microtubules?
Lose Microtubules - affects axon transport
What is responsible for the formation of axonal variscosities?
Partial transport interruption

(caused by mechanical breakage of individual microtubules staggered between microtubules)
What does taxol do?
Inhibits axon degeneration
What is the overall pathogenesis of TAI?

(6 steps)
1. Primary breakage of microtubules

2. Broken microtubules impede relaxation = undulation

3. Secondary MT chemical "castrorophe" begins at break sites

4. Relaxation of undulations, but disruption of transport

5. Swelling and disconnections

6. Axonal Degeneration
In terms of ion channels, trauma immediately damages what?
Na channel inactivation gate

Causes massive Na+ influx
Massive Na influx causes what?
Reversal of the Na-Ca++ exchanger and activation of VSCC
The massive Na influx, resulting in reversal of Na/Ca exchanger, ultimately results in what?
Massive Ca++ influx
Why is the massive influx of Ca particularly damaging?
because can activate proteases and get actually protelyse Na channels
What is the "period of vulnerability" in repetitive mTBI?
Time period when another mild injury is thought to trigger a greatly exaggerated response
Trauma increases the density of what in a neuron?
Na channels - gives Na channelopathy! (NaChO)
What is the source of immediate loss of consciousness and coma following brain trauma?
DAI (diffuse axonal injury)
Approximatly 30% of TBI cases have what on histology?
Diffuse plaquess composed of amyloid-B
Apart from plaques, what other pathology is seen in mTBI?
Neurofibrillary Tangles
TBI increases the risk of developing what?
Alzheimer's disease