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27 Cards in this Set
- Front
- Back
What is a concussion?
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a mild TBI
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Contact loading and inertial loading ultimately cause what?
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Diffuse Axonal Injury
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If a patient has contact loading, what must they be upgraded to on the GCS?
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Moderate
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What structure on the brain causes midline injury in inertial loading?
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falx cerbrae
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Histologically, what is seen in diffuse axonal injury?
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See amyload plaques where it should all be white
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In terms of elongation, what causes neuronal injury?
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Neurons can stretch, but in trauma the speed of stretch can cause them to snap
Recall: silly puddy example |
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What is the most important factor in the severity of an injury?
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SPEED of injury
That's why blasts (microseconds) are so deadly |
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Histologically, what is seen in a single neuron damaged due to trauma?
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Swelling of neuron then disconnection
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What is the most important and most common pathology of mTBI / concussion?
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Diffuse Axonal Injury
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Can you usually see DIA / mTBI on imaging?
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NO
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After stretching/elongation, what pattern is seen in neurons?
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Delayed elastic response - see an undulation pattern
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Within the neuron, what does stretching break?
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Microtubules
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What allows for relaxation of undulations?
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Post-injury depolymerization of microtubules
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What is sacrificed as a result of post injury depolymerization of microtubules?
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Lose Microtubules - affects axon transport
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What is responsible for the formation of axonal variscosities?
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Partial transport interruption
(caused by mechanical breakage of individual microtubules staggered between microtubules) |
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What does taxol do?
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Inhibits axon degeneration
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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 |
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In terms of ion channels, trauma immediately damages what?
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Na channel inactivation gate
Causes massive Na+ influx |
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Massive Na influx causes what?
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Reversal of the Na-Ca++ exchanger and activation of VSCC
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The massive Na influx, resulting in reversal of Na/Ca exchanger, ultimately results in what?
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Massive Ca++ influx
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Why is the massive influx of Ca particularly damaging?
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because can activate proteases and get actually protelyse Na channels
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What is the "period of vulnerability" in repetitive mTBI?
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Time period when another mild injury is thought to trigger a greatly exaggerated response
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Trauma increases the density of what in a neuron?
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Na channels - gives Na channelopathy! (NaChO)
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What is the source of immediate loss of consciousness and coma following brain trauma?
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DAI (diffuse axonal injury)
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Approximatly 30% of TBI cases have what on histology?
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Diffuse plaquess composed of amyloid-B
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Apart from plaques, what other pathology is seen in mTBI?
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Neurofibrillary Tangles
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TBI increases the risk of developing what?
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Alzheimer's disease
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