Strokes, Hemorrhage causes and types Flashcards

1
Q

What is cerebral perfusion driven by?

A

PCO2. PO2 only in severe hypoxia.

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2
Q

At what threshold of PO2 will cerebral blood flow increase?

A

Hypoxemia increases cerebral perfusion pressure when PO2 <50.

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3
Q

What is the relationship between cerebral perfusion pressure and PCO2?

A

Linear between 0 and 90 – as PCO2 increases, cerebral blood flow increases.

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4
Q

What does therapeutic hyperventilation accomplish?

A

Blow off CO2, decrease PCO2, decrease cerebral blood flow; helps decrease intracranial pressure via vasoconstriction.

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5
Q

In what scenarios may therapeutic hyperventilation be useful?

A

Acute cerebral edema - stroke, trauma.

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6
Q

What is the formula for cerebral perfusion pressure?

A

CPP = MAP - ICP.

If MAP drops, or ICP too high, CPP drops. If CPP = 0, death.

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7
Q

Where is the most common site of saccular aneurysm?

A

Bifurcations in the circle of willis - most common site is junction of anterior communicating artery and anterior cerebral artery.

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8
Q

What can saccular aneurysm compress?

A

Optic chiasm -> bitemporal hemianopsia.

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9
Q

What does rupture of berry aneurysm cause?

A

Worst headache of my life!!

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10
Q

What diseases are berry aneurysms associated with?

A

APKD, Ehler-Danlos.

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11
Q

What is a charcot-bouchard microaneurysm?

A

Affects small vessels eg basal ganglia, thalamus. Associated with chronic HTN.

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12
Q

What causes pain in central-post stroke pain syndrome?

A

Neuropathic pain to due thalamic lesions. Initial paresthesias followed in weeks/months by allodynia. 10% of stroke patients.

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13
Q

What does the spinal tap for SAH look like?

A

xanthochromic - bloody or yellow.

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14
Q

What complication can occur 2-3 days after subarachnoid hemorrhage?

A

Risk of vasospasm due to blood breakdown. Treat w/ nimodipine. Risk of rebleed too.

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15
Q

How long does it take for irreversible damage to occur w/ hypoxia?

A

5 mins.

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16
Q

What are the most vulnerable areas of the brain to hypoxia?

A

HIPPOCAMPUS, neocortex, cerebellum, watershed areas.

17
Q

How long until CT can detect changes?

A

6-24hr.

18
Q

How long until diffusion weighted MRI can detect changes?

A

3-30mins.

19
Q

What are the histologic features 12-48 hrs after stroke?

A

Red neurons.

20
Q

What are the histologic features 24-72 hrs after stroke?

A

Necrosis and neutrophils.

21
Q

What are the histologic features 3-5 days after stroke?

A

Macrophages - microglia.

22
Q

What are the histologic features 1-2 weeks after stroke?

A

Reactive gliosis + vascular proliferation.

23
Q

What are the histologic features >2 weeks after stroke?

A

Glial scar.

24
Q

What is the threshold for tPA?

A

3-4.5 hrs of onset, no hemorrage/risk of hemorrhage.