Flashcards in Strokes, Hemorrhage causes and types Deck (24):
What is cerebral perfusion driven by?
PCO2. PO2 only in severe hypoxia.
At what threshold of PO2 will cerebral blood flow increase?
Hypoxemia increases cerebral perfusion pressure when PO2 <50.
What is the relationship between cerebral perfusion pressure and PCO2?
Linear between 0 and 90 -- as PCO2 increases, cerebral blood flow increases.
What does therapeutic hyperventilation accomplish?
Blow off CO2, decrease PCO2, decrease cerebral blood flow; helps decrease intracranial pressure via vasoconstriction.
In what scenarios may therapeutic hyperventilation be useful?
Acute cerebral edema - stroke, trauma.
What is the formula for cerebral perfusion pressure?
CPP = MAP - ICP.
If MAP drops, or ICP too high, CPP drops. If CPP = 0, death.
Where is the most common site of saccular aneurysm?
Bifurcations in the circle of willis - most common site is junction of anterior communicating artery and anterior cerebral artery.
What can saccular aneurysm compress?
Optic chiasm -> bitemporal hemianopsia.
What does rupture of berry aneurysm cause?
Worst headache of my life!!
What diseases are berry aneurysms associated with?
What is a charcot-bouchard microaneurysm?
Affects small vessels eg basal ganglia, thalamus. Associated with chronic HTN.
What causes pain in central-post stroke pain syndrome?
Neuropathic pain to due thalamic lesions. Initial paresthesias followed in weeks/months by allodynia. 10% of stroke patients.
What does the spinal tap for SAH look like?
xanthochromic - bloody or yellow.
What complication can occur 2-3 days after subarachnoid hemorrhage?
Risk of vasospasm due to blood breakdown. Treat w/ nimodipine. Risk of rebleed too.
How long does it take for irreversible damage to occur w/ hypoxia?
What are the most vulnerable areas of the brain to hypoxia?
HIPPOCAMPUS, neocortex, cerebellum, watershed areas.
How long until CT can detect changes?
How long until diffusion weighted MRI can detect changes?
What are the histologic features 12-48 hrs after stroke?
What are the histologic features 24-72 hrs after stroke?
Necrosis and neutrophils.
What are the histologic features 3-5 days after stroke?
Macrophages - microglia.
What are the histologic features 1-2 weeks after stroke?
Reactive gliosis + vascular proliferation.
What are the histologic features >2 weeks after stroke?