Week 7 - Cerebrovascular Disease, Aneurysm, and CNS Infections

cerebrovascular disease

any pathologic condition where blood flow to a region of brain is temporarily/permanently disrupted

ischemic event

occlusion of a blood vessel by thrombus or embolus

hemorrhagic event

rupture of a cerebral blood vessel

common vascular risk factors

HTN, DM, dyslipidemia

smoking, chronic toxin exposure, obesity

age, history of CVA/TIA

ischemic stroke/TIA etiology (3)

AFIB (cardioembolism), large-vessel atherosclerosis, hypercoagulable state

how does AFIB cause Cardioembolism

stasis » clot formation » embolus blocks vessel in heart

Atherosclerosis + examples (2)

narrowed lumen from substance buildup

carotid artery stenosis + aortic arch plaque

Predominantly hemorrhagic etiologies

uncontrolled HTN, arteriovenous malformation (A-V connection without capillaries), coagulopathy (can’t clot), cerebral amyloid angiopathy in older adults

cerebral amyloid angiopathy

etiology of hemorrhagic stroke

brain disorder with buildup of amyloid protein » bleed

TIA imaging

Absence of acute ischemic infarction on diffusion-weighted MRI

TIA indication

warning sign indicating a 2-7 day window of extremely high risk for ischemic stroke

ischemic stroke - 2 zones

core and penumbra

ischemic core

irreversibly damaged tissue undergoing rapid liquefactive necrosis

ischemic penumbra

hypoperfused but structurally viable tissue around dying core

Excitotoxic Cascade with ischemic stroke

ATP depletion > neuronal depolarization > glutamate release into synaptic cleft > NMDA receptor overstimulated > Ca2+ influx > destructive enzymes activated > ROS generated > apoptosis

Intracerebral hemorrhage

vessel rupture within brain parenchyma

Subarachnoid hemorrhage

vessel rupture within subarachnoid space

Hemorrhagic stroke secondary injuries

hematomas exert mass effect, compresses surrounding tissue, increase ICP