Stroke Pathophysiology

Question 1

ischemic stroke

Answer 1

occurs when arterial blood flow to the brain fails to meet the metablog demands of the cells, resulting in damage or cell death.

Question 2

hyperacute phase of ischemic stroke

Answer 2

penumbra surrounds the core infarct or dead tissue (cells are damaged but not yet infarcted);
penumbral tissue is functionally silent but metabolically active; restoring blood flow quickly can save tissue

Question 3

Hypoxia/Anoxia in ischemic stroke

Answer 3

central mechanism of cell death. Occurs in 1 of 2 ways: necrotic or apoptic pathways

Question 4

Necrotic pathway of cell death

Answer 4

cell energy failure and rapid death. activated by loss of oxygen and glucose

Question 5

Apoptic pathway of cell death

Answer 5

programmed cell death in the penumbral zone. Normal biologic function wherein cells are programmed to die in organized fashion following cell death (to dispose of redundant cells)

Question 6

ICH

Answer 6

occurs when a cerebral blood vessel opens abnormally and spills blood into brain tissue. Abnormal blood into brain tissue results into cascade of damage to surrounding tissue

Question 7

primary brain injury in ICH

Answer 7

–results directly from pressure incurred from hematoma formation.
–deficits seen in minutes to hours after ICH related to primary brain injury.
–mechanical pressure and resulting mass effect from hematoma causes cell damage or tissue death

Question 8

secondary brain injury in ICH

Answer 8

results hours to days after ICH; mechanical disruption to and deformation of cell membranes
– cell damage leads to influx of electrolytes
– damage from cell death, blood-brain barrier disruption, vasogenic edema

Question 9

SAH

Answer 9

occurs when an aneurysm forms and ruptures, resulting in blood spilling in to the subarachnoid space

Question 10

Aneurysm rupture (SAH)

Answer 10

at moment of rupture, mechanical injury from blood rushing in to subarachnoid space. Results in sudden increase in ICP and mass effect

Question 11

Early brain injury (EBI) in SAH

Answer 11

hours to first several days; generalized cerebral edema forms. EBI results from reduction of cerebral blood flow in microcirculation of brain spreading ischemia

Question 12

Cerebral Vasospasm in SAH

Answer 12

large vessel vasospasm generally from 4 to 21 days post rupture.
–exact patho not fully understood