normal rate of CBF
CBF decreases to this rate and neurons stop firing but are still viable: ischemic penumbra
CBF decreases to this rate and brain cells are irreversibly dead r/t lactic acidosis and cytotoxic edema
causes of ischemic stroke
large artery artherosclerosis, cardioembolic events, small artery occlusive disease
large artery artherosclerosis
caused by cholesterol plaque, thrombus on plaque or embolis
risk factors for large artery artherosclerosis (and also for stroke)
HTN, Diabetes, smoking and possibly high cholesterol
caused by A fib, rheumatic heart disease, AMI, endocarditis, mitral valve stenosis and prosthetic heart valves
mechanism of action of cardioembolic stroke
clot formation due to low flow of blood from the heart
cardiac abnormality is the source of the emboli causing stroke in the first place
why important to treat underlying cardiac problem as well as neuro problem when someone has cardioembolic stroke?
HTN, Diabetes, small vessel occlusive disease cause this type of stroke where fat coats cerebral arteries in brain and thickens walls causing stroke
places in brain lacunar stroke most often occurs
basil ganglia, sub cortical white matter, thalamus, cerebellum and brainstem
10 -12 x's more often
Lucunar strokes occur how much more often than other types of stroke?
one of the cognitive deficits caused by lucunar stroke
pure motor, pure sensory or both
patients can present with which features when they have a lucunar stroke?
primary causes of hemorrhagic stroke
primary intraparenchymal hemorrhage, ruptured cerebral aneurysm, AV malformation
secondary causes of hemorrhagic stroke
over anticoagulation (heparin, warfarin or rtPa), vasopressors, cocaine abuse, liver or renal failure, thrombcytopenia
bleeding into brain substance from uncontrolled HTN
cause of intraparenchymal hemorrage
percentage of hemorrhagic strokes caused by intraparenchymal hemorrhage
location of bleeding, compression and herniation
what does the severity of stroke from intraparenchymal hemorrhage depend on?
risk of rupture and hemorrhage into sub arachnoid space
what does AV malformation increase the risk of?
AV malformation impairs what?
complications of AV malformation
ischemia, scarring of brain tissue, abnormal tissue development, compression, hemorrhage and hydrocephalus