SDL: Vasculopathology Flashcards
some conditions associated with hypotension
myocardial infarct, ruptured aortic aneurysm, severe GI bleeding, bleeding from trauma, septic shock
most sensitive areas to ischemic (red) neurons
Sommer’s sector of hippocampus, purkinje cells
where does laminar necrosis occur?
watershed infarcts at border-zone areas
characteristics of brain death
absence of perfusion, reflexes, respiration
isoelectric (flat) EEG
respirator brain- in vivo autolysis of brain when patient is kept alive by mechanical ventilation (good organ donors)
causes of a focal hypoxia/ischemia episode
emboli occlusion, mural thrombus or vegetations from heart following an MI, neoplastic emboli
most emboli go to this artery
middle cerebral artery
causes of hemorrhagic infarction
occlusion of artery is incomplete, so there is recirculation of blood
embolus- breaks up, moves distally
extrinsic compression of artery
vasospasm
reperfusion of infarct
treatment of hemorrhagic infarct
IR goes to the occluded artery using a catheter, administers tPA to lyse the thrombus
most common cause of cerebrovascular accidents
atherosclerosis
what happens to the infarcted tissue the first 12-24 hours? when is it considered an infarction?
red neurons, eosinophilic neuronal necrosis, acute neuronal injury
24 hours
when do neutrophils infiltrate infarcted tissue?
2-7 days
what happens when macrophages remove dead tissue?
leaves a cavity (6-8 weeks)
the characteristic microscopic feature of subacute infarct
macrophages
intracranial hemorrhages caused by trauma
intracranial hemorrhages caused by vascular pathology (and trauma)
epidural and subdural hemorrhages
intracerebral and subarachnoid hemorrhages
main causes of intracerebral hemorrhage
hypertension, cerebral amyloid angiopathy, vascular malformations, vasculitis (rare)
typical site of hypertensive hemorrhage
single, large hemorrhage in basal ganglia and thalamus, also in the pons
second most common cause of intracerebral hemorrhage
cerebral amyloid angiopathy (CAA) same amyloid as Alzheimer’s; tends to cause hemispheric hemorrhages
localized abnormal dilation of a blood vessel
aneurysm
types of aneurysms
saccular (berry)- spherical, involving portion of wall
atheroschlerotic (fusiform)- entire circumference of vessel
mycotic- infections, septic emboli
dissecting (rare)- through the wall of vessel
most common cause of non-traumatic bleeding in the subarachnoid space
saccular aneurysm
dissecting aneurysms typically occur
at the point where the internal carotid enters the cranium
types of vascular malformations, and which kinds are associated with hemorrhage
arteriovenous malformation and cavernous hemangioma are associated with hemorrhage
venous malformation and capillary telangectasis are not associated with hemorrhage
this malformation has a popcorn appearance on radiology
cavernous angioma
most common type of cerebral edema, and describe when it happens
vasogenic: fluid in extracellular space because of disruption of blood-brain barrier in infarct, hemorrhage, tumor, or trauma
describe what cytotoxic edema is and what causes it
fluid in intracellular compartment because of cellular membrane injury
hypoxia, metabolic event like ketoacidosis
sites of brain herniation
cingulate (subfalcine), uncal, tonsils of cerebellum, transcalvarial
transtentorial herniation compresses
occulomotor nerve, posterior cerebral artery; causes unilateral pupillary dilation and hemorrhagic infarct in occipital lobe
what is kernohan’s notch?
opposite side of brain stem is compressed against tentorium in a transtentorial herniation
duret’s hemorrhage is caused by
compression and pushing of brain stem in a transtentorial herniation
what happens to midbrain in transtentorial herniation?
anteroposterior elongation of midbrain
