3.21.14 39 Vasculopathology Flashcards
What’s the difference between hypoxia and ischemia?
Ischemia = loss of circulation
Hypoxia = decreased oxygen
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Ischemia always leads to hypoxia, but not all hypoxia = ischemia
What’s an infarct?
Death of tissue
What are the causes of ischemic infarct?
Atherosclerosis
Thrombosis
What is the cause of hemorrhagic infarct?
Incomplete occlusion followed by recirculation:
Vessels become weak, reperfusion leads to hemorrhage
What is the difference between hemorrhagic infarct and primary hemorrhage?
Primary hemorrhage is not preceded by infarct; brain tissue is displaced (hematoma)
What is the progression of an infarct (tissue changes)?
Within 24 hrs: acute neuronal injury >24hrs: infarction 1st week: neutrophils 2-3 weeks: macrophages replace neutrophils Gradual gliosis 6-8 wks: cavity formation
Myocardial infarcts, ruptured aortic aneurysms, and GI bleeds can lead to what type of CNS problem?
Generalized/global ischemia and hypoxia
What is the characteristic appearance of ischemic neurons?
Red neurons
What two areas are most sensitive to ischemia?
Sommer’s sector (CA1) of hippocampus
Purkinje cells
What is laminar necrosis? What characterizes this microscopically?
Watershed infarcts - typically targets cortical layers 3,5,6 (pyramidal cells)
Band-like pattern of necrosis –> areas near the surface are protected by the meninges
What defines brain death relative to persistent vegetative state?
Flat EEG
Absence of perfusion, reflexes, respiration
What is respirator brain?
Autolysis of brain tissue when pt is kept alive on mechanical ventilation - soft, liquefied brain tissue
Why shouldn’t tPA (fibrinolytic treatment) be given after 3 hrs?
Danger of hemorrhagic infarction: reperfusion can rupture damaged blood vessels
Atherosclerosis and thrombosis typically lead to…
Ischemic infarction
Embolism, vasospasm, extrinsic compression, and reperfusion typically lead to…
Hemorrhagic infarction
Trauma usually leads to what types of hemorrhage?
Epidural and subdural
Vascular pathology usually leads to what types of hemorrhage?
Intracranial and subarachnoid
Hypertension can cause what types of brain bleeds?
Intracerebral and cerebral hemorrhage
Berry aneurysms lead to what types of brain bleeds?
Subarachnoid
What types of vascular malformations can lead to hemorrhage?
Arteriovenous malformations
Cavernous hemangiomas
What are arteriovenous malformations?
Thick arteries and veins without capillary channels
What is a cavernous hemangioma?
Dilated, intercommunicating veins without brain tissue in between
What are dissecting aneurysms?
Atherosclerotic damage leads to cracks in the intima –> blood seeps through, widening the cracks
What is vasogenic edema?
Most common cerebral edema
Fluid in extracellular space (white matter only)
Disruption of BBB in infarct, hemorrhage, tumor, trauma
What is cytotoxic edema?
Fluid in intracellular space (white and gray matter)
Cellular membrane injury due to hypoxia or metabolic events
What herniation occurs when brain tissue crosses under the cerebral falx?
Cingulate/subfalcine
What herniation occurs when tissue from the temporal lobe gets compressed within the tentorial notch?
Uncal/transtentorial
What herniation occurs when the cerebellum gets compressed in the foramen magnum?
Tonsillar
What herniation occurs when brain tissue leaks out the skull?
Transcalvarial/fungating
Secondary hemorrhage in the brain stem occurs due to compression following what herniation? What is this hemorrhage called?
Transtentorial/uncal
Duret hemorrhage
