Cerebrovascular Disease Flashcards
Global cerebral ischemia (diffuse hypoxic ischemic encephalopathy) occurs when there is a _____.
generalized reduction of cerebral perfusion
(due to blood lost due to trauma, surgery or shock)
Morphologic findings of global cerebral ischemia (3)
- Watershed (Border Zone) infarcts and laminar necrosis
- Necrosis of purkinje cells in the cerebellum OR of pyramidal neurons in the Sommer sector of the hippocampus
3 ways that a cell (neuron) can exhibit selective vulnerability for necrosis?
- They have a higher metabolic demand
- They release excessive amount of AA NT which can be toxic to post-synaptic neuron
- excitotoxicity
Global cerebral ischemia can lead to
Widespread neuronal death→ clinical brain death
Watershed (Border Zone) infarct occurs in the _____ (location)
Far end of the distribution of the anterior and middle cerebral arteries (it is poorly perfused where they meet)
(this leaves it likely to undergo infarction if it demands too much metabolically)
Define laminar necrosis
Necrosis that occurs in a lamina and spreads along the cerebral cortex
(these are affected first when there is a decrease in blood flow to the brain)
What is it?
Location of brain?
- Watershed or Border Zone infarct in a patient with global cerebral ischemia
- Parasagittal region of the hemisphere
(most common area for watershed infarct)
- Histological side of the cerebral cortex
- Arrows point to an area of laminar necrosis
Where is this most likely located?
This is likely a deeper area of the brain
Focal cerebral ischemia is an occlusion of the
Local blood supply (infarction)
Causes of focal cerebral ischemia
- Atherosclerosis
- Vasculitis
- Emboli
- Thrombus (especially patients with a hypercoagulable state)
What is the difference between nonhemorrhagic or hemorrhagic infarcts?
- Nonhemorrhagic (anemic) infarcts occur when due to an atherosclertic block→ occludes artery
- Hemorrhagic (red) infarct occurs when an embolus suddenly excludes the artery and lyses→ collateral vessels pre-perfuse→hemmorhage
(it is important to make the distinction between the two for medication)
Why is it important to make a distinction between a non hemorrhagic and a hemorrhagic infarct?
Thrombolytic medications = contraindicated in hemorrhagic infarcts
(we can make this distinction with an MRI)
Early on an infarcted area of focal cerebral ischemia is described as ____.
Soft and edematous
(encephalomalacia; malacia=softening)
Later on and infarct is phagocytized and a _____ is left.
cystic cavity is surrounded by gliosis
(there are no fibroblasts in the area to fill it in)
Hemorrhagic infarct in the temporal lobe
Non hemorrhagic infarct in the temporal lobe (oval)
Acute cerebral infarction
(note the red-neuron changes: pykanosis of nuclei and eosinophilic)
- Infarct at about 10 days exhibiting necrotic debris with infiltration by macrophages and surrounding reactive gliosis.
- Reactive gliosis can be seen in the lower right corner
- Brain tissue is liquefying
Small old infarct consisting of small cystic space accompanied by some surrounding gliosis
(8 weeks-years old)