Neuro 2 Flashcards
(198 cards)
Cerebrovascular disease
Brain injury hemorrhagic ischemic
Ischemia
Reduced perfusion
Loss of ATP and membrane potential for electrical activity
Increased cytoplasmic Ca-cytotoxic
Excitotoxicity-inappropriate release of excitatory aa
Glutamate-ca through NMDA cytotoxic
Penumbra
Area of at risk tissue at region of transition between necrotic tissue and normal brain
- rescued with anti apoptotic
- ischemia may cause apoptosis
Are embolisms or thrombosis more common
Embolism
Global cerebral ischemia (diffuse ischemic/hypoxic encephalopathy)
Generalized decrease renal perfusion
Can be minor or severe
What causes global cerebral ischemia
Cardiac arrest, shock, severe hypertension
What cells are most sensitive to global cerebral ischemia
Neurons , glial
Pyramidal cells of hippocampus CA1 sommer
Cerebellar purkinje and neocortex bets
Pseudolaminar necrosis
Band like pattern cells remain next to meninges
Due to some cells being more sensitive
Symptoms of global cerebral ischemia
Total loss of brain function
Patients who survive often are in persistent vegetative state brain dead and brainstem damage
When left on respirator with undergo respirator brain-autolytic processs with gradual liquefaction
Border zone (watershed) infarcts
Distal brain or spine or arterial supply, the border between arterial territories
What border zone is most vulnerable to infarct
Between ACA(legs and dick) and MCA (convexities)
Linear para sagittal infarction
Area of cortex is most at risk and will show a sickle shaped band of necrosis over the cerebral convexities a few cm lateral to the interhemispheric fissure
Why are areas in watershed areas between ACA and MCA most vulnerable
Large pyramidal neurons in particular are most sensitive to hypoxic and hypoglycemic stress
When are border zone watershed infarcts seen
Hypotensive episodes
Morphology of global ischemia
Edema and swollen brain wide gyri narrow sulci
Ongoing liquefication necrosis
Demarcation bt white and grey
12-24 hours-red neuron
2 weeks-necrosis, macrophages, vascular proliferation, gliosis
After-macrophages, remove necrotic tissue, loss of architecture, gliosis
Pseudolaminar necrosis-neuronal loss and gliosis uneven in cortec some layers preserved some not
Fibroblast proliferation rare
Focal cerebral ischemia
Reduction or cessation or blood flow to localized area
Sustained get infarction
Damage depends on collateral
Where is there no collateral circulation
Deeper areas and white matter
Thalamus, basal ganglia, deep white
Embolism
From cardiac mural thrombi
plaque in ICA go to MCA
Where do most embolism events occur
Gray white junction where narrowing and acute branching of the vessels trap emboli
MCA location
Supplies convexities of cortec arms and feet on homunculus
What artery is most frequently affected by embolism infarction
ICA send to MCA
Shower embolism(like fat emboli after bone break)
Generalized cerebral dysfunction with higher cortical function disturbance and consciousness
Widespread white matter hemorrhages -characteristic of embolization of bone marrow after trauma
Thrombotic occlusion
Usually from atherosclerosis and plaque rupture
Most common sites of thrombotic occlusions
Carotid bifurcation, origin of MCA and either end of basilar artery
Thrombi
Progressive narrowing may cause fragmentation