Cerebrovascular diseases

Question 1

List the mechanisms by which hypoxia (deprivation of O2) can occur by

Answer 1

low level of oxygen in blood
low blood flow to tissue-ischemia
oxygen utilization by tissue is impaired

Question 2

What is the definition of ischemia?

Answer 2

low blood flow

Question 3

When does global ischemia to the brain occur?

Answer 3

systolic BP <50

Question 4

When does focal ischemia in the brain occur?

Answer 4

during obstruction of local blood supply, leads to infarction

Question 5

What area of the brain does global ischemia impact first?

Answer 5

borderzone/watershed areas

low flow areas between anterior, middle and posterior cerebral arteries

Question 6

List the cell types in decreasing order of oxygen deprivation sensitivity

Answer 6

neurons, oligodendrocytes, astrocytes

Question 7

List the brain regions in decreasing order of oxygen deprivation sensitivity

Answer 7

hippocampus (CA1 sector-sommer sector)
Lamina 3 & 5 of cerebral cortex (laminar necrosis)
purkinje cells in cerebellum

Question 8

What role does glutamate play during ischemic/hypoxic injury?

Answer 8

when present in excess is neurotoxic, is commonly present in excess during ischemic/hypoxic injury

Question 9

What determines the selective vulnerability of different cells/regions?

Answer 9

variable O2/energy requirements of different neurons and neuronal populations

Question 10

What histologic changes occur to acutely hypoxic/ischemic neurons?

Answer 10

“red is dead”
pyknotic cells with shrunken and dark nucleus, no nucleolus visible
red cytoplas w/ no missl substance visible

Question 11

What are the outcomes of severe global ischemia?

Answer 11

widespread neuronal death, irrespective or regional vulnerability
leads to persistent vegetative states and/or brain death

Question 12

How is brain death defined?

Answer 12

diffuse cortical injury with brainstem injury (absent reflexes and respiratory drive)

Question 13

What are the findings of severe global ischemia (respirator brain) on autopsy?

Answer 13

swollen brain, slit like ventricles, herniation

collapsed vessels due to swelling

Question 14

What are the 3 major causes of focal ischemia?

Answer 14

thrombosis (atherosclerosis)
emobli
lacunar infarcts/slit hemorrhages

Question 15

Where does thrombosis/atherosclerosis most commonly cause focal ischemia?

Answer 15

carotid bifurcation
origin of MCA
origin or end of basilar artery

Question 16

What type of infarct do emboli commonly cause?

Answer 16

hemorrhagic infarct

Question 17

What are cardiac sources of emboli?

Answer 17

mural thrombi

endocarditis (bacterial or marantic emboli)

Question 18

What are non cardiac sources of emoli?

Answer 18

atheromas

fat, neoplasms, air

Question 19

Which vessel is most commonly affected by emboli?

Answer 19

MCA

Question 20

What causes lacunar infarcts/slit hemorrhages?

Answer 20

hyaline arteriolosclerosis caused by hypertension and diabetes mellitus

Question 21

What are lacunes?

Answer 21

small stroked in subcortical brain structures that may be hemorrhagic

Question 22

What are uncommon causes of brain infarction?

Answer 22

vasculitis
arterial dissection of carotid arteries
coagulation disorders
microvasculopathy
amyloid angiopathy
drug abuse

Question 23

What are the characteristics of primary angiitis (vasculitis) of the CNS?

Answer 23

involves multiple small/medium sized meningeal and parenchymal vessels
chronic inflammation, fibrinoid necrosis, multinucleated giant cells, wall destruction

Question 24

What does acute infarct look like on gross examination?

Answer 24

soft, swollen, grey-white distinction blurred

up to 48 hrs post infarct

Question 25

What does subacute infarction look like on gross examination?

Answer 25

liquefactive necrosis | 2-3 wk post infarct

Question 26

What does chronic infarction look like on gross examination?

Answer 26

cavitated, all dead tissue removed | several months post infarct

Question 27

What does acute infarct look like on microscopic exam?

Answer 27

red neurons, pallor | possibly neutrophils

Question 28

What does subacute (organizing) infarct look like on microscopic exam?

Answer 28

macrophages, necrotic tissue, reactive astrocytes, vascular proliferation

Question 29

What does chronic infarct look like on microscopic exam?

Answer 29

cavilty with glial scar

Question 30

What are the signs and symptoms of vascular dementia?

Answer 30

pattern of damage samll areas of infarct/multiple lacunar infarcts diffuse white matter disease infarct occur in areas important for cognition/memory

Question 31

What does cerebral venous thrombosis cause? Where?

Answer 31

hemorrhagic infarcts | superior sagital and/or lateral sinuses (results in parasagitall hemorrhagic infacts)

Question 32

What are some causes of central venous thrombosis?

Answer 32

infection, injury, neoplasm, surgery, pregnancy OCPs, hematologic abnormalities, dehydration, malignancy

Question 33

What are causes of intracerebral hemorrhage?

Answer 33

hypertension (MCC) vascular malformations amyloid angiopathy

Question 34

What are key features of HTN induced ICH?

Answer 34

abrupt onset of severe neurologic dysfunction when hematoma is large putamen, thalamus, pons, cerebellum commonly affected hyaline arteriolosclerosis

Question 35

What is the most common type of vascular malformation?

Answer 35

arteriovenous malformation: tangled network of vessels with AV shunt

Question 36

What are other, less common types of vascular malformations?

Answer 36

capillary telangiectasia cavernous angioma venous angioma

Question 37

What are causes of lobar hemorrhage?

Answer 37

``` neoplasms drug abuse vasculitis hemorrhagic diathesis amyloid angiopathy ```

Question 38

What are common causes of subarachnoid hemorrhage?

Answer 38

trauma | aneurisms

Question 39

What are 3 common types of CNS aneurisms

Answer 39

saccular (berry) mycotic (fungus) fusiform/atherosclerotic

Question 40

What are key features of saccular/berry aneurism?

Answer 40

"the worst head ache i've ever had" (w/rupture) increased risk w/ HTN, smoking, AVM, etc increased risk of rupture as size increases not present at birth, but hte defect in the media is congenital and the aneurism develops over time usually occurs at branch points in the anterior circulation (ant communicating and anterior cerebral junction most common location)

Question 41

What is a stroke?

Answer 41

a sudden failure of brain function due to diminished blood flow to a part of the brain, or due to bleeding inside the brain

Question 42

What are 5 major signs of a stroke?

Answer 42

``` hemineglect vision loss loss of speech or comprehension numbness on one side weakness on one side ```

Question 43

What does complete lack of blood flow result in?

Answer 43

cortical laminar necrosis

Question 44

What does low blood flow result in?

Answer 44

watershed injury

Question 45

What causes arteriovenous malformations?

Answer 45

atherosclerosis congenital prone to develop in cocain users more common in HTN patients