Stroke, Bells Palsy, and Cerebral Edema (Exam 2)

Question 1

What is a stroke?

Answer 1

injury to the brain due to reduced blood flow either through ischemic or hemorrhagic conditions

Question 2

Where are the 4 common locations for a stroke?

Answer 2

1) hippocampus
2) cortex
3) cerebellum
4) brainstem

Question 3

What is hypoxia in the brain?

Answer 3

reduced oxygen in brain tissue

Question 4

What is ischemia?

Answer 4

transient or permanent interruption of blood flow

Question 5

What is an infarction?

Answer 5

irreversible brain tissue damage (cell death)

Question 6

What is a pernumbra?

Answer 6

“at risk” region of transition between necrotic tissue and the normal brain

Question 7

What are the 3 types of strokes?

Answer 7

1) ischemic (global or focal/localized)
2) hemorrhage
3) lacunar

Question 8

What is a global ischemic stroke?

Answer 8

-general reduction of blood flow to the entire brain
1) low oxygen levels in blood circulating in the brain (impaired oxygen carrying capacity (severe anemia or leukemia))
2) decrease perfusion (severe hypotension (acute shock))
3) complete lack of blood flow (cardiac arrest)
-severe global ischemia will result in widespread neuronal death
-survivors of severe global ischemic strokes remain in a persistent vegetative state and flat line indicating brain dead

Question 9

What does respirator brain mean?

Answer 9

long term use of mechanical ventilation will result in autolytic process of brain tissue and liquefaction

Question 10

What is a focal cerebral ischemic stroke?

Answer 10

-decreased or cessation of blood flow to a localized area of the brain due to an occlusion
-sustained ischemia leads to infarction
-extent of tissue damage caused by the stroke depends on the duration of the ischemia and the adequacy of collateral flow

Question 11

Which artery is the most common location for a focal cerebral ischemic stroke?

test q

Answer 11

middle cerebral artery

Question 12

What are the 2 types of a focal cerebral ischemic stroke?

test q

Answer 12

1) embolic (obstruction of an artery by something that traveled in the blood)
2) thrombotic (local formation of a thrombus within a vessel)

Question 13

What is an embolic stroke?

Answer 13

-blockage of an artery in the brain caused by an emboli
-blood clot, fat, plaque, air, or bony fragment travel in the blood and occludes a vessel distant from its origin

Question 14

What is a shower embolism?

boards q

Answer 14

fat embolism that occurs after fractures

Question 15

What are some causes of embolic strokes?

Answer 15

-heart disease
-MI
-post heart or lung surgery
-post long bone fracture
-a fib

Question 16

What is a thrombotic stroke?

Answer 16

-stroke caused by a thrombi/thrombus
-local development of a blood clot of plaque within the vessel
-does not travel, it occludes the lumen

Question 17

What are the most common sites for a thrombotic stroke?

Answer 17

-carotid bifurcation
-origin of middle cerebral artery
-either end of basilar artery

Question 18

What is a deep vein thrombosis?

Answer 18

thrombus that forms in the deep leg veins

Question 19

What are the risk factors for a thrombotic stroke?

Answer 19

-high BP
-high cholesterol
-diabetes mellitus
-atherosclerosis
-obesity
-smoking
-a fib
-sedentary lifestyle
-may be proceeded by “mini strokes” called transient ischemic attacks (TIA)

Question 20

What is a TIA?

Answer 20

-mini stroke caused by thrombus
-a warning sign for a potentially larger ischemic injury to the brain
-plaque reducing lumen of cerebral, carotid, or vertebral arteries
-sudden focal loss of neurological function with complete recovery within 24 hours
-can be asymptomatic

Question 21

What is a lacunar infarct?

Answer 21

-affects deep penetrating arterioles supplying basal ganglia
-caused by hypertension (arteriolar sclerosis)
-arterial lesions will occlude and cause small cavitary infarcts (lacunes)
-tissue loss of the subthalamic nucleus
-lakelike spaces (lacunae)
-can be silent or cause severe neurological impairment
-hemiballismus (unilateral chorea)

Question 22

What is a hemorrhagic stroke?

Answer 22

bleeding from vessels within the brain

Question 23

What is the most common cause of a hemorrhagic stroke?

Answer 23

ruptured aneurysm due to hypertension

Question 24

What are boarder zone infarcts or watershed infarcts?

boards q

Answer 24

-occur at the most distal reaches of the arterial blood supply
-border zones between arterial territories
-greatest risk is border zone between the anterior and middle cerebral artery (crescent shaped/sickle- shaped band of necrosis over the cerebral convexity)

Question 25

What are the clinical features for ischemic or hemorrhagic stroke?

Answer 25

sudden onset of: -unilateral weakness, numbness, or paralysis in the face and arm -slurred or garbled speech -dizziness or loss of balance or coordination -severe headache with no known cause -cognitive dysfunction

Question 26

What is bells palsy?

Answer 26

-unilateral facial paralysis or weakness not caused by stroke -no weakness or paralysis elsewhere -swelling, inflammation, or compression of CN VII (facial nerve) -one sided drooping of eyelid and corner of mouth -inability to wrinkle forehead -self limiting 2 weeks, many cases take longer or have repeat episodes

Question 27

What are the causes of bells palsy?

Answer 27

-sporadic -bacterial like lyme disease -viral like epsten barr (long latency can be 40-50 years later)

Question 28

What are the 3 layers of an artery?

Answer 28

1) tunica intima (endothelial tissue) 2) tunica media (smooth muscle) 3) tunica externa (connective tissue)

Question 29

What is a vertebral artery dissection?

Answer 29

-tear in the vessel causes an aneurysm and then hemorrhagic stroke or a blood clot and ischemic stroke -usually due to a trauma -can develop hours to days (rarely sudden unless theres a rupture)

Question 30

What is the order of a vertebral artery dissection pathogenesis? dragging test q

Answer 30

1) endothelial tear forms blood clot (embolic or thrombotic) 2) clot decreases lumen 3) limits blood flow 4) hypoxic conditions 5) stroke OR 1) endothelial tear causes aneurysm 2) subsequent trauma ruptures aneurysm 3) hypoxia 4) stroke

Question 31

What are the causes of a spontaneous vertebral artery dissection?

Answer 31

1) connective tissue disorders like marfan syndrome or EDS 2) atherosclerosis 3) trauma

Question 32

Who is high risk for a spontaneous vertebral artery dissection?

Answer 32

-chronic high BP -smoking -cardiovascular disease -obesity -long term contraceptives (20+ years)

Question 33

What are the general symptoms of a vertebral artery dissection?

Answer 33

-headache -neck and face pain -double vision -droopy eyelid -pulsatile whooshing sound in one ear -weakness on one side of face

Question 34

A vertebral artery dissection can be mistaken for what due to weakness on one side of the face?

Answer 34

bells palsy

Question 35

What is the red flag symptom of a vertebral artery dissection?

Answer 35

pulsatile whooshing sound in one ear

Question 36

What are the 4 types of cerebral edema?

Answer 36

1) cytotoxic edema 2) vasogenic edema 3) osmotic edema 4) interstitial edema

Question 37

What are the 2 types of cerebral edema post stroke?

Answer 37

cytotoxic edema or vasogenic edema

Question 38

Which cerebral edema is caused from over hydration and kidney damage?

Answer 38

osmotic edema

Question 39

Which cerebral edema is caused by high BP and high intravascular pressure?

Answer 39

interstitial edema

Question 40

What is cytotoxic edema? test q

Answer 40

-begins immediately post stroke -decrease in oxygen decreases ATP and the sodium potassium pumps stop working so cells swell -intracellular sodium builds up -water in ECF flood into neuron to balance our sodium -neuron swells so much it will die by rupturing -sodium and calcium pumps will also stop working which causes intracellular calcium to build, glutamate will be released and cause excitotoxicity (too much intracellular calcium causes even more cell death) -neuron can be saved if oxygen levels rise to permit aerobic ATP production

Question 41

What is vasogenic edema? test q

Answer 41

-occurs 4-6 hours post stroke and can go on for days -ischemic conditions and inflammation will break down BBB -endothelial cells, basal lamina, and tight junctions become leaky -astrocytes break down and are no longer supporting the blood vessels -ECF inside blood vessel leaks out between tight junctions (some of this fluid adds to the cytotoxic edema and some builds up causing displacement or herniation of brain tissue)

Question 42

What is osmotic edema?

Answer 42

-caused by hyponatremia (over hydration) -cells swell and can rupture, similar to cytotoxic edema because of an imbalance of sodium

Question 43

What is interstitial edema?

Answer 43

-caused by abnormally high intravascular pressure, high BP, and high atmospheric pressure -the increased pressure pushes too much fluid through the choroid plexus in the ventricles which then pushes CSF across the ependymal lining of the ventricle into brain tissue

Question 44

What is hydrocephalus?

Answer 44

-accumulation of CSF within the ventricles -caused by impaired CSF flow and reabsorption -in the adult, ventricles will enlarge if CSF cannot drain -brain tissue is damaged by compression -head will enlarge in an infant prior to closure of sutures, if CSF cannot drain