CVA I: Intro to CVA

Question 1

Definition of CVA

Answer 1

Acute Onset of neuro dysfunction resulting from an abnormality of cerebral blood flow that lasts for 24 hours or results in death within that 24 hours.

Question 2

2 Mechanisms of CVA? Which one is more common?

Answer 2

Ichemia: Lack of Blood: Thrombus, embolus, or condition that results in low perfusion pressures.
Hemorrhage: rupture of vessel causing bleeding into brain tissue.
Ichemic strokes much more common (87% of all strokes).

Question 3

Do women or men have more strokes and why?

Answer 3

Women (60% of CVA’s) because they live longer and stroke happens more in older persons.

Question 4

CVA’s are the ____ leading cause of death in the US and the ____ leading cause of disability in the US.

Answer 4

3rd leading cause of death

1st leading cause of disability

Question 5

Who has the greater risk of stroke, blacks or whites?

Answer 5

blacks (2x higher rate than whites)

Question 6

What is the primary risk factor for Ischemic Strokes?

Answer 6

Atherosclerosis (Formation of plaques in tunica intima of arteries).

Question 7

What are the two causes of interruptions to blood flow in atherosclerosis?

Answer 7

1. Turbulent blood flow causes platelets to form clot at site of atheroma.
2. Piece of thrombus breaks off anywhere in body (embolus) and travels to narrow spot in cerebral vasculature, from CVD, DVT, or fat, tumor, or air emboli.

Question 8

Which type of hemorrhagic stroke is more common, intracerebral or subarachnoid?

Answer 8

intracerebral (~3x more common)

Question 9

What are two factors that can cause hemorrhagic strokes?

Answer 9

1. Atherosclerotic plaques

2. Developmental abnormalities

Question 10

What are 2 developmental abnormalities that can cause hemorrhagic stroke?

Answer 10

1. Berry Aneurysms (weak spot on arterial wall).
2. Arteriovenous Malformations (AVM)
   - Tangle of arteries & veins c no capillary system between them, which can dilate and weaken over time, rupturing in 50% of cases.

Question 11

What are the 6 Modifiable factors for strokes listed in the notes?

Answer 11

1. HTN
2. CVD: CHD, CHF, Valvular, Arrythmias, cardiac sx
3. Diabetes
4. TIA’s
5. Hyperlipidaemia
6. Smoking

Question 12

What are 5 NONmodifiable factors for strokes listed in the notes?

Answer 12

1. race (blacks have ^ risk)
2. ^ Age
3. gender (male)
4. heredity
5. previous stroke

Question 13

What are the signs/symptoms of CVA?

Answer 13

1. Sudden severe headache of unknown cause.
2. Sudden weakness or numbness of face or extremity on one side.
3. Sudden dimness or loss of vision, especially in one eye.
4. Unexplained dizziness, unsteadiness, or sudden falls (especially if accompanied by other symptoms)

Question 14

What is the area of living, but metabolically lethargic cells surrounding the brain infarction called?

Answer 14

Penumbra

Question 15

What NT is largely responsible for cascades of chemical activity that occurs with infarction that causes further damage to cells? What is the mechanism?

Answer 15

glutamate (causes Ca influx into neurons which activate Ca-dependent enzymes that destroy cells).

Question 16

What is the most frequent cause of death in acute CVA?

Answer 16

Edema causing herniated brain tissue caudally (brainstem herniation) or contralaterally (midline shift). Can cause more ichemia and further cell death.

Question 17

What are the 3 factors that determine symptoms of stroke?

Answer 17

1. Location of ichemia or hemorrhage.
2. Size of infarction
3. Presence of collateral circulation.

Question 18

What are “Lacunar” infarcts?

Answer 18

Small infarcts (<15mm in diameter) that result from occlusion of small penetrating arteries damaged by chronically elevated arterial BP. If these hit important area or if multiple ones happen, can cause significant problems.

Question 19

Anterior Cerebral Artery Syndrome results in damage to what potential 5 areas of the brain?

Answer 19

Primary motor cortex
internal capsule
primary sensory cortex
superior frontal gyrus
corpus callosum

Question 20

Anterior Cerebral Artery Syndrome causes more trouble in the LE or UE? Why?

Answer 20

LE > UE because homunculus for LE’s is closer to this artery.

Question 21

Damage to the Superior frontal gyrus causes what symptom? Damage to corpus collosum?

Answer 21

sup. frontal: urinary incontinence

corpus: difficulty with imitation and bimanual tasks, apraxia.

Question 22

Middle Cerebral Artery Syndrome causes problems in what 9 areas of the brain? What problems does it cause in each area?

Answer 22

1. Primary motor cortex (paresis in contralateral face, UE, and LE (least in LE b/c homunculus)).
2. internal capsule (sensory & motor)
3. primary sensory cortex (sensory impairments)
4. Broca’s area (Expressive aphasia)
5. Wernicke’s area (Receptive aphasia)
6. Sensory association cortex (Perceptual deficits)
7. Optic radiation in internal capsule (homonymous hemianopsia)
8. Frontal eye fields or descending tracts (lateral eye movements - loss of conjugate gaze to opposite side).
9. Parietal lobe (Ataxia of contralateral limbs (sensory).

Question 23

Posterior Cerebral Artery Syndrome (PERIPHERAL territory) causes problems in what 4 areas and what symptoms does it cause?

Answer 23

1. Primary visual cortex or optic radiation (contralateral homonymous hemianopia).
2. Visual association cortex (Prosopagnosia - can’t recognize faces).
3. Dominant calcarine lesion and posterior part of corpus callosum (dyslexia without agraphia).
4. Inferomedial temporal lobe (memory deficits).

Question 24

Posterior Cerebral Artery Syndrome (CENTRAL territory) causes problems in what 4 areas and what symptoms does it cause?

Answer 24

1. VPL of thalamus (thalamic syndrome (sensory problems and horrible pain).
2. Subthalamic nucleus (involuntary mvmts)
3. Cerebral peduncle in midbrain (Contralateral hemiplegia).
4. CN III and cerebral peduncle in midbrain (Weber’s syndrome).