Cerebral Vascular Diseases

Question 1

In stroke symptoms are usually on both sides of the body. True/false?

Answer 1

False. In stroke, symptoms are usually on one side of the body eg arm weakness, face drop is dichotomized due to crossing in the brain

Question 2

Motor symptoms in stroke are experienced due to a crossing in which tract?

Answer 2

Pyramidal tract

Question 3

Name 6 symptoms of stroke

Answer 3

Hemiparesis(motor deficit)
Dysarthia- abnormality in speech articulation
Dysphagia- difficulty in swallowing
Aphasia- inability to understand a word. Sing but not talk
Sensory deficit
Ataxia
Visual disturbance- problem in right occipital cortex-left hemianopia, CRAO-stroke of the eye
Headache
Impaired consciousness

Question 4

Match  the artery to the symptom
Anterior cerebral artery
Middle cerebral artery
Posterior cerebral artery
Posterior circulation

Answer 4

Anterior cerebral artery- hemiparesis (lower extremity), apraxia
Middle cerebral artery - hemiparesis (upper extremity)
Posterior cerebral artery-visual, thalamic, memory
Posterior circulation-brain stem syndromes eg oculomotor

Question 5

What is a transient ischemic attack ie TIA?

Answer 5

Brief, majority less than 15 minutes, max 24 hr episodes of focal loss of brain function due to ischemia

Question 6

What are the symptoms of a TIA?

Answer 6

No persistent deficit
abrupt onset of hemideficit(paresis, numbness), slurred speech, difficulty to understand, loss of consciousness
50% demonstrate DWI abnormalities
CT/MRI may reveal abnormalities
Every third stroke heralded by a TIA
Annual risk of stroke during first 5 years at 5%

Question 7

In the case of a TIA would you administer TPA?

Answer 7

no, because tissue plasminogen activator is administered to reopen a blocked vessel

Question 8

What are examples of cererbral vascular diseases?

Answer 8

Ischemic stroke 85%- atherothrombotic, cardioembolic, microangiopathic
Subarrachnoid hemorrhage 10%
Primary intracerebral hemorrhage 5%

Question 9

Which treatments of acute ischemic stroke have proven efficacy?

Answer 9

1. Thrombolysis 
Stroke Unit
Thrombolysis with rtPA (recombinant tissue plasminogen activator) i.v within 4.5 hours of symptom onset and exclusion of hemorrhage
Endovascular treatment within 6 hours
2. Thrombectomy

Question 10

Thrombolysis is the only clinically proven treatment for ischemic stroke. True or false

Answer 10

True

Question 11

Define thrombectomy

Answer 11

When a stent is inserted into a blood vessel to remove a clot. Clot is caught in stent and removed

Question 12

What is a stroke unit?

Answer 12

A specialized facility for thrombolysis, checking body temperature, blood pressure, glucose, oxygenation levels to monitor and treat complications

Question 13

more men than women can expect to suffer from stroke. True/false

Answer 13

True. 25% men Vs 20% of women by age 85

Question 14

Ischemic stroke is a syndrome and not a single disease state. True/false

Answer 14

True

Question 15

List some common unavoidable risk factors of stroke

Answer 15

age, gender, race, other genetic factors

Question 16

List some common modifiable risk factors of stroke

Answer 16

Hypertension, smoking, diabetes

Question 17

What are some secondary prevention methods of stroke?

Answer 17

300 mg asprin, clopidrogrel/ dipyridamol + ASS
cardiac embolism: anticoagulation
treat hypertension
quit smoking
statins with CHD/hypercholesterinemia
Carotid-TEA if stenosis is more than 70%

Question 18

Define a Penumbra

Answer 18

Pene (near), umbra (shadow). Regioin of silence in electrical activity but with preserved metabolism (electrophysiological/morphological)

Question 19

Name two features of a penumbra

Answer 19

decreased blood flow, increased oxygen extraction (misery perfusion PET)
tissue at risk
reduced prerfusion, normal diffusion MRT

Question 20

What is the main principle of diffusion weighted imaging?

Answer 20

Diffusion of protons between Intracellular volume (low ADC) and extracellular volume (high ADC). ADC is the apparent diffusion coefficient and decreases by about 30-50% in the case of ischemia due to cells swelling hence lower proton conc in extracellular

Question 21

How does ischemia lead to cell death

Answer 21

As a result of ischemia, cells are deprived of substrate , which causes an energy deficit due to decreased ATP in the cells, therefore leading to cell death

Question 22

What is the difference between a functional and structural lesion?

Answer 22

For an ischemic penumbra to occur, at the core, there is a structural lesion in which cells will die. A functional lesion is the penumbra where neurons are no dead but cells are arrested

Question 23

What does MR measure?

Answer 23

MR measures the spinning of proton molecules

Question 24

What happens to neurons that are low in energy?

Answer 24

Neurons low in energy will depolarize, release glu into ECM, receptors in ECM sense glu that is massively released, calcium entry, sodium entry, radicals, water enters cells, cells swell, potassium released leading to spread in depol, ECM shrinks….apoptosis

Question 25

Name two depolarizing agents in the case of low energy neurons durign excitotoxicity.

Answer 25

Potassium and glutamate. Potassium is released causing spread in depolarization. Glu and K diffuse into the penumbra and into neighbouring cells.

Question 26

In the pathobiology of stroke, name events that take place within minutes

Answer 26

Damage: Energy failiure,
Protection: Endogenous neuroprotection

Question 27

In the pathobiology of stroke, name events that take place after hours into days/ weeks

Answer 27

Damage: secondary damage eg inflammation and apoptosis
Protection: Repair regeneration

Question 28

During excitotoxicity, what substrate is blocked?

Answer 28

Glucose entry, oedema

Question 29

How does spreading depolarization occur

Answer 29

A series of depolarizations preceed spreading. When neurons are low in energy, release glu ie depolarize easily. Enry of sodium and water, cells swell.Depolarizing agents such as K and glu are released after cells swell causing peri-infract depolarizations/ spread in depolarization as the ions diffuse into the penumbra and into neighbouring cells

Question 30

What molecules are involved in excitotoxicity and which ones would be used for anti-excitotoxicity that takes place within minutes

Answer 30

Excitotoxicity: glutamate, calcium, OFR

Anti-excitotoxicity:GABA, adenosine, Katp activation

Question 31

Which molecules are involved in inflammation/apoptosis and anti-inflammation/apoptosis (hours)?

Answer 31

Inflammation/apoptosis: IL-1,COX-2, MMPs, caspases

Anti: IL-10, EPO (erythropoietin)

Question 32

What occurs during repair and regeneration during protection?

Answer 32

scar formation, vasculogenesis, neurogenesis, BM-derived cells, sprouting

Question 33

How does stroke injury induce immunosupression?

Answer 33

After CNS injury, there is release of immune modulators from blood vessels, nerves, adrenal glands. eg NE, glucocorticoids, acetylcholine. Leads to apoptosis of neutrophils, killing of t helper cell type 1, and upregulate t helper cell type 2.
Overall effect: immunodepression

Question 34

How does stroke induce changes in the metabolic system?

Answer 34

Paresis/stress/CNS local damage leads to impaired signalling/neuroendocrine activation/local inflammation that leads to increased catabolic signals and decreased anabolic signals