Neurovascular disorders (done) Flashcards

1
Q

What is a stroke?

A

Acute onset of neurological deficits (lasting more than 24hrs due to a disturbance in blood supply

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2
Q

How many ppl suffer from strokes each year?

A

Approx 15 million

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3
Q

What are the 2 categories of risk factors for a stroke?

A
  • Non-modifiable
  • Modifiable
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4
Q

What are the modifiable risk factors of a stroke?

& how much can some inc chances by?

A
  • Hypertension (high BP)
  • Diabetes
  • Hyperlipidemia (high cholesterol)
  • Smoking = 50% inc
  • Obesity = 3x inc
  • Carotid artery disease
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5
Q

What are the non-modifiable risk factors of a stroke?

(Give specifics for some pls)

A
  • Age (avg 68-73)
  • Atrial fibrillation
  • Gender
  • Ethnicity
  • Family history
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6
Q

How can gender affect the chances of having a stroke?

A

Women are less likely until menopause

The strokes that occur during menopause tend to be worse

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7
Q

Why is it so important to understand strokes?

A

It is the 3rd largest cause of death

15 million ppl suffer a stroke each year:
1/3 will die, 1/3 recover & 1/3 have lasting effects

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8
Q

What are the 2 main divisions of strokes?

How common is each type?

A

Ischemic (85%)

Haemorrhagic (15%) = least common type

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9
Q

What is a Haemorrhagic stroke?

A

Bleeding in the brain from ruptured blood vessel –> there are 2 types

(Some more context = Deprives brain cells of O2 & nutrients - damaged cells can’t func = lasting damage)

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10
Q

What are the 2 types of Haemorrhagic stroke?

How common are each of them?

A
  • Intracerebral - 10%
  • Subarachnoid - 5%
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11
Q

What is an intracerebral stroke (haemorrhage)?

A

A type of Haemorrhagic stroke (the more common type)

Bleeding occurs within brain tissue itself

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12
Q

What is a a subarachnoid stroke (haemorrhage)?

A

A type of haemorrhagic stroke (less common type)

Bleeding occurs between brain & subarachnoid space

These are rarer than intracerebral but are more devastating

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13
Q

What are the 2 types of ischemic stroke?

How common is each type?

A
  • Thrombotic - 55%
  • Embolic - 30%
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14
Q

What is an ischemic stroke?

A

The blood supply to the brain is blocked or stopped

Can be caused by blood clots or artery narrowing

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15
Q

What is an thrombotic stroke?

A

The more common type of an ischemic stroke (55%)

Caused by a blood clot (thrombus) formed in the arteries supplying blood to the brain

Blockage cuts off blood flow = stroke

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16
Q

What is an embolic stroke?

A

The less common type of an ischemic stroke (30%)

Caused by a blood clot (embolus) formed ELSEWHERE in the body & travels to block an artery supplying blood to the brain

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17
Q

What is the difference between a lacunar occlusion & a large vessel occlusion

A

Lacunar occlusion

  • Blockage of small arteries deep in the brain tissue
  • Can be caused only by thrombotic stroke

Large vessel occlusion

  • Blockage in major artery of the brain
  • Can b caused by either thrombotic or embolic stroke
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18
Q

What are the 4 areas that symptoms of a stroke can arise from?

A
  • Haemorrhage
  • Anterior circulation
  • Posterior circulation
  • Non-specific symptoms
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19
Q

What are the symptoms of a haemorrhage?

A
  • Thunderclap headache
  • Seizures
  • Nausea
  • Unilateral weakness
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20
Q

What type of stroke is anterior circulation most common in?

A

An ischemic stroke (70%)

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21
Q

What are the symptoms of anterior circulation issues in a stroke?

A
  • Hemiplegia (paralysis)/paresis (weakness) of one side of body
  • Hemisensory loss (loss of sensation)
  • Dysphasia (difficulty producing/understanding words)
  • Aphasia (same as above)
  • Hemianopia (partial loss of vision)

(Most commonly seen in ischemic stroke)

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22
Q

What are the symptoms of posterior circulation in a stroke?

A
  • Unilateral limb weakness (weakness one side of body)
  • Ataxia (lack of voluntary coordination of muscles movement)
  • Dysarthria (difficulty forming & pronouncing words)
  • Hemianopia - isolated (vision loss)
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23
Q

What are the non-specific symptoms of a stroke?

A
  • Confusion, drowsiness, dizziness
  • Nausea, double vision
  • Incontinence
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24
Q

What symptom can indicate to us in isolation that a posterior circulation stroke is occurring?

A

Hemianopia (loss of vision in both eyes)

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25
Q

What happens in the brain in a lacunar infarction?

A

Small, strategic strokes happen in penetrating arteries that feed sub-cortical structures

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26
Q

What % of lacunar infarctions are silent?

A

As many as 80% are clinically silent

27
Q

What is motor hemiplegia syndrome?

What type of infarction is it?

A

Infacrtion in the internal capsule, basal ganglia &/or pons

A lacunar infarction

28
Q

Why can lacunar infarctions be just as devastating, even though they’re only small strokes?

A

Many occur in the basal ganglia & internal capsule (motor hemiplegia syndrome)

These are major movement areas –> so can cause huge issues

29
Q

What can cause stroke symptoms to vary?

A
  • The blood vessel involved
  • The size of the lesion
  • The region of the brain affected (anterior or posterior circulation)
30
Q

What is the most common stroke?

What does it result in?

A

Middle cerebral artery infarction

Results in contralateral hemiplegia & hemiosensory loss

31
Q

How are strokes identified?

A

A neurological examination is followed by urgent referral for neuroimaging

Neuroimaging generally done by CT (computed tomography) –> this can detect haemorrhage

32
Q

What is the issue with using CT scan to detect strokes?

A

It is not as effective at detecting acute ischemic stroke (can see it slightly as the sulci become less defined

Good for hemorrhagic strokes tho

33
Q

What % of ppl who have a brain haemorrhage die?

A

45%

34
Q

What is vasospasm & what is the chance of getting this from a haemorrhage?

A

Blood vessels (once haemorrhaged) start to spasm & constrict

This can result in an ischemic stroke

35
Q

How is a brain haemorrhage treated?

(Must be treated as brain haemorrhage won’t treat itself

A

Treatment involves:

  • Pain management
  • Surgery to repair the bleed using clipping or coiling
  • This may include lowing BP
36
Q

What happens when a blood vessel is clipped?

A

Small metal clip placed at the base to block blood flow & clip the vessel

37
Q

How is coiling used to treat a haemorrhage?

A

Inject an opaque dye into blood vessels to see the problem area

They fill the aneurism with wires & this stops blood flowing out more

This is done as blood vessel is hard to reach

38
Q

What is the first treatment used when someone has an ischemic stroke?

A

Thrombolysis using TPA (tissue plasminogen activator)

Brand normally used = Altepase

39
Q

How soon does thrombolysis using TPA need to be given after an ishcemic stroke?

A

Given within 3-4.5 hours

(Has been shown to work after 6 hours tho)

40
Q

What is the other option to treat ischemic stroke after Thrombolysis?

A

If TPA hasn’t worked:

A Thrombectomy –> a retriever device removes the clot

41
Q

How long after the stroke must a thrombectomy be performed?

A

Within 6 hours of the stroke

(If TPA hasn’t worked)

42
Q

What are the 4 areas involved in the concept of the penumbra?

A
  • Core
  • Penumbra
  • Benign oligemia
  • Normal tissue
43
Q

During a stroke how much blood flow is the following regions getting?

A
  • Core = <12mL/100g/min
  • Penumbra = 12-22mL/100g/min
  • Benign oligemia = >22mL/100g/min
  • Normal tissue = 50-54mL/100g/min
44
Q

What is the importance of the penumbra?

A

The penumbra is the area surrounding the core region of the stroke

Cells in the core are already dead (lack of blood flow = lack of O2 = loss of func)

Penumbra has reduced but not absent blood flow –> cells have not yet died

45
Q

If a stroke is treated quickly what happens to the penumbra?

A

The blood flow can return to the cells & they can be saved & regain function

IF not treated quickly these cells may die along with the core

46
Q

What are the 4 stages in the time course of events in a stroke?

When do these events occur?

A
  • Excitotoxicity = minutes (decreases at hours)
  • Peri-infarct depolarisations = same as above
  • Inflammation = Hours - days
  • Apoptosis = hours - days (inc more at days)
47
Q

What is excitotoxicity in a stroke?

A

During stroke, excessive release of glutamate = excitotoxicity

This is what kills a lot of the cells

48
Q

What are peri-infarct depolarisations in a stroke?

A

PIDs are waves of neuronal & glial depolarisation that propagate thru the penumbra & sometimes into healthy brain tissue

49
Q

What effect to peri-infarct depolarisations (PIDs) have on the brain in a stroke?

A

They worsen the damage int he penumbra - speeding past the core cells

50
Q

What is inflammation like after a stroke?

A

Not as high of an impact as the other symptoms but still affects cells

Can go on for days after

51
Q

How does inflammation after a stroke work?

A

It is the body’s immune system attempting to repair –> sends cells such as WBCs to the ares

HOWEVER –> prolonged inflammatory response = harmful

Cytokines can be released in this process & if too many released = damage healthy tissue around stroke site

52
Q

When does apoptosis occur during a stroke & what effect does it have?

A

After all the other types of damage, cell death occurs last

Programmed cell death, particularly in the penumbra

53
Q

What happens in a cell when there is a stroke?

(This is a long process & may need to refer to diagram)

A
  • Blood flow blocked = cell deprived of O2 & glucose (energy failure)
  • Depolarisation = influx of Na+ & Ca2+ into cell & K+ out
  • Stressed cell releases excessive glutamate & builds up outside cell –> spreads to other cells & causes depolarisation
  • Cell swells
  • Ca2+ influx activates enzymes that damage cellular structures –> creates free radicals, these are unstable & cause more damage
  • Causes membrane to weaken & DNA damage means this can’t repair
  • Damaged cell starts inflammatory response –> this activates microglia & causes leukocyte infiltration
  • Cell death = cell death pathways activated (either apoptosis or necrosis)
54
Q

What is inflammation like in the brain after a stroke?

A
  • Neuronal damage = cells are depolarising = glutamate toxicity = cytokines activated
  • These cytokines activate microglia (immune cells of the brain) –> microglia release their own cytokines (positive feedback loop)
  • BBB is damaged –> means leukocytes that can’t normally enter now can (they also contribute more damage)
55
Q

What is vascular cognitive impairment (VCI)?

A

An umbrella term for many cognitive disorders thought to share vascular origin

56
Q

The same vascular risk factors that predispose someone to a stroke also inc the risk of what?

A

Developing dementia

57
Q

What neurodegenerative disease is sometimes classified as a vascular cognitive impairment?

& why?

A

Alzheimer’s

As many as 50% of brains w classic AZ pathology show evidence of cerebrovascular disease

58
Q

What are the main pathologies seen in cerebrovascular disease (VCI)?

A
  • Cerebral amyloid angiopathy
  • White matter change
  • Large vessel occlusion
  • Atrophy (loss of volume)
  • Lobar & deep haemorrhage
  • Infarcts
  • Enlarged perivascular spaces
  • Microbleeds
59
Q

What are cerebral amyloid angiopathys?

A

Beta amyloid plaques –> these accumulate in the brain

Condition where these accumulate around blood vessels in VCI diseases –> leads to blood flow problems

60
Q

What are the changes seen in white matter in VCI diseases?

A
  • Small lesions
  • Loss of volume
  • Disruption of myelin
61
Q

What are lobar & deep haemorrhages in VCI?

A
  • Lobare occur in lobes of brain
  • Deep occur in the deep structures of the brain
62
Q

What are infarcts in VCI?

A

Refer to areas of dead tissue in the brain caused by lack of blood flow

If not recovered quickly - cells here will die

63
Q

What are enlarged perivascular spaces in VCI?

A

Perivascular spaces = Fluid filled cavities that surround small blood vessels in brain

Enlarged = fluid fills up outside blood vessels

64
Q
A