Stroke Flashcards

1
Q

Describe a stroke

A

A stroke occurs when there is ischemia (inadequate BF) to a part of the brain that results in the death of brain cells.

Synonyms: CVA (cerebral vascular accident, cerebral ischemia)

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2
Q

Strokes are the ___ leading cause of death in Canada

A

3rd

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3
Q

What % of cardiac output goes to the cerebral BF?

A

20%

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4
Q

How long after full neurological BF occlusion does cellular death occur?

A

after 5 minutes

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5
Q

Describe cerebral autoregulation

A

Changes in diameter of cerebral BVs in response to changes in BP so the brain BP stays constant.

CO would have to be reduced by a third to reduce cerebral BF due to cerebral autoregulation shunting BF to the brain.

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6
Q

Compensating function of the Circle of Willis

A

If a blockage stops BF in a connected artery, the change in BP causes blood to flow forward or backward in the circle of Willis to compensate

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7
Q

What is a vasovagal response?

A

When BP temporarily drops causing pallor and fainting due to overactivity of vagus nerve.

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8
Q

What gender experiences more strokes?

A

Men

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9
Q

What gender dies more frequently due to strokes?

A

Women

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10
Q

What races have a higher risk factor for strokes?

A

African Americans, African-Canadians

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11
Q

What is one modifiable risk factor specifically in women for strokes?

A

Oral contraceptives and HRT (hormone replacement theory - used in menopause to give estrogen)

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12
Q

3 Contributing factors to strokes

A
  1. Hypertension (risk for atherosclerosis, thrombotic stroke, aneurysms)
  2. Diabetes (macrovascular complications)
  3. CAD (pooling blood from atrial fib can cause clots)
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13
Q

Describe Thrombosis

A
  • more common
  • platelet clot aggregation that forms, stays, and can eventually block vessel
  • slower symptom onset
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14
Q

Describe embolism

A
  • clot that develops, travels, and causes blockage somewhere else in the body
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15
Q

Describe hemorrhage

A
  • breaking the vessel wall
  • often atherosclerotic rupture
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16
Q

2 Types of strokes and their %s

A
  1. Ischemic Strokes (85%)
  2. Hemorrhagic Strokes (15%) POORER PROGNOSIS
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17
Q

3 types of Ischemic strokes and which is more common

A
  1. TIA
  2. Thrombotic (more common)
  3. Embolic (less common)
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18
Q

2 types of hemorrhagic strokes and which is more common

A
  1. Intracerebral (more common)
  2. Subarachnoid (less common)
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19
Q

Explain how cerebral ischemia can come from thrombosis/embolism or HTN/aneurysm

A

Thrombosis/embolism -> cerebral infarction (loss of BS) -> less cerebral perfusion & increased intracranial pressure

HTN/Aneurysm -> cerebral hemorrhage -> less cerebral perfusion & increased intracranial pressure

20
Q

How long does a TIA last?

A

Often after 15 mins

21
Q

What causes a TIA?

A

microemboli

22
Q

Difference in symptoms between thrombotic and embolic strokes

A

Thrombotic: slow and progressive, may not have LOC change in first 24 hours

Embolic: sudden, no chance to develop collateral circulation

23
Q

Describe an intracerebral hemorrhagic stroke

A

bleeding occurs in the cerebrum
- HTN is a big risk factor
- occurs during activity
- sudden onset
- headache, NV, altered LOC, HTN

24
Q

Describe a subarachnoid hemorrhagic stroke

A

bleeding in-between the pia mater and arachnoid mater of the brain
- Intracranial bleeding into cerebrospinal fluid space
- rupture of cerebral aneurysm, trauma, or cocaine
- headache, NV, altered LOC, HTN

*silent killer

25
Q

What’s the chance of dying within 30 days after a hemorrhagic stroke?

A

40-80%, but over half die soon after the initial hemorrhage

26
Q

What’s the chance of dying during the first episode of a ruptured aneurysm?

A

40%

27
Q

What do clinical manifestations of strokes depend on?

A

location, not type of stroke

28
Q

Right-brain damage symptoms:

A
  • paralyzed L side
  • spatial deficits
  • minimize problems
  • quick performance
  • short attention span
  • impulsive
  • impaired time concepts
29
Q

Left-brain damage symptoms:

A
  • paralyzed R side
  • aphasias (speech) & math difficulties
  • impaired R & L discrimination
  • slow performance
  • aware of deficits (depression)
30
Q

Diagnostics for strokes

A

Primary diagnostic: CT scan
Cardiac function: Troponin and CKMB, ECG, chest x-ray, cardiac markers, echocardiogram
Clotting factors: CBC, WBC, hemoglobin, electrolytes, glucose, A1C, lipid profile, renal and hepatic studies

31
Q

What is a carotid endarterectomy?

A

Removes plaque surgically

32
Q

FAST stroke warning signs

A

F - facial droop
A - arm weakness
S - speech difficulty
T - time to call 911

additional signs: vision problems, severe headaches, dizziness

33
Q

How fast from the onset of stroke symptoms should assessment, diagnostic studies, and thrombolytic therapy occur?

A

3-4 minutes from onset

34
Q

3 things to assess in stroke patients

A

Glasgow coma scale
PERRLA (dilation and non-activity is caused by low O2 to the brain)
Vitals

35
Q

Why is N&V a symptom of a stroke?

A

Increased ICP in medulla oblongata causes N&V

36
Q

4 key interventions for acute ischemic stroke

A
  1. Airway: O2 therapy, artificial airway
  2. Baseline neurological assessment
  3. BP meds not recommended unless SBP > 220 or MAP > 130
  4. Fluid and electrolyte balance - restriction of 1.5-2L/day, no hypotonic fluids that pull fluid into tissue which increases cerebral edema
37
Q

Formula for cerebral perfusion

A

Cerebral perfusion = MAP - ICP

38
Q

Priority Nursing interventions for strokes

A

Restore and maintain BF to the brain:
- HOB elevated to 30 to reduce ICP
- monitor BP
- give mannitol IV as a diuretic to decrease cerebral edema
- never give a stroke pt anything PO unless swallowing is assessed

39
Q

Medication Tx for acute ischemic strokes

A
  • tPA (clot buster so there is a risk of bleeding, given within 4.5 hours of onset)
  • ASA
  • anticoagulant and antiplatelet after stabilization (could increase risk for hemorrhage)
40
Q

Medication Tx for hemorrhagic strokes

A
  • Nimodipine - relaxes BVs for more BF, calcium channel blocker
  • SBP should be normal to high but < 160
41
Q

Formula for MAP

A

[ SBP + (2xDBP) ] /3

42
Q

Describe MAP

A

Average arterial pressure throughout one cardiac cycle, systole, and diastole

43
Q

Describe Cushing’s Triad

A

3 primary signs that often indicate an increase in ICP
1. ↑ SBP
2. ↓ HR
3. ↓ RR

44
Q

Interventions to decrease ICP

A
  • providing O2: rest, reduced stimulation
  • postures promoting venous return
  • no bearing down (Valsalva maneuver)
  • medically induced coma
45
Q

Medications to decrease ICP

A

Mannitol - diuretic draws fluid out of tissue
Hypertonic saline - draws water out of tissue
Steroids
Anti-seizure meds given prophylactically
BP meds