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xxxxxIM CHRON > Chapter 446 Cerebrovascular Disease > Flashcards

Chapter 446 Cerebrovascular Disease Flashcards

1
Q

What is a Stroke or Cerebrovascular accident?

A

ABRUPT onset of a neuro deficit attributable to a FOCAL vascular cause

Neuro signs & symptoms last for >24h

Brain infarction is demonstrated

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2
Q

Why do neurologic symptoms manifest within seconds

A

Because neurons lack GLYCOGEN, so energy failure is rapid

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3
Q

TIA (Transient Ischemic Attack)

A

ALL neuro signs & symptoms resolve WITHIN 24h without evidence of brain infarction on brain imaging

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4
Q

The constellation of cognitive sequelae that ensues after widespread brain injury caused by global hypoxia-ischemia.

A

Hypoxic-ischemic encephalopathy

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5
Q

FOCAL ischemia or infarction is usually caused by? (2)

A
  1. Thrombosis of cerebral vessels themselves or 2. Emboli from a proximal arterial source or the heart.
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6
Q

How does INTRACRANIAL HEMORRHAGE produce neuro symptoms? (3)

A
  1. Mass effect on neural structures
  2. Toxic effects of blood itself
  3. Increasing intracranial pressure
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7
Q

Loss of the appreciation that something is wrong

A

Anosognosia

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8
Q

Other causes of sudden-onset neuro symptoms that may mimic stroke

A

Seizure
Intracranial tumor
Migraine
Metabolic encephalopathy

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9
Q

Migraine without head pain (term)

A

Acephalgic Migraine

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10
Q

Standard imaging modality to detect the presence or absence of intracranial hemorrhage

A

CT imaging of the brain

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11
Q

Cerebral blood flow = 0

How long before death of brain tissue occurs?

A

Within 4-10 minutes

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12
Q

Cerebral blood flow = <16-18 ml/100g tissue/minute

How long before infarction occurs?

A

Within an hour

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13
Q

Cerebral blood flow value that causes ischemia without infarction unless prolonged for several hours or days.

A

<20 ml/100g tissue/minute

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14
Q

Ischemic penumbra

Define.

A

The ischemic but reversibly dysfunctional tissue surrounding a core area of infarction.

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15
Q

Goal of revascularization therapies.

A

Saving the ischemic penumbra.

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16
Q

Focal cerebral infarction 2 distinct pathways.

A
  1. Necrotic pathway
    - cellular cytoskeletal breakdown is rapid due to energy failure of the cell
  2. Apoptotic pathway
    - cells become programmed to die
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17
Q

How does ischemia produce necrosis?

A

By starving neurons of glucose and oxygen, which in turn results in failure of mitochondria to produce ATP.

  • no ATP>membrane ion pumps stop functioning>neurons depolarize>rise of intracellular calcium
  • cellular depolarization>glutamate release from synaptic terminals
18
Q

How does excess extracellular glutamate produce neurotoxicity?

A

by activating postsynaptic glutamate receptors that increase neuronal calcium influx

19
Q

How are free radicals produced?

A

Degradation of membrane lipids and mitochondrial dysfunction.

Free radicals cause catalytic destruction of membranes and likely damage other vital functions of cells.

20
Q

First goal in the treatment of acute stroke

A

Prevent or reverse brain injury

21
Q

Clinical finding/s that favor a dx of ISCHEMIC type of stroke (1)

A

Deficit that is maximal at onset or remits

22
Q

Clinical finding/s that favor a dx of HEMORRHAGIC type of stroke (3)

A

More depressed level of consciousness

Higher initial BP

Worsening of symptoms after onset

23
Q

Immediate goal in ischemic stroke

A

Optimize cerebral perfusion in the surrounding ischemic penumbra

24
Q

When SHOULD blood pressure be lowered?

A

Malignant hypertension

Concomitant myocardial ischemia

BP >185/110mmHg and thrombolytic therapy is anticipated

25
Q

Cerebral edema peaks on the _____ day

Can cause mass effect for ___ days?

A

Peaks on the 2nd or 3rd day

Can cause mass effect for 10 days

26
Q

IV rtPA dose and how is it administered

A

IV rtPA 0.9mg/kg (90mg MAXimum)

10% as bolus, the remainder over 60mins

27
Q

This study showed a clear benefit for IV rtPA in selected patients with acute stroke

A

NINDS rtPA Stroke Study

National institute of Neurological disorders and stroke

28
Q

This study explored the safety and efficacy of rtPA in the 3- to 4.5-hr window

Excluded patients older than 80yo and diabetic patients

A

ECASS III

European cooperative acute stroke study III

29
Q

Define.

“Time of stroke onset”

A

The time the patient’s symptoms were witnessed to begin or the time the patient was last seen normal.

30
Q

Indications for administration of IV rtPA for acute ischemic stroke
(5)

A
  • clinical dx of stroke
  • onset of symptoms to time of drug administration less than or equal to 4.5h
  • CT scan showing no hemorrhage or edema of >1/3 of the MCA territory
  • age more than or equal to 18yo
  • consent by patient or surrogate
31
Q

Contraindications to administration of IV rtPA in achte ischemic stroke
(10)

A
  • sustained bp >185/110mmHg despite tx
  • plt <100,000, hct <25%, glucose <50 or >400mg/dL
  • use of heparin within 48h and prolonged PTT, or elevated INR
  • rapidly improving symptoms
  • prior stroke or head injury within 3months; prior intracranial hemorrhage
  • major surgery in preceding 14days
  • minor stroke symptoms
  • GI bleeding in preceding 21days
  • recent MI
  • coma/stupor
32
Q

Trial.

Benefit for intraarterial prourokinase in acute MCA occlusion up to the 6th hour

A

PROACT II trial

Prolyse in Acute Cerebral Thromboembolism

33
Q

Trial.

Endovascular thrombectomy device restored patency within 8h

A

MERCI & multi-MERCI trials

Mechanical embolus removal in cerebral ischemia

34
Q

Trial.

Tested another mechanical device that showed higher rates of recanalization compared to MERCI (two Stentriever devices-nondetachable stents)

A

Penumbra pivotal stroke trial

35
Q

Trial.

IV rtPA alone vs IV rtPA followed by IA rtPA, within 3h
No benefits.

A

Interventional Management of Stroke III trial

36
Q

Trial.

IV rtPA vs IA rtPA, within 3h, Italy

A

SYNTHESIS trial.

37
Q

Trial.

Use of Aspirin (300mg/d) x 14d, reduced both stroke recurrence risk and mortality minimally

A

IST trial

International Stroke Trial

38
Q

Trial.

Use of aspirin (160mg/d) up to 4 weeks, reduced both stroke recurrence risk and mortality minimally.

A

CAST

Chinese Acute Stroke Trial

39
Q

Trial.

An investigational LMWH failed to show any benefit over aspirin.

A

TOAST

The US trial of Organon 10172 in acute stroke treatment

40
Q

Cardioembolism is responsible for __% of all ischemic strokes

A

20%

41
Q

Emboli from the heart most often lodge in the?

4

A

Intracranial internal carotid artery
MCA
PCA
ACA (infrequently)

42
Q

Most common cause of cerebral embolism overall.

A

Nonrheumatic AF

xxxxxIM CHRON (7 decks)

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