Chapter 446 Cerebrovascular Disease

Question 1

What is a Stroke or Cerebrovascular accident?

Answer 1

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

Neuro signs & symptoms last for >24h

Brain infarction is demonstrated

Question 2

Why do neurologic symptoms manifest within seconds

Answer 2

Because neurons lack GLYCOGEN, so energy failure is rapid

Question 3

TIA (Transient Ischemic Attack)

Answer 3

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

Question 4

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

Answer 4

Hypoxic-ischemic encephalopathy

Question 5

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

Answer 5

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

Question 6

How does INTRACRANIAL HEMORRHAGE produce neuro symptoms? (3)

Answer 6

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

Question 7

Loss of the appreciation that something is wrong

Answer 7

Anosognosia

Question 8

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

Answer 8

Seizure
Intracranial tumor
Migraine
Metabolic encephalopathy

Question 9

Migraine without head pain (term)

Answer 9

Acephalgic Migraine

Question 10

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

Answer 10

CT imaging of the brain

Question 11

Cerebral blood flow = 0

How long before death of brain tissue occurs?

Answer 11

Within 4-10 minutes

Question 12

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

How long before infarction occurs?

Answer 12

Within an hour

Question 13

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

Answer 13

<20 ml/100g tissue/minute

Question 14

Ischemic penumbra

Define.

Answer 14

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

Question 15

Goal of revascularization therapies.

Answer 15

Saving the ischemic penumbra.

Question 16

Focal cerebral infarction 2 distinct pathways.

Answer 16

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

Question 17

How does ischemia produce necrosis?

Answer 17

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

Question 18

How does excess extracellular glutamate produce neurotoxicity?

Answer 18

by activating postsynaptic glutamate receptors that increase neuronal calcium influx

Question 19

How are free radicals produced?

Answer 19

Degradation of membrane lipids and mitochondrial dysfunction.

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

Question 20

First goal in the treatment of acute stroke

Answer 20

Prevent or reverse brain injury

Question 21

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

Answer 21

Deficit that is maximal at onset or remits

Question 22

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

Answer 22

More depressed level of consciousness

Higher initial BP

Worsening of symptoms after onset

Question 23

Immediate goal in ischemic stroke

Answer 23

Optimize cerebral perfusion in the surrounding ischemic penumbra

Question 24

When SHOULD blood pressure be lowered?

Answer 24

Malignant hypertension

Concomitant myocardial ischemia

BP >185/110mmHg and thrombolytic therapy is anticipated

Question 25

Cerebral edema peaks on the _____ day Can cause mass effect for ___ days?

Answer 25

Peaks on the 2nd or 3rd day Can cause mass effect for 10 days

Question 26

IV rtPA dose and how is it administered

Answer 26

IV rtPA 0.9mg/kg (90mg MAXimum) | 10% as bolus, the remainder over 60mins

Question 27

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

Answer 27

NINDS rtPA Stroke Study | National institute of Neurological disorders and stroke

Question 28

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

Answer 28

ECASS III | European cooperative acute stroke study III

Question 29

Define. "Time of stroke onset"

Answer 29

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

Question 30

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

Answer 30

- 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

Question 31

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

Answer 31

- 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

Question 32

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

Answer 32

PROACT II trial Prolyse in Acute Cerebral Thromboembolism

Question 33

Trial. Endovascular thrombectomy device restored patency within 8h

Answer 33

MERCI & multi-MERCI trials Mechanical embolus removal in cerebral ischemia

Question 34

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

Answer 34

Penumbra pivotal stroke trial

Question 35

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

Answer 35

Interventional Management of Stroke III trial

Question 36

Trial. IV rtPA vs IA rtPA, within 3h, Italy

Answer 36

SYNTHESIS trial.

Question 37

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

Answer 37

IST trial International Stroke Trial

Question 38

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

Answer 38

CAST Chinese Acute Stroke Trial

Question 39

Trial. An investigational LMWH failed to show any benefit over aspirin.

Answer 39

TOAST The US trial of Organon 10172 in acute stroke treatment

Question 40

Cardioembolism is responsible for __% of all ischemic strokes

Answer 40

20%

Question 41

Emboli from the heart most often lodge in the? | 4

Answer 41

Intracranial internal carotid artery MCA PCA ACA (infrequently)

Question 42

Most common cause of cerebral embolism overall.

Answer 42

Nonrheumatic AF