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Flashcards in Ischemic Stroke Deck (42):
1

Stroke

-injury to brain caused by interruption of its blood flow (ischemic) or by bleeding (hemorrhagic) into or around the brain
-abrupt onset if focal neurologic deficits that frequently result in permanent disability or death

2

Transient Ischemic Attack

(TIA)
-abrupt onset of focal neurological deficits that resolve within less than 1 hr
-important warning sign for future stroke

3

Hemorrhagic Stroke

17%
-Intracerebral Hemorrhage: into parenchyme of brain
-Subarachnoid Hemorrhage: bleeding around surface of brain

4

Ischemic Stroke

83%
-atherosclerotic cerebrovascular disease (20%)
-embolism (20%)
-lacunar (25%)
-Cryptogenic (30%)

5

Non-Modifiable Stroke Risk Factors

-Age: doubles each decade > 55y
-Gender: male 1.5 x risk of female
-Race: AA 2 x risk of european americans
-Family History: genetics

6

Modifiable Stroke Risk Factors

-HTN (inc. 3-5)
-Diabetes
-Hyperlipidemia (2)
-Carotid Artery Stenosis (2)
-Atrial Fibrillation (5-17)
-Obesity (2)
-Physical Inactivity (2.7)
-Smoking (1.5)

7

Stroke Pathogenesis

-hyperthermia & hyperglycemia accelerate & worsen stroke brain injury
-with loss of blood supply, brain energy stores are depleted through metabolism of of glucose via glycolytic pathways with the accumulation of lactic acid (if not fixed cell dies by catabolic mechanisms)

8

Goal for stroke intervention?

-normalize elevated body temperature
-treat hyperglycemia

9

Stroke Pathogenesis by Section

-Core: severe ischemia, tissue dies <1hr
-Penumbra: moderate ischemia, tissue dies in ~4-6hr

10

Cerebral Blood Flow Autoregulation

-stays constant with mean arterial pressure from 55 to 155 mm Hg
-severe hypotension leads to reduced CBF & syncope
-elevation of MAP above 155mm HG cause hypertensive encephalopathy
-in chronic HTN curve shifts to right ( now 75mmHg)

11

CBF

measured in ml/100 gm brain/min is proportionally related to the mean arterial pressure (MAP) divided by the cerebral vascular resistance

12

Neurologic Deficits that are commonly produced by a stroke?

-weakness or paralysis
-loss of sensation
-loss of vision in one eye or field
-difficulty in talking or in understanding what is being said
-difficulty with organization or perception
-clumsiness or lack of balance

13

Anterior Circulation

-Internal Carotid, Middle Cerebral, Anterior Cerebral Arteries and any of their branches

14

Posterior Circulation

-Posterior cerebral, vertebral, superior cerebellar, anterior inferior cerebellar, posterior inferior cerebellar arteries and any of their branches

15

Size of Blood Vessel: Ischemic Stroke Subtypes

Large
Small (long & short penetrating branches of these arteries)

16

Functional Brain Areas Supplied by Middle Cerebral Artery

-larynx, tongue, lips, face, thumb, fingers, hand, arm, shoulder, trunk, hip
-frontal eye fields

17

Functional Brain Areas Supplied by the Anterior Cerebral Arteries

-Foot, leg, hip

18

Blood Supply to Midbrain

-Posterior cerebral artery
-Superior Cerebral Artery

19

Blood Supply to Mid-Pons

-Short circumferential branches of basilar artery

20

Blood Supply Caudal Pons

-Anterior Interior Cerebral artery

21

Blood Supply to Rostral Medulla

-post inf. cerebellar artery

22

Medullary Stroke Syndrome (Wallenberg)

-loss of pain & temp. from ipsilarteral side of face
(lesion to spinal trigeminal nucleus & tract)
-dysarthria & dysphagia (leasion to nucleus ambiguus)
-loss of pain & temp on contralateral side of body'
(lesion to spinothalamic tract)
-gait ataxia on the ipsilateral side of the body
(lesion to spinocerebellar tracts)

23

Pontine Stroke Syndrome

-gaze disorders due to a lesion to the medial longitudinal lasciculus (CN VI)
-loss of discriminative touch, vibration & conscious proprioception on the contralateral side of the body due to a lesion of the medial lemniscus
-cerebellar lesions on both sides of the body due to lesion to the pontine nuclei & transverse cerebellar fibers originating from both the ipsilateral & contralateral sides
-contralateral hemiparesis due to lesion of the corticospinal tract

24

Midbrain Stroke Syndrome (Benedikt Syndrome)

-ipsilateral CN III palsy & loss of pupillary constriction due to damage of the oculomotor nuclear complex including the parasympathetic Edinger-Westphal nucleus
-Loss of discriminative touch on the contralateral side of the body due to a lesion of the medial lemniscus
-Contralateral tremor & ataxia due to a lesion of the red nucleus

25

Symptoms of Anterior Circulation Stroke

-Ipsilateral blindness or contralateral inferior quadrantanopsia
-contralateral gaze paresis
-contralateral mono/hemiparesis and or mono/hemisensory deficit
-aphasia in the dominant hemisphere or neglect in the nondominant hemisphere

26

Symptoms of Posterior Circulation Stroke

-Unilateral, bilateral, or crossed (face/body) weakness or sensory deficits
-Contralateral homonymous hemianopsia or superior quadrantanopsia
-Vertigo, nausea/vomiting, gait ataxia, diplopia, dysphagia, Horner's syndrome
-altered consciousness & amnesia

27

Lacune

"small cave"

28

Lacunar Stroke

-smaller areas of ischemic necrosis caused by occlusion of small, penetrating arteries

29

Lacunar Syndromes

1. Pure hemiparesis
2. Pure hemisensory deficit
3. Ataxia hemiparesis
4. Dysarthria-Clumsy hand syndrome

30

Ischemic Stroke Differential Diagnosis

-Hemorrhagic Stroke
-Subdural hematoma
-Syncope/near syncope
-Radiculopathy
-Bell's Palsy
-Multiple Sclerosis
-Brain Tumor
-Migraine
-Seizure
-Hypo & Hyperglycemia
-Hypoxia

31

Ischemic Stroke Pathogenesis

-Atherothrombosis/Atheroemboli
-Lipohyalinosis & Fibrinoid Necrosis (Small vessels causing lacunar strokes)
-Cardiogenic Emboli
-Vasculitis
-Hematologic Disorders
-Drug related

32

Common sites of Atherothrombosis/Atheroemboli

-origins of carotid & vertebral arteries
-bifurcations of common carotid arteries
-internal carotid arteries at the carotid siphon & at branch points of middle & anterior cerebral arteries
-M1 segment of middle cerebral arteries
-Basilar artery

33

Lacunar Stroke Pathogeness

-microatheroma
-microemboli
-lipohyalinosis - transformation of smooth muscle &
-fibrinoid necrosis intima of cerebral vessels from chronic HTN

34

Common Causes of Cardiogenic Emboli

-arrhythmia (a fib)
-valvular heart disease (mitral stenosis, bacterial endocarditis, prosthetic heart valves)
-mural thrombus (myocardial infarction)

35

Cardiogenic Emboli (uncommon)

-atrial myxoma
-valvular heart disease (mitral valve prolapse, nonbacterial (marantic) endocarditis caused by cancer or systemic lupus erythematous (libman-sacks emboli))
-Mural Thrombus (cardiomyopathy)
-Paradoxical embolus (right-left shunt)

36

CNS Vasculitis

-inflammation of CNS vessels producing segmental narrowing & multifocal occlusions
-neurologic presentation is multifocal reflecting multiple small & medium-sized vessel occlusions
ex: hypersensitivity vasculitis, wegeners granulomatosis, Behcet's disease, Primary CNS vasculitis)

37

Collagen Vascular diseases

-Lupus (most common)

38

Giant Cell Arteritis

-in patients >55 yrs (responds well to steroid)

39

Infectious Vasculitis

-syphilis, lyme, AIDS, zoster, hypatitis B, bacterial, fungal, TB

40

Hematologic Disorders

-Hyperviscosity (polycythemia, multiple myeloma)
-Hypercoagulable (antiphospholipid syndromes, protein C & S deficiency, cancer, pregnancy, Leiden factor deficiency, thrombocytosis)
-Hemoglobinopathies (sickle cell)

41

Drug Related Stroke

-Street Drugs: cocain (crack), LSD, amphetamines, phencyclidine, methylphenidate, sympathomimetics
-Ethanol
-Oral Contraceptives: high dose estrogen is greater risk

42

Other Causes of Stroke

-fibromuscluscular dysplasia (abnormal proliferation of tissue within blood vessel & uncommon cause of stroke)
-Carotid or vertebral artery dissection
-Homocystinemia
-Emboli (fat, air, bone marrow)
-Vasospasm (subarachnoid hemorrhage)
-Migraine