(27A) Ischemic Stroke Flashcards Preview

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Flashcards in (27A) Ischemic Stroke Deck (27):
1

Difference between stroke, TIA, and RIND

stroke = abrupt onset of focal neurologic deficits that may be irreversible (leads to permanent deficits)

TIA = abrupt onset of focal neurologic deficits that resolve in < 1 hr and the deficits may be reversible (usually? don't show changes on MRI)

RIND = abrupt onset of focal neurologic deficits that take LONGER THAN 1 HR to resolve + MRI that shows evidence of focal brain damage

2

Hemorrhagic or ischemic stroke more common?

ischemic (83% vs 17%)

3

4 main causes of ischemic strokes

1. artherosclerotic occlusion
2. embolism
3. Lacunae (dz that occludes small arterioles)
4. Cryptogenic (= unknown)

4

modifiable risk factors for stroke

male, > 55, african american, FH

5

Modifiable risk factors for stroke

SHODDY + Afib + carotid artery stenosis
smoking
HTN
obesity
DM
DYslipidemia

**HTN is the # 1 RF but afib has the highest relative risk

6

What accelerates and worsens stroke brain injury? Why

hyperthermia and hyperglycemia

ischemic neurons undergo glycolysis/anaerobic respiration which causes a build-up of lactic acid, which damages neurons when it builds up

inc temp speeds up the glycolytic process and hyperglycemia increases the substrate for the accumulation of lactic acid

7

clinically relevant aspect that differentiates ischemic core tissue vs penumbra

core suffers irreversible injury in <1 hr and pemubra ~4-6 hrs

8

CBF =

CBF = MAP / CVR

9

CBF will not change between MAP of ____ and ____. Significance?

55 - 150 mmHg; CBF will not change with changes in body position

10

How does HTN affect CBF autoregulation? Clinical significance?

shifts curve to the RT = MAP plateau has a higher set point

significange = they will have dec CBF at 75 mmHg (instead of 50) therefore you must be careful not to acutely lower BP too low (into levels that would be normal for a healthy indiv)

11

MAP above 150 mmHg leads to a condition known as

hypertensive enchephalopathy

12

What CBF is the threshold for infarction? normal CBF?

20 ml/100g/min vs 55ml/100g/min

13

anterior circulation strokes invovle what arteries

ACA, MCA, ICA and any of their branches

14

small penetrating branches of MCA that go into the putamen and globus pallitus

lenticulostriate arteries

15

presentation of ACA stroke

contralateral motor and sensory deficits in lower limb + frontal lobe behavior abnormalities

16

presentation of superior branch MCA stroke

contralateral motor and sensory deficits in upper limb and face + Broca's (non-fluent) aphasia

17

presentation of inferior branch MCA stroke

Wernicke's (fluent) aphasia if in dominant hemisphere and hemineglect if in non-dominant

absent motor findings

18

presentation of stroke in lenticulostriate arteries

contralateral motor hemiparesjs

**common site of lacuna infarct secondary to unmanaged HTN

19

presentation of stroke in PCA

contralateral homologous hemianopia (macular sparing)

larger infarcts with thalamus and internal capsule involvement my cause contrlateral hemisensory loss and hemiparalysis

20

What are the common sites of atherlosclerotic plaques

origins of carotid and vertebral arteries
bifrication of carotid
ICA at carotid siphon
ICA branch pts of ACA and MCA
M1 segment of MCA
Basilar Artery

21

pathogenesis/etiology of lacunar strokes

microartheroma (~artherothrombosis)
microemboli (from proximal vessels or heart--post MI, afib, valvular heart disease)
lipohyalinosis
fibrinoid necrosis (from chronic HTN)

22

What are the common causes of cardiogenic emboli

afib
valvular heart dz (mitral stenosis, bacterial endocarditis, prosthetic valves)
mural thrombosis post MI

**less common = atrial myxoma, mitral valve prolapse, non-bacterial endocarditis (cancer or lupus), paradoxal embolus (DVT that bypasses lungs through VSD or patent foramen ovale)

23

How is CNS vasculitis differentiated from other etiologies of ischemic stroke?

vasculitis is MULTIFOCAL -- see segmental narrowing with multiple occlusions

24

What types of vasculitis wil affect the vessels in the CNS?

lupus, giant cell arteritis, infectious vasculitis (syphillis, lyme, AIDS, zoster, hep B), Hypersensitivity vasculitis, wegener's, bechet's

25

what heme disorders can cause ischemic stroke?

hyperviscosity syndrome (multiple myeloma, polycythemia)
hypercoag state
sickle cell

26

What drugs are assc with ischemic strokes

cocaine, LSD, amphetamine, ETOH, OCPs

27

Cause of ischemic stroke secondary to trauma

carotid or vertebral artery dissection