CM: Aspects of Vascular Dz Flashcards
What are the two different kinds of strokes?
ischemic - artery occluded
hemorrhagic - artery ruptures
What is ACA territory often spared during ICA strokes?
because of communicating arteries
What main symptoms are seen in left MCA stroke vs. right?
left - aphasia
right - apraxia and/or sensory neglect
What do the deep branches of the MCA supply and what are symptoms of a stroke there?
basal ganglia, capsules, thalamus
contralateral hemiplagia of face, arm, and leg, sometimes with hemianesthesia
What structures are possibly affected by an ACA stroke?
medial portions of frontal and parietal, corpus callosum, sometimes caudate and internal capsule
What are the symptoms of an ACA stroke?
contralateral hemiplagia (esp leg - fibers more medial), grasp reflex, urinary incontinence bilateral occlusion may cause spastic paraparesis, emotional disturbances, apathy, confusion, mutism
What structures are possibly affected by a PCA stroke?
occipital, splenium of CC, thalamus, midbrain
What are some symptoms of PCA strokes and why are they variable?
vision loss, thalamic injury, Weber’s syndrome (contralateral weakness and CN III involvement - oculomotor paresis and dilated pupil)
because of collateral and fetal circulation
What are TIAs?
temporary interruption of blood flow –> transient neurological dysfunction (<24 hrs)
w/o acute infarction
1/2 will have stroke, lots w/i 48 hrs
What are the five ischemic stroke subtypes defined by the TOAST criterion?
large vessel dz - atherosclerosis, most common
small vessel dz - lacunar strokes, penetrating artery dz
cardiogenic embolism
stroke from other determined cause
stroke from undetermined cause
By what two mechanisms can plaques cause ischemic strokes in large vessel dz?
flow reduction from stenosis or occlusion (when diameter reduced by ~70%) - near bifurcations
artery to artery embolism from ulcerated, thrombogenic surfaces - nonstenotic plaques can create platelet plugs that thrombose or embolize
What are the symptoms of small vessel dz strokes?
pure motor or pure sensory strokes involving face, arm, and leg simultaneously
can be debilitating and tend to recur
injury around lateral ventricles & subcortical white
Why are cardiogenic emboli strokes so easy to prevent?
cardiac symptoms usually present first and antithrombotic therapies very effective
What are the three key elements in diagnosing stroke due to cardiogenic embolism?
abrupt onset, cortical neurologic deficit, potential cardiac source
What are some other causes of strokes in young people?
hypercoagulable state, cocaine, neurosyphilis in HIV+
What are the main risk factors for ischemic stroke?
HTN, age and gender (after 55), smoking, diabetes, elevated cholesterol
What are the most common causes of CNS hemorrhages leading to hemorrhagic stroke?
HTN, aneurysm, subdural hematomas, AV malformations, amyloid angiopathy
What are hypertensive bleeds?
ruptures of small penetrating arteries –> hematoma in subcortical, pons, cerebellum, typically 55-75, VERY high BP on presentation
puts at risk for both types of stroke
What diagnostic studies can be done for further evaluation of pts with a stroke?
bloodwork - serum glucose and electrolytes, renal function, CBC, PT, INR, PTT (further testing for inf, inflammation, hypercoagulability deferred unless strong suspicion)
Cardiac studies - ECG, Echo
imaging - CT, CTA, MRI, MRA
Angiography - determines etiology after diagnosed by other means, gold standard, can intervene
What is the ischemic penumbra?
around area of necrosis - hypoperfused, hypometabolic,electrically silent tissue that has marginally sufficient flow to keep neuron alive
goal of acute stroke management is to salvage it
What are options for acute stroke treatment?
recombinant TPA - stimulates clot breakdown, only if symptoms <4.5 hrs, NIHSS demonstrates deficit, CT does not show bleeding or non-stroke cause of symptoms, main risk = bleeding, control elevated BP after
aspirin 160-300mg w/i 48 hrs, LMWH
What are contraindications for TPA?
seizure at onset of stroke, recent surgery/stroke, extreme uncontrollable elevations of BP, coagulopathy
What are established therapies that reduce the risk of stroke?
antiplatelet agents (aspirin, clopidogrel) - longterm
warfarin - not for initial, use in A fib
dabigatran - thrombin inhibitor, for A fib
Carotid endarterectomy (CEA) & Carotid angioplasty and stenting (CAS)
What pts can benefit from CEA?
symptomatic pts w TIA or stroke w/i past 6 mos (best w/i 2 wks) who had ipsilateral carotid stenosis of >70%
stenosis of 50-69% depends on pt factors
When is CAS maybe a better alternative than CEA?
symptomatic pts at avg or low risk of complications and stenosis >70%, lesions difficult to assess surgically
