Cerebrovascular Disease Flashcards by Leah Ritter

What are the deficits when the Anterior Cerebral Artery is affected?

upper motor neuron weakness
cortical sensory loss
contralateral hemiplegia (most often the leg)
“alien hand” syndrome (involuntary mvmts)

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What is the major deficit when the Posterior Cerebral Artery is affected?

contralateral homonymous hemianopia

ex: lesion on the right causes loss of left vision field in both eyes

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What are the major deficits when the Middle Cerebral Artery is affected (most common area of ischemia and infarcts)?

aphasia
contralateral face/arm/leg sensorimotor loss
gaze preference toward side of lesion

Lacunes: small, deep infarcts involving penetrating branches of MCA

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What is a thrombosis versus an embolism?

Thrombosis: clotting of blood within a vessel

Embolism: plug; detached thrombus occluding a vessel

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What is a “stroke” versus an “infarction”?

“stroke” is the clinical designation of symptoms

“infarction” is the actual lesion of brain parenchyma

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What are the most common cerebrovascular disorders?

global ischemia (ex: d/t shock)
embolism
hypertensive intraparenchymal hemorrhage
ruptured aneurysm

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Which is more limiting to the brain - lack of oxygen or lack of metabolic substrate?

lack of oxygen, since brain is highly aerobic

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What are some causes of focal ischemia?

embolic/thrombotic arterial occlusion

- ATHEROSCLEROSIS in HTN

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What type of area in the brain is most susceptible to ischemia and infarction?

-watershed regions

–damage is a SICKLE-SHAPED BAND OF NECROSIS over the cerebral convexity, a few cms lateral to the interhemispheric fissure

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What causes watershed infarcts?

occlusion of internal carotid artery

- hypotension in patient w/ carotid stenosis

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What are the symptoms of an ACA-MCA watershed infarct?

proximal arm and leg weakness

- transcortical aphasia (language issues)

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What is the main symptom of an MCA-PCA watershed infarct?

deficits in higher-order visual processing

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What is a common cause of internal carotid artery stenosis and where does it typically occur?

atherosclerosis
just beyond the carotid bifurcation

-thrombi are also common at the origin of the MCA and at either end of the basilar artery

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What do you hear on physical exam of a patient with carotid artery stenosis?

a carotid bruit that continues into diastole

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What is a consequence of thrombi that form in the internal carotid artery d/t stenosis?

thrombi can embolize distally
-especially to MCA, ACA, and ophthalmic artery

Symptoms:

CONTRALATERAL FACE/ARM WEAKNESS
contralateral sensory changes
CONTRALATERAL VISUAL FIELD DEFECTS
APHASIA

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What are possible treatments of carotid stenosis?

angioplasty
stenting
endarterectomy (longitudinal cut to remove plaque)

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What is an atheroma?

an intimal lesion that has a lipid core covered by a fibrous cap

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What is the mechanism behind how atherosclerotic plaques cause thrombi?

-rupture, ulceration, or erosion of the plaque exposes blood to thrombogenic substances that lead to thrombosis and clots

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True or False: thrombotic occlusions occur mostly d/t atherosclerosis

True

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What is the shape of an infarct d/t a thrombus?

wedge-shaped

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What are causes of cardioembolic infarcts?

afib
MI (hypokinetic or akinetic areas)
valvular dz (thrombi on diseased/prosthetic leaflet)
dissection (carotid or vertebral aa.)
PFO (paradoxical embolus; DVT becomes a stroke)

What are sources of emboli?

air emboli (deep sea divers, iatrogenic)
septic emboli (bacterial endocarditis)
marantic emboli (proteinaceous)
-d/t non-bacterial thrombotic endocarditis
amniotic fluid emboli (childbirth)
fat/cholesterol emboli (long bone trauma)
-especially if you see megakaryocytes
-“shower emboli”

What artery in the brain is most affected by embolic infarction?

MCA

–usually in areas where blood vessels branch or in pre-existing areas of luminal stenosis

What are possible hypercoagulable states that can lead to neurologic effects?

coagulation factor disorders (Protein C, or Protein S)
dehydration
adenocarcinoma (or other malignancies)
surgery, trauma, childbirth
DIC
sickle cell, leukemia, polycythemia
vasculitis (temporal arteritis, SLE)

What is a TIA (Transient Ischemic Attack)?

- neurological deficit lasting <24hrs caused by temporary brain ischemia (usually 10 mins) - deficits longer than 10 mins probably produce some level of permanent cell death

True or False: TIA's are a warning sign of a potentially larger ischemic injury to the brain

True; it is a neurologic emergency since 15% of TIA pts will have a stroke that causes persistent deficits within 3 months (50% of those will occur within the next 48hrs)

What are common causes of a TIA?

- embolus that temporarily occludes, but dissolves - in situ thrombus formation - vasospasm

What are the two types of stroke?

Hemorrhagic (Red, d/t emboli) - intracerebral or subarachnoid hemorrhage - can cause hemorrhage secondary to reperfusion Ischemic (White, d/t thrombus) -can have a hemorrhagic conversion d/t fragile vessels rupturing, leading to a secondary hemorrhage

What are lacunar infarcts?

- infarctions of the deep penetrating arteries that develop arteriolar sclerosis (lenticulostriate aa.) - single or multiple small cavitary localized infarcts

What symptoms are associated with infarction of the lenticulostriate aa.?

- pure motor hemiparesis (d/t the posterior limb of the internal capsule) - thalamic lacune causes contralateral somatosensory defecits - basal ganglia lacune causes hemiballismus

What are slit hemorrhages?

--affect small caliber penetrating vessels to create slit-like cavities --slit is surrounded by pigment-laden macrophages --gliosis present

What is hypertensive encephalopathy?

-occurs with BPs of 200/130

What HTN risk factor is most commonly associated with deep brain parenchymal hemorrhages?

hypertensive encephalopathy | -potentially d/t malignant HTN

What is Binswanger Disease?

-large area of subcortical white matter w/ myelin and axon loss

What are Charcot-Bouchard Microaneurysms?

-minute (<300 micrometers) aneurysms in the basal ganglia, associated w/ chronic HTN

What is Cerebral Amyloid Angiopathy?

- causes lobar hemorrhage | - involves the same AB amyloid as Alzheimer Dz deposited in vessel walls producing microbleeds

What is CADASIL (Cerebral Autosomal Dominant Ateriopathy w/ Subcortical Infarcts and Leukoencephalopathy)?

- recurrent strokes and dementia - first symptomatic around age 35 - thick media and adventitia, loss of smooth muscle - basophilic PAS+ deposits - NOTCH3 gene - -preferentially expressed in vascular smooth muscle

What are risk factors for a stroke?

- HTN - DM - hypercholesterolemia - cigarette smoking - family Hx - cardiac dz (valvular dz, afib, PFO, low EF) - hypercoagulability

What is an aneursym?

-localized abnormal dilation of a blood vessel (or the heart)

What is the most frequent cause of clinically significant subarachnoid hemorrhage?

rupture of berry aneurysm | usually in the Circle of Willis, so it begins as a basilar SAH

What is the most common site of a berry aneurysm in the Circle of Willis?

at the junction of the anterior cerebral artery and the anterior communicating artery

What type of aneurysm is most likely to be found at the basilar artery?

atherosclerotic (fusiform)

True or False: aneurysms are present at birth

False; they develop over time d/t underlying defect in the media of the vessel

What is a Giant Aneurysm?

- can involve more than one artery | - over 2.5 cm wide

What is a Mycotic Aneurysm?

- caused by an infected artery wall - rare - Mucor, Candida, Aspergillis

What is the demographic for ruptured berry aneurysms?

--females in their 40's --one-third of ruptures are associated with increased intracranial pressure (straining at stool, orgasms)

What is the iconic phrase used to describe the pain of a ruptured aneurysm?

"worst headache I've ever had"

What percentage of people die with the first ruptured aneurysm?

20-50%; repeat bleeding in survivors is common | 50% of aneurysms >10 mm bleed per year

What is a potential complication of a subarachnoid hemorrhage within the first few days, regardless of etiology?

-increased risk of ischemic injury d/t vasospasm, because the vessels are bathed in extravasated blood (especially likely if it involved the base of the brain and Circle of Willis)

What is an AVM (arteriovenous malformation) and their common locations in the brain?

- where an artery meets a vein w/o intervening capillaries - tangle, wormlike vascular channels w/ prominent pulsatile shunting and high blood flow - AVM can be located in the subarachnoid space, may extend into the brain parenchyma, or may be exclusively in parenchyma

What arteries in the brain most commonly have AVM's and what is the age demographic when they most commonly cause bleeds?

MCA and posterior branches 10-30 yrs old