Vascular Neurology Flashcards
transient ischemic attack (TIA)
defined as a transient episode (<24 hours) of neurologic dysfunction caused by focal ischemia, without acute infarction
ABCD2 score
used to predict 7 day risk for stroke after TIA
Age, Blood pressure, Clinical features, Duration of TIA, Diabetes
No points: Age <60, BP <140/90, Clinically no speech deficit or unilateral weakness, duration <10 mins, no diabetes
1 point: Age >/=60, BP >/= 140/90, speech deficit without unilateral weakness, duration 10-59 mins, + diabetes
2 points: unilateral weakness, >/= 60mins
7 day risk of stroke based on ABCD2 score`
0-3 points: 1.2%
4-5 points: 5.9%
6-7 points: 11.7%
what does ABCD2 score not include
does not take into account severe carotid or intracranial stenosis which is also a risk for ischemic stroke after TIA
ischemic stroke subtypes
large-artery atherosclerosis
cardioembolism
lipohyalinosis/small-vessel disease
stroke of other undetermined etiology
stroke of undetermined etiology
large-artery atherosclerosis
most common cause of ischemic stroke in the world
patients will either have significant stenosis or occlusion of a major brain artery or branch cortical artery
symptomatic carotid
stenosis of the common carotid ipsilateral to a TIA or infarct
treatment for symptomatic carotid
carotid endarterectomy (CEA) or carotid artery stent (CAS) is indicated if the stenosis is 50-99% in men or 70-99% in women
asymptomatic carotid stenosis should be treated surgically if the stenosis is 80-99%
CEA has a higher risk of periprocedural myocardial infarction
CAS has a higher risk of periprocedural stroke
treatment with CEA or CAS can lead to cerebral hyperfusion syndrome
cerebral hyperfusion syndrome
presents with headaches, visual disturbances, and seizures
occurs secondary to dysautoregulation of cerebral vessels in regions which have been in chronic low flow states
cardioembolism
most common cause of ischemic stroke in the US
patients can present similarly with comparable imaging to those with large artery atherosclerosis but will have a cardiac source for the embolic phenomenon
sources of cardioembolism
atrial fibrillation, mechanical heart prosthetic valve, left atrial or ventricular thrombus, recent myocardial infarction, dilated cardiomyopathy, valvular heart disease, structural heart defects, tumors
CHA2DS2-VASc score
helps to calculate risk of stroke in patients with untreated atrial fibrillation
CHF, Hypertension, Age (>/=75), Diabetes, Stroke or TIA history, Vascular disease, Age (65-74), Sex category
CHA2DS2-VASc scoring
0 points: no CHF, BP </= 140/90, no diabetes, no history of stroke or TIA, no vascular disease, age <65, male
1 point: yes CHF, BP >140/90, yes diabetes, yes vascular disease, age 65-74, female
2 points: age >/= 75, yes stroke or TIA history
lipohyalinosis/small-vessel disease
commonly occurs in the lenticulostriate vessels of deep cortical structure
also known as lacunar strokes that are felt to be related to chronic hypertension, diabetes, and smoking
hypercoagulable states and coagulopathy
examples: Factor V Leiden, antiphospholipid antibody syndrome, protein S/C deficiency, prothrombin gene mutation, antithrombin III syndrome, sickle cell disease, thrombotic thrombocytopenic purpura (TTP), polycythemia, hyperhomocysteinemia, MTHFR gene mutations, and malignancy
more likely to cause venous events than arterial
cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)
autosomal dominant disease due to a mutation of the NOTCH3 gene on chromosome 19 leading to a vasculopathy affecting the small to medium-sized arteries of white matter
cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) presentation
patient will present with recurrent stroke, headaches, seizures, and cognitive defects
cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) pathology
granular osmiophilic material (GOM) in the basal lamina of small cutaneous arterioles on electron microscopy or will be PAS-positive and congo-red negative on staining
cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) imaging
scattered bihemispheric T2 FLAIR hyperintense lesions
CNS Vasculitis
caused by a diverse spectrum of diseases that typically involves the gray/white matter junction
CNS Vasculitis DWI
multiple small focal areas of acute infarction in multiple vascular territories
CNS vasculitis vessel imaging
marked beading and segmentation alongside numerous arterial structures
primary angiitis of the CNS (PACNS)
vasculitis confined only to the small-medium sized blood vessels in the brain, spinal cord, and meninges
moyamoya disease
congenital moyamoya disease is seen most often in patients of Asian descent
Mysterin/RNF213 is a susceptibility gene for congenital moyamoya
secondary causes of moyamoya
head/neck radiation, sickle cell disease, neurofibromatosis, and prothrombotic disorders
moyamoya on angiogram
abnormal vascular pattern of small net-like lenticulostriate vessels characterized as a “puff of smoke” with severe stenosis or occlusion of the distal internal carotid arteries
moyamoya pathology
large vessel thickening of the intima, small overgrown dilated small arteries, and regions of ischemic and/or hemorrhagic infarct
arterial dissection
due to a tear of the vessel wall intima leading to a formation of a false lumen
arterial dissection symptoms
head/neck pain and Horner syndrome
ischemic events occur due to thromboemboli formation and less often cerebral hypoperfusion
arterial dissection common
common cause of stroke in the young
should be considered in a patient with a history of neck trauma chiropractic neck manipulation/high-velocity neck injury, or connective tissue disease (fibromuscular dysplasia, Marfan syndrome, Ehlers-Danlos)
arterial dissection on imaging
often extracranial and vessel imaging may show a “string sign” or flame-shaped occlusion in the are of dissection
patent foramen ovale (PFO)
seen in roughly 20% of people and its presence alone is not a strong risk factor for ischemic stroke. PFOs shouldn’t be considered as an etiology for stroke unless a patient presents with a cryptogenic embolic stroke
- lesions that are large, have a significant right to left shunt or are accompanied by an atrial septal aneurysm have a higher risk of recurrent stroke
PFO standard of care for secondary stroke prevention
antiplatelet therapy
recent data suggests that surgical PFO closure for those with high-risk features reduces the risk of recurrent stroke, and should be considered if patient is <60 years of age
PFO closure in young stroke patients decreases the risk of secondary stroke
air embolus
entry of air into the vasculature can be related to surgery, trauma, intravascular catheters, and barotrauma
if CTH performed promptly after insult, air can be seen within the cerebral vessels
treatment includes emergent use of hyperbaric oxygen chamber, but the prognosis is often poor
fat embolism syndrome (FES)
occurs secondary to long bone or pelvic fractures leading to the release of fatty bone marrow into the systemic circulation
emboli obstruct pulmonary arteries leading to respiratory distress
microemboli can pass through the pulmonary circulatory system and extend into the systemic arterial system and brain leading to small, randomly distributed ischemic strokes
hypoperfusion
can cause watershed regions between major vascular territories to become ischemic
hypoperfusion on imaging
ischemia along border zone regions of the ACA-MCA and MCA-PCA territories
bilateral ACA-MCA border zone infarcts
man in the barrel syndrome: upper extremity paralysis with retained strength in lower extremities
bilateral MCA-PCA border zone infarcts
Balint’s syndrome: simultagnosia, oculomotor apraxia, and optic ataxia
mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS)
mitochondrial disease caused by a mitochondrial DNA mutation to the gene MT-TL1
MELAS symptoms
ischemic strokes, seizures, and headaches present before the age 40
MELAS testing
reveals elevated CSF lactate levels, serum lacic acidosis, and ragged red fibers on muscle biopsy
drugs/toxins that cause stroke
cocaine and amphetamines
stroke of undetermined etiology
diagnosis that is given to patients in which a cause of stroke cannot be determined with any degree of confidence
many patients with stroke of undetermined etiology will ultimately be found to have paroxysmal atrial fibrillation with prolonged heart monitoring
stroke risk factors
hypertension is the most important risk factor
others include diabetes, smoking, and hyperlipidemia
pathology of ischemic stroke
brain ischemia leads to excessive extracellular glutamate. this leads to hyperexcitation of neurons and activation of an apoptotic cascade that leads to cell death
gross pathology of stroke
acutely: swelling with effacement of the gray-white junction and cracking at the interface between the intact and infarcted brain tissue
over time: infarcted tissue becomes sharply demarcated and is eventually replaced by a cavity
micropathology of stroke
initially no changes on H&E stain for the first 8 hours
in the following days, hypereosinophilic anoxic neurons, also known as red dead neurons, develop
in the following weeks, the lesion undergoes liquefaction as macrophages enter the space and ingest necrotic tissue
thereafter, astrocytes will form a glial scar around the infarct. this is completed in the proceeding months after an ischemic insult
acute treatment of stroke
tissue plasminogen activator (tPA)
tenecteplase (TNK)
tissue plasminogen activator (tPA)
works by transforming plasminogen into plasmin, leading to fibrinolysis of clot
can be given within 4.5hrs from the time of last seen well
tenecteplase (TNK)
modified form of human tPA
EXTEND-IA TNK study showed that TNK was associated with a higher rate of reperfusion and better functional outcome than alteplase in patients with large vessel occlusions (LVO)
many institutions are transitioning from alteplase to TNK for acute IV thrombolytic therapy in patients with acute ischemic stroke
when to start aspirin and DVT prophylaxis after IV thrombolytics
24 hours as long as CT head shows no hemorrhagic conversion of an ischemic stroke
absolute IV thrombolytic exclusion criteria
ischemic stroke or severe head trauma in the previous three months
previous intracranial hemorrhage
history of intracranial neoplasm
GI malignancy or hemorrhage in the previous 21 days
intracranial or intraspinal surgery within the previous 3 months
subarachnoid hemorrhage
blood pressure >/=185 systolic or >/=110 diastolic
active internal bleeding
aortic arch dissection
acute bleeding diathesis, including but not limited to conditions defined as “hematologic”
platelet count <100,000/mm
current anticoagulant use with an INR >1.7, PT >15 secs, or aPTT >40secs
LMWH use within 24 hours for PE or DVT (not at prophylactic doses)
direct thrombin inhibitor, direct factor Xa inhibitor, or glycoprotein IIb/IIIa receptor inhibitor use
evidence of hemorrhage on CT head
extensive regions of hypodensity consistent with irreversible ischemic injury
relative IV thrombolytic exclusion criteria
minor rapidly improving symptoms
serum glucose <50mg/dL
serious trauma or major surgery in the previous 14 days
history of GI bleeding or GU bleeding
seizure at stroke onset
pregnancy
arterial puncture at a noncompressible site in the previous 7 days
large (>/=10mm), untreated, unruptured intracranial aneurysm
intracranial vascular malformation
intra-arterial therapy (IAT)
while initial trials (REVASCAT, SWIFT PRIME, EXTEND-IA, and ESCAPE) showed a benefit from mechanical thrombectomy in the first 6 hours of last seen well, more recent trials (DAWN and DEFUSE 3) have shown benefit up to 24 hours from last seen well in select patients
- patients who undergo IAT should have a LVO seen on CTA/MRA
IAT of unclear or prolonged last known well
should have CT perfusion or MRI perfusion scan to identify the area that has already infarcted (the “core”) and the are that is at risk of infarction but is not yet dead (the “penumbra”)
- good candidates for IAT have a small or no core and a significantly larger penumbra
on CT perfusion:
- low cerebral blood volume (CBV) and high mean transit time (MTT) suggests dead (core) tissue
- normal or high blood volume and high mean transit time (MTT) suggests at-risk tissue (penumbra)