Stroke - Guest Lecture Flashcards
a brain attack in which there is damage resulting from an alteration in cerebral blood flow
stroke
what are the 2 types of stroke and what are their %
- ischemic: loss of blood flow - 87%
- hemmorhagic: 10% intracerebral and 3% subarachnoid hemorrhages
causes no permanent damage visible on MRI and whose sx resolve 100%
transient cerebral ischemia (TIA)
relative lack of O2 in arterial blood generally leading to altered metabolism and if not reversed, leads to cell death
hypoxia
complete deprivation of O2 supply
anoxia
potentially reversible tissue dysfunction secondary to hypoxia (however it may also result from organic poison, severe hypoglycemia); is always pathological
ischemia
tissues are lacking something
ischemia
ischemia can result in necrosis in vulnerable brain regions (ie hippocampus) in as little as
2 minutes
irreversible tissue death that is the result of ischemia
infarction
brain tissue destined to die; all dead
ischaemic core
salvageable brain area; not all is dead, can potentially save this area
penumbra
what is the 5th leading cause of death in the US and is leading cause of long term disability
stroke
how often does someone die of stroke in US, accounting for 1/20 deaths
4 minutes
how many adults over 20 have had a stroke already and how much is this expected to increase by 2030
7.2 million
3.4 million
how many stroke occur in the US per year and how many are new strokes
800,000
610,000
how much do strokes cost the US/year
34 billion
what percent of strokes occur in people under 50
10%
build up of plaque in arteries
atherosclerosis (build up of fat, cholesterol)
a blood clot that breaks off and travels
embolism
what are sources of emboli
- carotid (artery to artery embolism)
- cardioembolic (atrial fib, vegetations, low EF/LV thrombus, paradoxical embolism (PFO), hypercoagutable state)
most common cause of clots in the heart and causes a rhythm problem; most common irregular heart rhythm problem
artial fibulation
clot build up in the heart; may be sterile thrombus or infectious
vegetations
most common ischemic stroke
lacunar infarcts
small infarcts that affect the deeper parts of the brain
lacunar infarcts
what structures do lacunar infarcts affect
basal ganglia, thalamus, white matter
what % of all strokes are lacunar
20%
occurs due to occlusion of deep penetrating branches of major cerebral arteries
lacunar infarcts
what are lacunar infarcts associated with
hypertension, DM
involves small arteries and arterioles
hypertensive small vessel disease
types/affected hypertensive small vessel disease
athersclerosis
arteriosclerosis
maroaneurysms
thickened eosinophilic walls (lipohyalinosis)
arteriosclerosis
order of sensitivity to hypoxic ischemic encephalopathy
cerebral cortex and striatum –> thalamus –> brainstem
what area will have decreased blood flow first in brain with clogged arteries
the area furthest away from clot
what type of metabolism is the brain
aerobic
the brain lacks significant energy reserves so it required a continuous supply of well ____ _blood
oxygenated
how much blood and O2 does the brain require and how much does the brain weigh
20% cardiac output
15% O2 consumption at rest
brain is 2% total body weight
what brain structures are vulnerable to damage based on their high energy demands and metabolism
- purkinje cells of cerebellum
- pyramidal cells of CA1 - sommer’s sector of hippocampus
- middle layers of cerebral cortex - laminar necrosis (3 and 5)
- brain stem nuclei in infants
what area of the brain (gray or white) is at the highest level of hypoxia/metabolic poison
gray matter
inflammation of blood vessel walls; causes arteries to squeeze down
vasculitis
what are the 3 layers of an arterial wall
endothelial intima
smooth muscle media
connective tissue adventitia
cause of vasculitis
unknown, often not infectious
what is vasciulitis divided into
- large vessel (aorta and its main branches)
- medium vessel (muscular arteries)
- small vessel (arterioles, capillaries, venules)
74 y/o pt presents with history of HTN, smoking and diabetes. he presents with L arm and leg weakness. MRI shoes lacunar stroke, what is likely cause
- atheroembolic
- carioembolic
- septic emboli
- small vessel ischemia
small vessel ischemia
risk factors for intraparenchymal hemorrhage
- hypertensive hemorrhage
- vascular malformations
- amyloid angiopathy
- hemorrhagic transformation of infarcts
- hemorrhagic tumors
- anticoagulation
locations of intraparenchymcal hypertensive hemorrhage
basal ganglia
thalamus
pons
cerebellum
cerebral hemispheres (lobar)
tangle of abnormal arteries interposed between a feeding artery and draining veins
arteriovenous malformation (AVM)
arteries most to least at risk for AVM
MCA > ACA > PCA
cluster of cavernous vessels without intervening stroma; just veins are involved
cerebral cavernous malformation
epilepsy or recurrent HA common signs; annual risk of bleeding is 1%; familial forms are common in those of Mexican-american heritage; autosomal dominant (CCM1-3 genes in chromosome 3 and 7)
cerebral cavernous malformation
may produce lobar hemorrhage; most cases are due to deposition of beta-amyloid (associated with AD) in leptomeningeal and cortical small arteries; proteins causing bleeding in the brain
cerebral amyloid angiopathy
brain tumors that are prone to hemorrhage
- gliomas (GBM/oligo)
- metastatic: melanoma, renal cell carcinoma, thyroid carcinoma, choriocarcinoma, lung CA
3rd most common cerebrovascular lesion (after cerebral infarction and hypertensive hemorrhage); rupture of a berry aneurysm is the most common cause
non-traumatic subarachnoid hemorrhage (SAH)
is the most frequent intracranial arterial aneuryrsm
berry aneurysm (aka saccular or congenital anneurysm)
where to aneurysms tend to occur most often
at vessel branch points in circle of willis
individuals with two first degree relatives who have _______ should be screened with cerebral vascular imaging
intracranial aneurysms
list s/s of stroke
vertigo, fatigue/depressed level of consciousness, dysarthria, aphasia, dysphagia, apraxia, agnosia, gaze preference, ataxia, neglect, disconjugate gaze
room spinning
vertigo
slurred speech
dysarthria
trouble producing speech, cannot say what they want, frustrated
expressive aphasia (Broca’s)
say words but don’t make any sense, cannot follow commands
receptive aphasia (wernickes)
difficulty swallowing
dysphagia
cannot perform purposeful movements; inability to use voluntary use of strength
apraxia
difficulty recognizing things
agnosia
with gaze preference, do the eyes look toward or away from the side of the stroke
toward
loss of coordination but limbs are still strong
ataxia
unable to acknowledge one side of the body, pt doesn’t realize they have a problem
anosognosia (neglect)
can acknowledge each side individually, but when on both sides simultaneously, they will not be able to see/feel impaired side
extinction (neglect)
how to test for disconjugate gaze and how to interpret
test by coverign one eye at a time for 30 seconds
- brain problem: blurry vision that goes away when pt covers 1 eye
- eye problem: blurry vision that stays blurry when cover 1 eye
for every _____ that the brain is starved for blood, 2 million neurons, 14 billion synapse and 12 kilometers of myelinated fibers are destroyed
1 minute
for every _____ in delay to reperfusion decreases the likelihood of a good outcome by 10%
30 minutes
what are the indications for reperfusion via systemic IV thrombolysis
- age >/= 18
- clinical diagnosis of ischemic stroke
- clearly defined set of sx with onset less than 4/5 hours prior to treatment
- CT scan shows no evidence of intracranial hemorrhage
a drug to restore blood flow; only for ischemic stroke
IV thrombolysis
on a perfusion scan, what does the purple and green coloring indicate
green = penumbrum (sick of dead brain)
purple = dead brain (core)
barriers to recovery following stroke
- post-stroke depression/anxiety
- pain (spasticity, shoulder subluxation, central post stroke pain, disuse and abnormal postures)
- falls
- fatigue
- changes in lifestyle
- recurrent stroke
non-modifiable risk factors of stroke
age
gender
race
eclampsia/pre-eclampsia
history of TIA/stroke
genetic risk factors for stroke
hypercoaguable state
fabry disease
sickle cell
T21
CADASIL
modifable risk factors for stroke
hypertension
dyslipidemia
diabetes
obesity
obstructive sleep apnea
tobacco use
A-fib
medication/iatrogenic
drug/alcohol abuse
vascular disease (CAD/PAD)
what is the most important modifiable risk factor for stroke
hypertension
what is the target BP reduction in hypertension
< 130/80
_____ with intensive lipid-lowering effects is recommended to reduce the risk of stroke and CV events among pts with ischemic stroke or TIA presumed to be of atherosclerotic origin; has good benefits but medication often leaves pt with severe muscle pain that is out of proportion
statin therapy
for patients with a prior history of stroke or TIA a goal of HgBA1c of ___ is resonable
7%
what percentage of patients with a stroke or TIA have sleep disordered breathing
50-75%
the risk for stroke in an asymptomatic carotid disease (CAD) is ______ as symptomatic CAD
not as high
pts with aysmptomatic carotid stenosis should be prescribed what
daily aspirin and statin
angioplasty and/or stenting is considered investigational and should only be considered when
failure of medical therapy
intracranial surgical interventions
- may consider CEA in asymptomatic pts with > 70% stenosis if the risk of perioperative MI/stroke/death is <3%; CAS may be considered in this setting but effectiveness compared to best medical management is not clear
- consider CEA or CAS in symptomatic pts with > 70% stensosis by non-invasive imaging or > 50% by cath based imaging
carotid revascularization
that is the optimal medical therapy for all pts with carotid A stenosis and a TIA/stroke
antiplatelet therapy
statin therapy
risk factor modifcation
risk factors specific to women
- pregnancy, preeclampsia, gestational diabetes, TOC use and hormone replacement
- migraine with aura, diabetes, A-fib, psychosocial stress
family risk factors
those with a parent who suffered a stroke under age 65 were at 3x higher risk for stroke
conditions associated with increased risk
sickle cell disease
T21
fabry disease
MELAS
CADASIL
intrinsic hypercoaguable state
autosomal dominant polycystic kidney disease
3 antiplatelet agents
aspirin
cilostazol
clopidogrel
for primary prevention in those with 10 years risk > 10%, may also be considered in those with CKD
- for patients with bio-prosthetic heart valve
initial agent for secondary prevention without extenuating circumstances (allergy, severe CKD, PUD)
aspirin
for primary prevention in those with peripheral arterial disease or in some cases with aspirin
cilostazol
may be considered for secondary prevention in pts who fail aspirin therapy; need to consider hypo/non-responders
clopidogrel
- nonvalvular A-fib with chads2vasc >/=2
- mitral valve stenosis and an embolic event or L artrial thrombus
- those with heart failure and ambolic event
- potentially those with hypercoaguable state
- evaluation for those with cryptogenic stroke and ESUS
anticoagulation
primary or secondary prevention in valvular A-fib and those with mechanical aortic or mitral valves
warfarin
