Atherosclerotic CNS stuff (Pales) Flashcards
Epidemiology of Stroke
Third leading cause of death in the US
very common
deaths: black males> black females> white males> white females
leading cause of long-term disability in the US
high economic burden
Stroke definitions
CVA (cerebrovascular accident)
abrupt onset of a neurological deficit that is attributable to a focal vascular cause
2 major types of stroke
Hemorrhagic (cerebral hemorrhage)- 15%
Ischemic (cerebral ischemia)- 85%
Ishemia– from Greek. Restriction of Blood
blood in the brain
is an irritant, causes swelling (in hemorrhagic stroke, cut a hole to let the brain swell)
Ischemic penumbra
brain tissue surrounding the cerebral necrosis that exhibits reversible ischemic changes (salvageable)
causes of ischemic stroke
large artery thrombosis
embolism
Lacunar
Other (watershed infarcts, hypercoagulable disorders, vasculitis, vasospasm, dissection of artery, venous thrombosis, Moyamoya disease)
large artery thrombosis
plaque with fibrous cap–> cap ruptures–> blood clot forms around the rupture, blocking the artery
Embolic stroke- types of emboli
originating from an atherosclerotic plaque
originating from thrombus
Sources of emboli
heart
artery to artery
lower extremity DVT with paradoxical emboli
Cardiac emboli sources
Atrial: atrial fib/ flutter, atrial eptal aneurism, atrial tumors (myxoma)
Ventricular (cardiomyopathy, MI, ventricular aneurisms)
Atrial septal aneurism
weakening and out-pouching of interatrial septum, leading to stasis and thrombus formation (mural)
Atrial myxoma
pieces of tumor may tear off and become emboli
associated thrombus can embolize
Ventricular sources of emboli
cardiomyopathy
infarction
ventricular aneurisms
cardiomyopathy
Weak and dilated ventricle isn’t pumping efficiently leading to blood stasis and thrombus formation
MI (as source of embolus)
part of the wall is not moving, creating stasis and leading to mural thrombosis
can be from current or old MI
Cardiac emboli- valvular sources
rheumatic miral stenosis
prosthetic valves
infective and non-infective endocarditis
nonbacterial thrombotic (marantic- age-related) endocarditis associated with malignancies and prothrombic states
calcification of valves
bicuspid aortic valves
inflammatory valvulitis (Libman-Sacks, Behcet, Syphilis)
Artery to artery embolic infarcts
Carotid artery atherosclerosis/ stenosis- casues 5% of all strokes.
The tighter the stenosis, the higher the risk risk of stroke
May cause embolic or thrombotic type of strokes
Paradoxical emboli
originate from the L.E. deep veins
“hole” in the heart between left heart and right heart
(PFO or ASD/ VSD)
Lacunar stroke
Infarct forms in ** subcortical** areas of brain supplied by small deep penetrating arteries arising from the big arteries
may be due to atheroemboli or lipohyalinosis (fibrous tissue replacing muscle around the lacunar arteries)
HTN is major factor
frequently asymptomatic (subcortex does very little, but basal ganglia can be affected)
Lipohyalinosis
high pressure of large arteries transmitted to small arteries
hyperplasia of small vessel walls
hyalinization of the vessel walls
narrowing and occlusion of the lumen
Autoregulation of cerebral blood flow
the organs that are meant to die last when blood pressure falls: Brain and Kidneys. They have autoregulation.
Watershed infarcts
Ischemic infarct of the areas farthest from the large arteries
the most sensitive areas when perfusion decreases
Develops with conditions causing hypotension
- sepsis
- severe bleeding
- severe dehydration, etc.
Hypercoagulable disorders
Hemostasis system- 3 parts: coagulation system, anticoagulation system, thrombolytic system
hypercoagulable disorders promote coagulation over anticoagulation
most cause venous clotting but some favor arterial
examples:
Factor V Leiden mutation (most common) Protein C deficiency Protein S deficiency Antithrombin deficiency Plasminogen deficiency Prothrombin gene mutation
disorders more likely to cause arterial clotting
antiphospholipid antibody syndrome .
- Anticardiolipin antibodies (ACA)
- Lupus anticoagulants (LA)
Hyperhomocysteinemia
Other hypercoagulable states
Cancer (pancreatic, lung)
pregnancy and exogenous estrogen use (including use of oral contraceptive pills-birth control pills)
hormone replacement therapy
prolonged bed rest or immobility, heart attack, stroke and other illnesses that lead to decreased activity
myeloproliferative disorders such as polycythemia vera or essential throbocytosis
vasculitis
inflammatory condition –> thickening of arterial wall–> decreased lumen –> CNS restricted blood flow
Vasospasm causes
- Cocaine (fries both cortices)
2. After intracerebral bleeding (subarachnoid bleeding)
disection
often traumatic causes (golf, chiropractic, etc.)
Moyamoya disease
= “smoke puff”
poorly understood.
occlusive disease involving large intracranial arteries
Venous stroke
DVT in one of the venous sinuses
may be ischemic or hemorrhagic
usually associated with severe headaches and neurological symptoms
hemiparesis
weakness of one side of the body
hemiplegia
complete paralysis of one side of the body
homonymous hemianopsia (hemianopia)
loss of vision in the same visual field of both eyes
acalculia
difficulty to perform simple math tasks
agnosia
inability to recognize objects, persons, sounds, shapes, or smells
aphasia
inability to speak (motor or sensory)
alexia
inability to read
agraphia
inability to write
dysphagia
difficulty swallowing
dysarthria
slurred speech
hemispatial neglect
inability to attend to one side of the body or visual field
apraxia
inability to perform a specific task
anosognosia
unawareness of or denial of the existence of disability
anomia
difficulty with recalling words or names
ataxia
unsteady gait
MCA Syndrome
Contralateral hemiplegia/ sensation loss (sometimes in face and upper extremity only)
contralateral homonymous hemianopsia
Dominant side: aphasia, alexia, agraphia, acalculia, finger agnosia, and right-left confusion
Non-dominant side: unilateral neglect, dressing apraxia, anosognosia, and constructional apraxia
ACA syndrome
Contralateral sensory and motor loss of lower extremity
PCA syndrome
Homonymous hemianopsia
alexia without agraphia
visual or color anomia
lateral pontine syndrome (Marie-Foix Syndrome)
anterior inferior cerebellar artery
ataxia- arm and leg
weakness- upper and lower extremity
hemisensory loss- pain and temp
lateral medullary syndrome (Wallenburg)
Posterior inferior cerebellar artery Facial sensory loss and pain Ataxia Nystagmus Vertigo Hoarseness Dysphagia Horner syndrome Hemisensory loss Hiccups
Basilar artery strokes
Locked-in Syndrome
- Quadriplegia, bilateral facial paralysis, dysarthria
Lateral pontine syndrome (Marie-Foix Syndrome)
Ventral pontine syndrome (Raymond Syndrome)
- Lateral gaze weakness
- Contraletaral hemiplegia
Ventral pontine syndrome (Millard-Gubler Syndrome)
- contralateral - upper and lower extremity weakness
- Ipsilateral facial weakness
Ataxic hemiparesis
- Contralateral upper and lower extremityweakness and ataxia
Cortical blindness (Anton Syndrome) - (blindness and denial)
Other symptoms of stroke
headache
nausea/ vomiting
stupor/ coma/ amnesia/ confusion/ delerium
amaurosis fugax
transient mono-ocular blindness
often warning sign of an impending stroke
several causes:
- embolic (most often from carotid artery of the same side)
- hemodynamic
- ocular
- neurologic
- idiopathic
opthalmic artery
is the first branch of the carotid before it goes to the brain
thus amaurosis fugax is often the first warning sign of impending stroke
TIA
AKA “mini-stroke)
the same symptoms (and detiology) as with stroke but lasting less than 24 hours
15-45% –> infarcts
patients with TIA have 10% risk of CVA within first 3 months
Dx of stroke
History: sudden onset, symptoms described previously
Complete neurological and mental status exam
CT of brain (without contrast) is the quickest way- only detects big strokes. to R/O bleed (because we want to treat with blood thinners)– takes 5 minutes
MRI of brain is very sensitive– takes 45 minutes
assessing the cause of stroke
History: look for risk factors lipids, blood glucose, cardiac enzymes EKG- arrhythmia, MI Echocardiogram (transthoracic or transesophageal)- intracardiac thrombosis, cardiomyopathy, valvular disorders, ASD Carotid Doppler- carotid stenosis MR-A/ CT-A
Differential Dx of ischemic stroke
hemorrhagic stroke/ subdural hemorrhages seizures complex migraines CNS tumors nerves palsy, peripheral neuropathy encephalitis toxic metabolic encephalopathy syncope vertigo
most common cause of mental status change in hospitalized patients
toxic metabolic encephalopathy
acute treatment of stroke
activation of STROKE ALERT TEAM (time is brain)
medications
- rtPA (intra-venous and catheter-directed intraarterial)
- antiplatelet agents- ASA, clopidogrel, aggrenox (ASA/ dipiridamole)
IV fluids
heparin- select cases (known visible thrombus, dissection, staggering CVAs) - causes a lot of bleeding
Keep BP sufficient for saving penumbra but not too high- permissive HTN
Swallowing evaluation
Early rehabilitation
clot buster rtPA works on
plasminogen–> plasmin
Stroke risk factors - modifiable
HTN Arial fib smoking diabetes carotid stenosis (increases risk 2 times if no previous TIA or CVA) Hyperlipidemia (increases risk 2-2.5 times) Physical inactivity and obesity Alcohol and drug abuse Geographic location US South-East has more strokes Socioeconomic factors
stroke prevention
Diet- low in sat fat
exercise- aerobic exercises 30-60 minutes/ day, most days
Strict control of Blood Pressures, Blood sugars, blood cholesterol
Quit smoking
meds:
- antiplatelets. Aspirin, clopidogril
- anticoag agents: warfarin, heparin and LMWH, new oral anticoag drugs: dabigtran, rivaroxaban, apixaban, edoxaban
treatment options of carotid stenosis
depends on degree of stenosis and on h/o CVA
medical treatment (treat risk factors)
surgical treatment with carotid endarterectoy
stents - only for lesions not reachable with surgical approach
- Patients have high surgical risk
carotid endarterectomy
atherosclerotic plaque removed from carotid artery to restore blood flow to brain
Stroke Risk FactorsNon-modifiable
Age.
- Risk doubles with each decade after 55
Heredity (Family history)
Race
- African Americans and Hispanics higher than Caucasians
Gender
- More men has strokes in a given year in each age group
- More than half of total stroke deaths occur in women
Personal h/o TIA, CVA, MI, any atherosclerosis
Ischemic stroke - general
extremely common cause of death and disability in the US
There are multiple causes of ischemic stroke; embolic, lacunar and thrombotic being the most common ones
In both TIA and CVA it’s important to know the type of stroke and the source of emboli, as it will determine the acute treatment and the means for secondary prophylaxis
Atherosclerosis and Hypertension
are major risk factors for strokes.
Hypertension is the main cause of lacunar (small vessel) strokes.
Symptoms of the stroke depends on the location and size of the vessel involved
TIA
a transient ischemia or small CVA when all symptoms are resolved within 24 hours.
The same patient may have several CVAs of different etiology as the risk factors for different conditions are similar.
Always look at the patient’s symptoms and match them with the stroke location on MRI
If location of stroke is in the territory of more than one particular artery, think
embolic and think about the source upstream
It’s always important to consider differential diagnosis
CT of the brain
is used for diagnosing large strokes and to r/o bleeding for tPA administration, but may miss early strokes, especially if it’s small or in posterior circulation.
tPA
is a one of the major treatment of the ischemic stroke, but full of complexities and controversies
