Stroke Flashcards
What is a stroke?
- An acute, rapidly-developing focal neurological dysfunction due to an abnormal perfusion
- Interruption of the normal blood supply to the brain (ischemia), resulting in neuro dysfunction and the death of brain cells
What are the two emphases and the de-emphasis of the AHA/ASA definition of stroke?
- Imaging
- Neurological deficits
De-emphasis of temporal aspects, like sx lasting for greater than 24 hours
What types of infarctions does the definition of stroke include?
- Cerebral infarctions
- Spinal infarctions
- Retinal infarctions
Clinically, stroke continues to be used to refer to cerebral infarctions
What is the most common type of stroke?
Ischemic stroke, about 87% of all strokes
What is an ischemic stroke?
A stroke due to thrombosis, embolism, or systemic hypoperfusion
Where is the most common site of an ischemic stroke?
Middle cerebral artery (MCA)
What is an important warning signs of a stroke?
Transient ischemic attacks (TIA)
What are some cardioembolic causes of ischemic stroke?
***AFIB*** Ventricular thrombus Prosthetic valves Rheumatic heart disease Other cardiac sources
What is the second most common type of stroke?
Intracerebral hemorrhage (ICH), about 10% of all strokes
What is an intracerebral hemorrhage?
Bleeding inside the brain
What is the third most common type of stroke?
Subarachnoid hemorrhage (SAH), about 3% of all strokes
What is a subarachnoid hemorrhage?
Bleeding in the subarachnoid space
Stroke is the what # leading cause of death in the United States?
Fifth leading cause of death
What is the leading cause of disability?
Stroke
Who has a higher lifetime incident of stroke: females or males?
Females
Of younger people, who is more likely to have a stroke: a female or male?
Male
What is a major risk factor for stroke?
Age, particularly 75 and older
Who is more likely to die from a stroke?
Non-Hispanic black Americans and those living in the southern state “stroke belt”
What is the cause of the decline in stroke deaths?
A decrease in both stroke incidents and stroke mortality
- Improved blood pressure control
- Reduced smoking
- Improved diabetes control
- Improved lipid control
What are the different clauses of the stroke?
- Thrombus
- Embolus
- Small vessel disease
- Hypoperfusion
- Hyper viscous blood
- Cryptogenic
Where and how does a thrombus occur?
- Within cerebral vasculature
- Usually starts when atherosclerotic plaque becomes unstable, similar to MI
What causes an embolus formation, and where are these typically found when someone has a stroke?
- Usually of cardiac or carotid origin
- Atrial fibrillation
- Large cerebral artery occlusion is typically embolic
- Valvular thrombi: mitral stenosis, endocarditis, or prosthetic valve
What kinds of infarcts are associated with small vessel disease?
Lacunar Infarcts
What are some causes of cerebral hypoperfusion?
Low blood pressure
Decreased cerebral perfusion pressure
What are some hyperviscous blood state/conditions?
Sickle cell disease
Polycythemia vera
What is the cryptogenic stroke?
And ischemic stroke for which no probable causes identified after adequate diagnostic evaluation
What is the standard diagnostic work up for a stroke?
- MRI or CT of brain
- CTA or MRA of the brain, neck, and thoracic arteries; ultrasound if CTA and MRA contraindicated or unavailable
- TTE, TEE
- ECG, Holtor monitor, 30 day event monitor, loop recorder
- Hematologic testing for hypercoagulable states
- Occult “low burden” paroxysmal AF maybe found: significance unclear
- Patent foramen ovale (PFO) maybe found
What is the risk of closing a PFO?
New onset atrial fibrillation
What are the nonmodifiable risk factors for stroke? What is the single most important nonmodifiable risk factor?
- Age: single most important nonmodifiable risk factor
- Sex: higher lifetime incidence older females > older males
- Race and ethnicity: AA, Latino, Native Americans > Non-Latino white, Asian) - These populations can be more risk for sickle cell disease as well
- Family history: an ischemic stroke in either parent by the age of 65 is associated with a 3 fold increased risk of stroke in offspring
- A prior stroke or TIA
What are some modifiable risk factors for stroke?
The things that keep hearts healthy keep brains healthy
- Hypertension: BP > 140/90
- Diabetes: Doubles risk, particularly increases risk of stroke a younger age, Duration of diabetes also matters
- Atrial fibrillation: Increases risk fivefold
- Carotid artery stenosis: Risk doubles
- Hyperlipidemia: Relationship to stroke risk unclear, especially in those that are older
- Smoking: 2 to 4 times greater risk
- Heavy alcohol use: Low and moderate use is associated with decreased risk
- Physical inactivity
- Chronic kidney disease: Proteinuria and albuminuria are better predictors of stroke risks than GFR
- Obesity: Unclear, Most likely related to other risk factors present with obesity
- Sleep apnea: Relationship is bidirectional, as stroke increases the risk of sleep apnea as well
In those with atrial fibrillation with had a stroke, where are the blood clots most commonly formed?
Left atrial appendage of the heart
What is the most important modifiable risk factor in preventing SAH?
Smoking
What are some modifiable risk factors for stroke that are related to females in particular?
- Migraine with aura
- Use of oral contraceptives
- Use of HRT
What are some general interventions for primary prevention of stroke?
- Obtain a complete family history
- Screen for stroke risk using modified Framingham stroke risk calculator
- BP < 140/90
- Smoking prevention and cessation
What are some specific primary prevention recommendations for those with diabetes?
- BP < 140/90
- Staten, not a fibrate
- General glycemic control
What are some specific primary prevention recommendations for those with Hyperlipidemia?
- Lifestyle changes and treatment with a statin for those with high 10yr ASCVD risk
- No evidence that fibrates or any other lipid lowering agents reduced risk of stroke
What are some specific primary prevention recommendations for those with atrial fibrillation?
- Screen everyone 65+ (Pulse plus ECG is indicated)
- In nonvalvular AF at high risk, anticoagulation with a DOAC/NOAC, like Pradaxa, Eliquis, Xarelto, Savaysa is preferred over warfarin
- In nonvalvular AF at moderate risk, no anti-thrombotic therapy, can be considered
- For those at low risk, aspirin is no longer recommended
- Watchmen left atrial appendage closure device now available for some patients that would otherwise need long-term warfarin therapy
What criteria are used to determine which patients with AF are at high, moderate, or low risk of stroke?
CHA2DS2-Vasc
- Congestive heart failure (1 point)
- Hypertension (1 point)
- Age 65-74 (1 point), Age 75+ (2 points)
- Diabetes (1 point)
- Stroke or TIA (2 points)
- Sex (female) (1 point)
- Vascular disease (MI, PAD, aortic plaque) (1 point)
Low risk: 0 points if male, 1 point if female
Moderate risk: 1 point if male, 2 points if female
High-risk: >2 points if male, >3 points if female
What are some specific primary prevention recommendations for those with Carotid artery stenosis?
- Asymptomatic: aspirin plus statin
- Revascularization is dependent on comorbidities, life expectancy, and other factors
- Can consider carotid endarterectomy in asymptomatic patients who have >70% stenosis of Internal carotid artery - Effectiveness compared to medical management alone is not well-established
What are some specific primary prevention recommendations related to lifestyle changes?
- Diet: Mediterranean diet supplemented with nuts
- Exercise: Moderate to vigorous intensity aerobic physical activity at least 40 minutes per day for 3 to 4 days a week
- Obesity: Weight reduction
- Alcohol: Reduction or cessation by heavy drinkers, one to 2 drinks per day for males and one drink per day for females
What are some specific primary prevention recommendations for those with Sleep apnea?
- Screen for sleep apnea
- Treatment
What do studies show about prophylactic aspirin’s risk of bleeding versus benefits?
Risk of bleeding outweighs the benefits
- No CVD benefit from Aspirin, but statistically significant higher risk of bleed
- Increased risk of major bleeding, intracranial bleeding, and major gastrointestinal bleeding
What does the NIH stroke scale measure and what do the scores mean?
11 items: Level of consciousness, best gaze, visual fields, facial palsy, motor arm, motor leg, limb ataxia, sensory, best language, dysarthria, extinction and inattention
- Maximum possible score is 42
- Scores > 20 are considered severe
What is the name of the area of the brain that maybe saved if perfusion to brain tissue is restored quickly?
penumbra
What happens intracellularly during an ischemic stroke?
- Neurons cannot maintain a aerobic respiration –> anaerobic respiration and the accumulation of lactic acid
- Neurons cannot maintain a ionic balance
- Glutamate, the chief excitatory neurotransmitter, excessively stimulates the neurons and depolarizes the cellular membrane
- Sodium, chloride, and water flow into the cell –> cytotoxic edema
- Calcium flows into the cell –> neuronal death
- Stroke is not just an event, it is a process that evolves over time*
What treatment option can extend the time for reperfusion beyond tPA’s 3-4.5hr hour window?
Mechanical thrombectomy
What are some characteristics of patients appropriate for mechanical thrombectomy?
- Large vessel occlusion, Either internal carotid or proximal middle cerebral artery
- Area of infarct that was relatively small, Compare to the penumbra/hyperperfused/ischemic tissue
What does the frontal lobe of the brain control?
- Skeletal muscle movement
- Behavioral expression
- Broca’s area
What does the parietal lobe of the brain control?
- Sensory cortex
- Damage can affect superior contralateral vision
What does the temporal lobe of the brain control?
- Smell and hearing
- Damage can affect inferior contralateral vision Wernicke’s area
What does the occipital lobe of the brain control?
Primarily controls vision
What is the difference between Broca’s aphasia and Wernicke’s aphasia?
- Broca’s area is located on the frontal lobe of the left hemisphere = Nonfluent or expressive aphasia
- Wernicke’s area is located on the temporal lobe of the left hemisphere = Fluent or receptive aphasia
What are the 3 parts of the basal ganglia and what is their primary role?
- Caudate, putamen, and globus pallidus
- Coordination of movement
What are the 3 parts of the limbic system and what are their roles?
- Amygdala, cingulate gyrus, and the hippocampus
- Amygdala, cingulate gyrus = Memory and emotion
- Hippocampus = Memory, especially for converting short-term to long-term memory, and learning
What are the 3 parts of the diancephalon, where is it located, and what are their roles?
- Thalamus, hypothalamus, and pituitary and pineal glands
- Located between the brain stem and the cerebrum
- Thalamus is crucial to sensory function and is connected to all the major areas of brain
- Hypothalamus is critical for autonomic and endocrine functions
- Pineal gland is important in sleep/weeks cycles
- Pituitary gland controls may normal functions
Where is the cerebellum located and what is its role?
- Adjacent to the brainstem
- Crucial for motor function, especially coordination, balance, and position sense
- Also affects speech and ocular movement
What are the 3 parts of the brain stem and what are their roles?
- Medulla, pons, and midbrain
- Crucial in controlling breathing, blood pressure, and alertness
- 10 of the cranial nerves arise in the brain stem
- In the medulla, the corticospinal tracks traverse midline, decussate, and send impulses to the opposite side of the body
The anterior cerebral arteries supply which brain structures?
- Surface branches supply cortex and white matter of inferior frontal lobe and medial surface of the frontal and parietal lobes
- Penetrating branches supply the deeper cerebrum, diencephalon, and limbic structures
The middle cerebral arteries supply which brain structures?
- Surface branches supply all four lobes of the cortex
- Penetrating branches supply deep white matter and part of the diencephalon
Occlusion of the MCA predominately affects which parts of the body?
The face and upper limb sensory and motor function
Occlusion of the ACA predominately affects which parts the body?
Lower limb function
The vertebrobasilar system (vertebral + basilar artery) supply which brain structures?
- Cerebellum
- Brainstem (Ponds, Medulla)
- Thalamus
- Occipital lobe
The basilar artery branches into 2 posterior cerebral arteries that supply
- Occipital and temporal lobes
- Parts of the thalamus and midbrain
The superior cerebellar arteries supply which brain structures?
- Cerebellum
- Parts of the midbrain
The posterior inferior cerebellar arteries supply which brain structures?
- Cerebellum
- Medulla
The anterior inferior cerebellar arteries supply which brain structures?
- Cerebellum
- inner ear (important diagnostic key: sudden deafness)
What is the lacunar stroke?
The occlusion of a deep penetrating artery branching off of a larger artery, such as the MCA, also known as “small vessel occlusions” or “small vessel disease”
What is a major contributing factor of lacunar strokes?
- Hypertension
- Smoking
- Diabetes
How do lacunar strokes often present?
Often clinically silent and discovered incidentally on brain imaging
- Not usually cortical signs, Often just weakness or just numbness
What are some other medical problems that may mimic a stroke?
Seizure Hypoglycemia Migraine Hyponatremia Brain tumor Meningitis/encephalitis DKA/HHS Drug toxicity Meniere's, labyrinthitis Bell's palsy Hypotension
What are some common sequelae of a stroke in an older adult?
Hemiparesis Inability to walk without some assistance Cognitive deficits Depressive symptoms Aphasia Dependent in some or all ADLs In a nursing home
What are some LESS common sequelae of a stroke in an older adult?
Seizures
Pneumonia from dysphasia or immobility
Incontinence
UTI
Spasticity or contracture
Shoulder displacement and/or shoulder pain
Post stroke pain more generally, especially central pain
Pressure wounds, depending on the level of disability
What is an important poststroke sequelae to screen for in older adults?
Depression
One third of all stroke survivors experienced poststroke depression
How can a stroke precipitate or potentiate frailty?
Immobility Deconditioning Osteoporosis Muscle atrophy Risk for pressure ulcers Risk for DVT
How much rehab must somebody be able to tolerate for admission to an acute inpatient rehabilitation?
Three hours per day
When does the neurological recovery peak? How long may some improvement be seen?
- Three months
- Three years
What is a transient ischemic attack?
A transient episode of neurological dysfunction resulting from focal brain, spinal cord, or retinal ischemia, without acute infarction
What diagnostic tests should be performed when someone is suspected to have a TIA?
- Diffusion weeded MRI within 24 hours of symptom onset
- US, MRA, or CTA for extra cranial vasculature
- Can consider transcranial doppler, but angiography is the gold standard
- ECG
- Telemetry or Holter
- Echocardiogram or TTE
- CBC, CMP, PT/PTT, lipid panel
What should someone be hospitalized for a TIA?
Patient present within 72 hours and
- ABCD2 score > 3
- ABCD2 score 0-2 and uncertainty that diagnostic workup can be accomplished in two days as an outpatient
- ABCD2 score 0-2 and other evidence that the TIA was caused by focal ischemia
Hot how do you calculate an ABCD2 score?
- Age: 1 point for age 60+
- Blood pressure > 140/90: 1 point
- Clinical features: 2 points for unilateral weakness, 1 for speech disturbance without weakness
- Duration of symptoms: 1 point for 10 to 59 minutes, 2 points for 60+ minutes
- Diabetes: 1 point
0-3: Low risk
4-5: Moderate risk
6-7: High risk
What is the most important intervention for secondary prevention of ischemic stroke?
Hypertension, goal <140/90 (lacunar <130)
How do we manage hyperlipidemia and secondary prevention of stroke?
Intensive statin therapy, even in patients with low cholesterol and no evidence of the other heart disease
When should CEA be considered for carotid stenosis and secondary prevention of stroke?
- For ipsilateral severe stenosis of 70 to 99%, CEA recommended if mortality risk less than 6%
- For ipsilateral stenosisThat is moderate50 to 69%, CEA recommended depending on age, sex, comorbidities, and same morbidity as above
- If stenosis less than 50%, there’s no indication for CEA
How do we manage carotid stenosis for secondary prevention strip?
Antiplatelet therapy, statin therapy, and risk factor modification
In order adults greater than 70 years old, is CEA or CSA better?
CEA is associated with better outcomes
For those with atherosclerosis of a major intracranial artery, is aspirin or warfarin recommended? How about clopidogrel?
- Aspirin 325 mg is recommended over warfarin
- Adding clopidogrel for 90 days maybe reasonable
What is the secondary prevention treatment of stroke in relation to atrial fibrillation?
- Prolonged rhythm (~30 days) monitoring for those with cryptogenic stroke
- Anticoagulant (DOAC/NOAC) initiated within 14 days of AF diagnosis
- For those with CAD, an antiplatelet can be added to anticoagulant
- If unable to take anticoagulants, aspirin should be initiated and clopidogrel is reasonable to add
- Is anticoagulant therapy must be interrupted, Bridge with low molecular weight heparin
What anti-thrombotic therapy should be used if the stroke was non-cardioembolic?
- Antiplatelet rather than anticoagulation
- Aspirin + dipyridamole or clopidogrel monotherapy acceptable
- Aspirin + clopidogrel not recommended, as bleeding risk too high
If someone had an ischemic stroke while taking aspirin, will increasing the dose of aspirin help?
No, nor will choosing another single agent or combo
How do you manage anticoagulation after intracranial hemorrhage or subarachnoid hemorrhage?
- Discontinue all anticoagulants for at least one week
- Decision to restart depends on risk of subsequent thromboembolism or risk of recurrent cerebral bleed
