Ischemic strokes + TIAs Flashcards
Stroke vs TIA
Stroke:
- neurological sx lasting longer than 24 hrs
- demonstrated infarction on imaging
Transient Ischemic Attack (TIA) :
- temporary period of neurological dysfunction: brief interrruption of blood flow
- sx resolves completely and spontaneously within 24 hrs (often only minutes)
- can have infarction but will be no infarction if brain flow is rapidly restores
Cerebrovascular disease risk factors:
BLACK (2x more likely) > white*
Age >55 years *
HTN *
Smoking *
Atrial fibrillation (afib) *
Male *
Previous strokes*
anything that causes vascular pathology:
- Obesity/DM/Hyperlipidemia
- Cerebral amyloid angiopathy
- Neoplasm
- Cerebral aneurysms
- Carotid bruits
- Drug use (e.g., cocaine, oral contraceptives)
- Migraines with aura
- Hematologic disorders: multiple myeloma, sickle cell disease, polycythemia vera
types of strokes
Ischemic: 87%
- 2/3 are thrombotic: due to a clot forming at the site of atherosclerotic plaque
- 1/3 embolic: clot forms elsewhere and travels to the brain)
Hemorrhagic: 13%
- intracerebral hemorrhage: HTN, AVM
- SAH: due to aneurysms
Stroke definition: A stroke refers to the (abrupt/insidious) onset of a __________ that is caused by a __________, meaning a localized problem in the blood vessels.
General term:
A stroke refers to the ABRUPT onset of a NEUROLOGICAL DEFICIT that is caused by a FOCAL VASCULAR ISSUE (meaning a localized problem in the blood vessels)
thrombotic strokes: MCC, risk factors, types of occlusion
MCC: Atherosclerotic plaque rupture
Risk factors:
- HTN
- High cholesterol/DM
- Blood clotting disorders
- Smoking
- Recreational drug use
- Vessel trauma: ex cervical artery dissection
- dehydration
types of occlusion:
- Large vessel occlusion *: internal carotid, MCA, ACA
- small vessel occlusion: lacunar strokes
thrombotic strokes: definition and common causes
Definition: formation of a blood clot (thrombus) inside a blood vessel in the BRAIN
common causes:
- MCC: atherosclerotic plaque rupture
- LVO
- SVO: lacunar stroke - small penetrating arteries (basilar, distal vertebral)
- dehydration: increases viscosity of blood -> clots
embolic strokes: two types
Cardioembolic: 20% of all ischemic strokes
- MCC: Afib
- paradoxical embolism: venous clot from DVT -> patent foramen ovale
- bacterial endocarditis: septic emboli with multiple strokes in different areas
- others: : MI, prosthetic valves, rheumatic heart disease, ischemic cardiomyopathy
Artery-to-artery embolic stroke:
- MCC of LVO
- Aortic arch
- Common carotid bifurcation
- Internal carotid
- Vertebral artery
- Basilar artery
Cardioembolic strokes: causes, sx
Cardioembolic: 20% of all ischemic strokes
- MCC: Afib
- paradoxical embolism: venous clot from DVT -> patent foramen ovale
- bacterial endocarditis: septic emboli with multiple strokes in different areas
- others: : MI, prosthetic valves, rheumatic heart disease, ischemic cardiomyopathy
Sx: SUDDEN MAXIMUM NEUROLOGIC DEFICIENT AT ONSET
paradoxical embolization: how does it happen what imaging
Rare: VENOUS thrombi migrate to the arterial circulation
- Patent foramen ovale (PFO)
- Atrial septal defect
Imaging: bubble-contrast echocardiography
- shows Right-to-left shunting
cervical artery dissection (2% of all ischemic strokes): location, types, sx, risk factors, causes
Location:internal carotid or vertebral arteries (most heal spontaneously and don’t turn into strokes)
Type:
-Artery to artery embolus: Common in youngpts (<60 yrs)
- Complete thrombotic occlusion
Sx:
- Painful dissection preceding stroke by hours/days
Risk factors:
- Ehlers-Danlos, Marfans disease
- cystic medial necrosis
- fibromuscular dysplasia
- polycystic kidney ds
Causes:
- Trauma: MVA, sports
- Spinal manipulative therapy = vertebral artery dissection
internal carotid artery dissections vs vertebral artery dissection sx
internal carotid:
- unilateral anterior neck pain or headache around the area or frontal area w/ TIA/stroke sxs
- think this with younger person with ipsilateral pain + neurological deficits
- horners sx
- monocular blindness
- CN palsies
Vertebral artery:
- sx: occipital or posterior neck pain with TIA/stroke sxs
- cause: spinal manipulative therapy
what are some complications of strokes
- hemorrhagic transformation: ischemic damage -> increased permeability -> hemorrhagic tissue
- cerebral edema: defective ATP + increased permeability of BBB
- liquefactive necrosis: within 3-21 days
- DVT: immobile
- seizures
- pneumonia/dysphagia: intubation
- dementia
Anosognosia: def + what type of stroke would this be found in
Def: lack of awareness of illness
Found in:
- Right/non-dominant hemisphere strokes (parietal lobe): MCA
Ataxia: definition + what artery location for this sx
Ataxia: Loss of full control of bodily movements
location: Posterior circulation
- PCA
- basilar, vertebral -> lacunar strokes
Wallenberg syndrome: ipsilateral gait ataxia
stroke in Internal capsule posterior limb: Ataxic hemiparesis -> same side motor weakness + ataxia
PCA:
- Vertigo, ataxia, nausea
Ischemic penumbra: definition
Tissue surrounding the core region of infarction which is ischemic but REVERSIBLY dysfunctional:
- Maintained by collaterals
- Can be salvaged if re-perfused in time!
common signs and sx of stroke
MC: Weakness or numbness to the face, arm, leg*
Common:
- Trouble speaking or understanding
- Sudden trouble seeing in one or both eyes
- Sudden trouble walking
- Dizziness or loss of balance or coordination
- Sudden severe headache with no known cause
- Sudden confusion
The symptoms and signs inischemicattack are‘negative’in nature (i.e. loss of normal brain function) hence called “Neurologic Deficit
anterior circulation strokes vs posterior circulation strokes: incidence, which arteries, common sx
Anterior (70%): ACA, MCA, internal carotid artery
- common stroke sx: contralateral hemiparesis or speech issues
- ICA = same sx as others + amaurosis fugax
Posterior (30%): PCA, basilar, vertebral artery, PICA branch
- more subtle and tend to be missed
- Vertigo, ATAXIA, nausea, CN palsies
- Dreaded D’s: dysarthria, dysphagia, diplopia, DIZZINESS, drowsiness and DROP attacks
ACA syndrome: what areas does it supply and incidence
Areas supplied:
- Medial and superior FRONTAL and PARIETAL lobes
- Corpus callosum (partial)
- Basal ganglia (partial)
incidence: <3% of all strokes
ACA stroke syndrome: what sx
CONTRALATERAL HEMIPLEGIA: worse in LEGS > arms/hands/face*
Contralateral sensory loss (usually minimal)*
Frontal lobe dysfunction:
- Abuilia*: Absence of willpower or the ability to act decisively, may have a delay in verbal and motor responses
- urinary incontinence
- gait apraxia**: motor planning deficit that affects walking ability despite intact basic motor function of the legs
MCA syndromes: incidence and divisions
Most common occurence (70%)
M1: proximal MCA
M3 superior: lateral frontal lobe; superior parietal lobe
M3 inferior: lateral temporal lobe and inferior parietal lobe
MCA stroke syndrome: general sx
Contralateral hemiplegia: FACE/ARMS > leg**
Contralateral hemisensory loss
Contralateral homonymous hemianopia: Loss of vision in the same half of the visual field in both eyes
Ipsilateral Gaze preference: The eyes may deviate toward the side of the stroke
Dysarthria: Slurred speech due to facial muscle weakness.
MCA stroke: left/dominant vs right/non-dominant sx
Dominant/LEFT: aphasia
- superior M3 = expressive aphasia/”Broca’s”:Difficulty speaking, but good comprehensio
- inferior M3 = receptive aphasia/”wernicke’s”: Fluent but nonsensical speech, and poor comprehension; contralateral homonymous hemianopia
- M1 = global aphasia
non-dominant/RIGHT:
- Anosognosia
- Contralateral neglect
- Constructional apraxia: Difficulty in motor planning, inability to execute tasks despite understanding the instructions and having the physical capability to perform them
(ex: drawing or assembling objects)
dominant vs nondominant hemispheres (work in progress)
Left/Dominant:
- receptive aphasia: wernickes area
-
Right/Non-dominant
Right handed (90%): left hemisphere dominant
Left handed (10%): right hemisphere dominant
Typically:
- dominant = left
- non-dominant = right
ICA syndrome
- Internal carotid artery occlusion may be ASYMPTOMATIC
- Symptomatic occlusion similar to mainstem MCA stroke + preceded by amaurosis fugax*
- Often preceded by TIAs or transient monocular blindness due to ophthalmic artery branch
lacunar stroke defintion
Definition:
- small NON-cortical infarcts of a single penetrating branch of a larger cerebral artery (think internal capsule, thalamus, and brainstem)
Sx: mostly contralateral motor/sensory defects without higher cortical function
match stroke to leasion site:
- pure motor stroke
- pure sensory stroke:
- ataxic hemiparesis
- Dysarthria-Clumsy Hand Syndrome:
Pure motor stroke: internal capsule lesion
Pure sensory stroke: thalamus
Ataxic hemiparesis: internal capsule posterior limb; contralateral limb ataxia
Dysarthria-clumsy hand syndrome: pons/internal capsule; slurred speech, contralateral hand weakness, clumsiness
non-cortical regions of the brain
non-cortical: beneath the cerebral cortex
Internal Capsule: A major pathway for motor and sensory information, connecting the cortex to other parts of the brain and spinal cord (explained further below).
Thalamus: Relay station for sensory and motor signals.
Basal Ganglia: Involved in movement regulation.
Brainstem: Controls basic functions like breathing, heart rate, and arousal.
PCA stroke syndromes: what does the PCA supply
PCA: occipital lobes, inferior temporal lobes, parts of the thalamus, and midbrain
PCA stroke: sx
General:
- Contralateral Homonymous Hemianopia with MACULAR Sparing** (b/l blood supply w MCA): (lateral geniculate nucleus)
- Contralateral Sensory Loss
Dominant/Left:
- Alexia without agraphia: can’t read, can write **
- Anomia: difficulty naming objects and colors
- Visual agnosia: inability to describe what an object is used for
Non-dominant/Right: Prosopagnosia- inability to recognize faces
BASILAR artery occlusion: overview and where does it supply
Overview:
- super rare <1%
- incompatible with life: SUDDEN COLLAPSE AND COMATOSE SX
- consider it when there is DIZZINESS + neuro deficits
basilar artery supplies: midbrain, medial and lateral pons, part of the cerebellum, medial temporal and the occipital lobes
Mid-basilar occlusion
- affects the ventral pons
- can lead to LOCKED IN SYNDROME: complete paralysis (quadraplegia) + preserved consciousness/vertical eye movement
Mid basilar occlusion:
- ipsilateral CN VII palsy
- contralateral hemiparesis
Top of the Basilar Syndrome
Coma (due to ARAS involvement)*
can also have:
- Oculomotor disturbances (roving eye movements or downward/inward gaze)
- Hemianopia (loss of half the visual field)
- Bilateral ptosis (drooping of both eyelids)
- CN III palsy (pupillary enlargement with light reaction preserved)
Wallenberg syndrome
location:
- lateral medulla: occlusion of the posterior inferior cerebellar artery (PICA) -> branch of the vertebral artery
Sx:
- Dizziness, nystagmus, N/V, dysarthria, dysphagia, diplopia, HICCOUGHS*
Mixed: ipsilateral:
- CN V facial numbness
- horners syndrome
- gait ataxia
Mixed: Contralateral
- spinothalamic: loss of pain + temp sensation
horner’s syndrome: causes and 3 order neuron pathway (not too important on test)
Cause: damage to sympathetic nerve supply
- oculosympathetic pathway: 3 orders of neurons -> damage at any point will cause horners
- need huge workup
first order: hypothalmus -> spinal cord; stroke damage
second order: spinal cord -> lung apex -> neck -> cervical ganglion
- carotid dissections
- lung tumor (pancoast)
- trauma
3rd: go up internal carotid -> cavernous sinus -> innervation
Ipsilateral sx: ptosis, miosis, anhidrosis
Acute management of strokes
If hemorrhagic stroke is ruled out, thrombolytic therapy is indicated because it improves outcomes and needs to be urgently prescribed; the window for administration is only 3/4.5 hours from onset of symptoms
Stroke/TIA Initial Management Flowchart:
ABCD approach:
AIRWAY:Can they clear oral secretions & maintain airway?
BREATHING:Provide supplemental O2 if oxygen saturation is <94%
CIRCULATION:Are they hemodynamically stable?
- hypotensive: mimics stroke -> RESTORE BP
- HTN: could be ischemic vs hemorrhagic -> need IMAGING
- obtain 2 IV lines: ones for tPA, other for other drugs
- initiate labwork: need to check cardiac enzymes, CBC, lipid panel, etc
Disability:
- Perform a focused neurological exam
- obtain POC glucose to rule out hypoglycemia mimic for stroke
National Institutes of Health Stroke Scale (NIHSS)
- evaluates patients with suspected acute stroke and to make decisions about acute treatment
- Correlates with infarct size, clinical severity, and long term outcome
- ≥6 correlates with cortical stroke BUT A score of 0 does NOT mean there is no stroke!
- Not all stroke symptoms are captured by the NIHSS
- Good at identifying ANTERIOR (70%) strokes but its not as reliable for POSTERIOR circulation (30%)
- Very time-consuming
1 goal of Acute ischemic stroke:
Prevent or reverse brain injury!!!
- salvage Penumbra
tPA acute ischemic stroke complications and tx
Bleeding:
- make sure that before any tPA administration: pt is stratified beforehand
- is bleed clinically significant? - small petechial hemorrages have no change in NIHSS..
- sx of a significant bleed: Worsening neuro status, seizure, stuttering lacunar infarct, new headache, nausea, vomiting, ↑ BP
- FIRST STEP = STOP TPA -> next step: there is no single treatment universally accepted
- AHA recommended steps: Administer 6-8 units of platelets + 10 units of cryoprecipitate (rich in fibrinogen, factor VIII, and von Willebrand factor to help reverse the clotting defect) -> reimage brain emergently
- +/- consider: Pro-thrombin complex concentrates, Antifibrinolytics ( ex: TXA, tranexamic acid)
Angioedema:
- stop tPA immediately, check for ACEi use -> IV Methylprednisolone/Diphenhydramine/Famotidine
when should you not administer tPA to ischemic stroke pts
Do not administer if pt is a bleed risk!!!! or if they have hemorrhagic stroke or reversible injury!!!!
Clinical presentation:
- SBP>185, DBP>110 -> give IV labetolol or nicardipine first
- pt with active internal bleed
- sx of infective endocarditis
- stroke associated with sx of aortic dissection
Hematologic:
- Platelet count <100,000/mm
- Current anticoagulant use with INR >1.7, PT >15 seconds, aPTT >40 seconds, or PT >15 seconds
- Therapeutic doses of LMWH within the last 24 hrs
- Use of direct thrombin inhibitors or factor Xa inhibitors within the last 48 hours with evidence of anticoagulation effects on labs
Surgery:
- Ischemic stroke or severe head trauma in the last 3 months
- Intracranial or intraspinal surgery in the last 3 months.
Hx:
- Intra-axial intracranial neoplasm
- previous intracranial hemorrhage
- GI malignancy or GI hemorrhage within 21 days
simply just not indicated: hemorrhagic strokes or irreversible damage
- sx of SAH (hemorrhagic stroke)
- extensive hypodensity on CT, consistent with irreversible injury
- active internal bleeding on head CT
what is Mechanical thrombectomy (MT)
given to ischemic stroke pts with LVO within 24 hrs
Mechanical thrombectomy:
- Minimally invasive and endovascular procedure
- A catheter is guided up from the groin or radial artery, the clot is broken up, pieces are removed
- Performed by neuro-interventionalist radiologist
Transient ischemic stroke: risk stratification tool and prevention
Risk stratification tool: ABCD2
- Predicts likelihood of subsequent stroke in 2 days
- ABCD2 score <4: ASA alone
- ABCD2 score≥ 4: DAPT x 21 days
Prevent the stroke by targeting the cause/ethiology:
- Non-cardioembolic stroke= DAPT (ASA+clopidrogel or ASA+ticagrelor)
- Afib: anticoagulation - apixaban (DOAC); LMWH; warfarin
- heart thrombus: DOAC
- carotid stenosis: 50-99%= CEA or Stenting + BP control + HLD control
amaurosis fugax: description, ddx, prognosis
Description:
- Unilateral visual loss, painless, transient (20-30 min) ***
- Spontaneously self resolves **
- Curtain coming down” or “darkening”
- Complete or partial visual field
DDx:
- INTERNAL CAROTID: ipsilateral ICA ophthalmic artery branch occlusion/stenosis
- giant cell arterities
- central retinal artery occlusion/CRVO
- papilledema
- sickle cell anemia
- MS
Prognosis:
- Amaurosis fugax = harbinger of strokes -> particularly involving the carotid circulation
- needs WORKUP
amaurosis fugax: causes of occlusion, risk factors, dx
Occlusion or stenosis of the ipsilateral internal carotid artery (ICA) ophthalmic artery branch:
- Thromboembolism from carotid plaque
- Hypoperfusion from stenosis or other cause
- Vasospasms
- Increased plasma viscosity (e.g. MM)
- Atherosclerosis
Risk factors:
- >50 years old
- Vascular risk factors : HTN, HLD, DM, Smoking, TIA/CVA hx, PVD, cocaine, afib
Retinoscopy: hollenhorst plaques (arrows: cholesterol emboli) , pale retina
