Ischemic Stroke Diagnosis and Treatment

Objectives

• Brain Anatomy Refresher is an objective
• Recognize a stroke as separate objective
• Look at stroke epidemiology
• Understand the pathophysiology of stroke
• Identify risk factors for stroke
• Discuss immediate stroke evaluation and treatment
• Determine how to localize the lesion
• Outline further steps in stroke care
• Know the pathophysiology and risk factors for stroke
• Discuss immediate evaluation and treatment for stroke again
• Consider further steps in stroke care again
• Discuss aneurysms with pathophysiology
• How to evaluate an Aneurysm
• Review aneurysm treatment
• Discuss aneurysm screening
• Learn all about TIAs

Anatomy

• Meninges consists of the Dura Mater, Arachnoid, and Pia Mater

• Brain consists of the Cerebrum, Cerebellum, and Brainstem

• Cortex is the portion of the brain surrounded by grey matter

• Grey matter is mostly neuron cell bodies

• White matter is mostly an axon portion of a neuron

• Arterial blood supply to the brain comes from the Basilar artery, Internal Carotid arteries, Vertebral arteries, External Carotid arteries, Common Carotid arteries, Subclavian arteries, Innominate artery, and Aorta, which form the Circle of Willis

• Venous blood flows from the Cortical Vein, Superior Sagittal Sinus, Inferior Sagittal Sinus, Anterior Intercavernous Sinus, Posterior Intercavernous Sinus, Ophthalmic Vein, Sphenoparietal Sinus, Cavernous Sinus, Basal Vein of Rosenthal, Superior Petrosal Sinus, Basilar Venous Plexus, Thalamostriate Vein, Internal Cerebral Vein, Thalamostriate Vein, Vein of Trolard, Internal Cerebral Vein, Superficial Middle Cerebral Vein, Vein of Galen, Vein of Labbe, Basal Vein of Rosenthalm, Sigmoid Sinus, Sigmoid Sinus, Transverse Sinus, Straight Sinus, and Jugular Vein

Stroke

• 795,000 strokes occur in the US each year
• 185,000 people who have strokes have had a previous stroke, almost 1/4

Pathophysiology of Stroke

• Ischemic strokes comprise 87% of strokes

• Hemorrhagic strokes account for around 10-15% of strokes

• Cerebral Venous Thrombosis is rare, affecting 5-12 per 1,000,000 people

• An ischemic stroke is an infarction of central nervous system tissue attributable to ischemia

• An ischemic stroke can involve the brain, spinal cord, and retinal cells

• Ischemic strokes can be thrombotic

• Ischemic strokes can be embolic

• Systemic hypo-perfusion presents as an ischemic stroke

• In Thrombotic strokes, Thrombus formation in an artery that reduces blood flow distally

• Embolic strokes occur when an embolic piece breaks off and gets stuck downstream.

• Large Vessel strokes can happen in the extra-cranial and intracranial arterial system

• Large Vessel strokes can involve atherosclerosis which is most common, Vasoconstriction that is intracranial, Dissection (both), Arteriitis, fibromuscular dysplasia, myamoya syndrome

• Small Vessel strokes involve smaller penetrating arteries arising from the larger arteries

• Small Vessel strokes can be Lipohyalinosis as lipid hyaline builds up due to hypertension

• Embolic strokes involve the piece of debris getting stuck

• Embolic stroke may come from a cardiac source, possible cardiac or aortic source, arterial source, unknown source

• Systemic Hypo-perfusion involves a circulatory "pump failure" problem

• No cardiac output from cardiac arrest, or arrhythmia

• Reduced cardiac output includes- MI, PE, pericardial effusion, or blood loss in system hypo-perfusion

• Whole brain becomes affected rather than one isolated area

• Hemorrhagic strokes involve permanent tissue injury caused by hemorrhage

• Intracerebral hemorrhage (ICH) happens when bleeding directly happens to the brain tissue

• Subarachnoid hemorrhage (SAH) happens when bleeding happens to the space between the brain and the arachnoid mater

• The mechanism of brain tissue damage is from:

  • Hematoma formation
  • Edema around the bleed
  • Breakdown of the blood-brain barrier from excitotoxic inflammatory processes
  • Mass effect, increased intracranial pressure, and decreased cerebral perfusion = ischemia

Cerebral Vein and Dural Sinus Thrombosis (CVT)

• Thrombosis obstructs blood drainage from brain tissue
• Increased venous pressure increases cerebral blood volume
• Disruption of blood-brain barrier, leaks plasma into interstitial space, localized edema and possible venous hemorrhag
• Higher intracranial pressure decreases cerebral blood flow

Risk Factors for stroke

• Age increases stroke risk and is non-modifiable
• Low birthweight (<2500g is a higher risk than > 4000g)
• Race, Black, Hispanic/Latino & Native Americans have a higher stroke risk
• Parent with stroke before 65 is 3x higher risk
• Modifiable Risk Factors
  • Physical inactivity
  • Dyslipidemia
  • HTN
  • Obesity
  • Diabetes
  • Current smoker
  • Sickle cell disease
  • Carotid artery stenosis
  • Atrial fibrillation
  • Heart disease
  • Acute MI / Cardiomyopathy

Stroke Evaluation

• The Big Three

  • Is this a stroke?
  • Where is the lesion?
  • What is the mechanism?

• Immediate evaluation must happen and hours are important

• What can be done over 1-2 days.

• The differential diagnosis for a stroke

  • Metabolic disturbance which can be hypoglycemia
  • Migraine aura
  • Seizure with Todd paralysis
  • CNS tumor or abscess
  • Head trauma
  • Multiple Sclerosis
  • Posterior reversible encephalopathy syndrome (PRES)
  • Hypertensive encephalopathy
  • Reversible cerebral vasoconstrictive syndrome (RCVS)
  • Subdural hematoma
  • Syncope
  • Systemic infection
  • Intoxication - drug, alcohol, toxin
  • Transient global amnesia
  • Viral encephalitis
  • Wernicke encephalopathy

• Immediate Stroke Evaluation Involves Taking A History

  • Obtain history from patient, family members, EMS, any witnesses, and medical records.
  • Determine when symptoms started and are they still present?
  • 4.5 Hr to tPA, up to 24 hours for mechanical thrombectomy.
  • What are their symptoms?
  • What medical conditions do they have or meds do they take?
  • Recent trauma?
  • Recent drug or alcohol abuse?
  • Thunderclap headache?

• The stroke physical exam involves

  • Vital signs - BP, HR, O2 sat, RR, temp.
  • Cardiac exam- murmurs, bruits in neck, and arrhythmia
  • Neurological exam - created a consistent pattern
  • CN 2-12
  • Visual fields, pupils, and nystagmus
  • Sensation to light touch
  • Motor strength
  • Coordination - (heel-shin, finger-nose)
  • Rapid alternating movements
  • Rhomberg/pronator drift
  • Leg drift
  • Reflexes
  • Gait

• Immediate Stroke Evaluation using the Glasgow Coma Scale

  • Includes measurements of:
  • Eye Opening Response,
  • Verbal Response, and
  • Motor Response

• Minor Brain Injury = 13-15 points

• Moderate Brain Injury = 9-12 points

• Severe Brain Injury = 3-8 points

• Immediate Stroke Evaluation Also Requires Labs Including

  • Glucose
  • Complete blood count
  • Prothrombin time/INR
  • aPTT
  • Direct factor Xa activity assay (if taking factor Xa inhibitor)
  • Pregnancy test
  • Basic Metabolic Panel
  • Liver function test
  • Blood alcohol level
  • Toxicology screen
  • Troponin

• Immediate Stroke Evaluation Needs Brain Imaging Including

  • Non-contrast brain CT or MRI
  • Rule out ICH/SAH that has a different treatment pathway
  • Identify area of tissue damage indicating an infarct
  • Identify stroke mimics
  • ECG/Cardiac Monitoring

• How To Find The Lesion

  • History and Physical helps as the area of the brain that is damaged will result in certain patterns of symptoms
  • Imaging aids but may show nothing
  • Correlate which symptoms match with findings on imaging

• Lesions Locations

  • Cerebrum which contains cortical structures
  • Subcortical structures are lacunar strokes
  • Brain stem
  • Cerebellum

• Anterior Cerebral Artery Structure and Symptoms

  • Prefrontal Cortex- executive functions personality, decision-making, planning, complex behavior
  • Personality changes
  • Difficulty planning/organizing
  • Supplementary Motor Area- is responsible for speech production, micturition inhibition, and changing between behaviors
  • Transcortical motor aphasia or motor/sensory aphasia
  • Urinary incontinence
  • Paracentral Lobule is responsible for sensory and motor for lower limb
  • Contralateral lower limb weakness
  • Contralateral lower limb paresthesia/numbness

• Middle Cerebral Artery Structure and Symptoms

  • MCA Superior/Inferior division
  • Primary motor and sensory cortex
  • Contralateral face and arm paresthesia/numbness, spares lower extremity and upper face
  • Contralateral face and arm motor weakness spares lower extremities and upper face
  • Broca's Area handles the production of speech while Wernicke's Area handles comprehension of speech
  • Dominate side (commonly left) aphasia which can be fluent or non-fluent
  • Association sensory area Non-dominate side (commonly right) contralateral spatial neglect, seen in the clock example

• Posterior Cerebral Artery

  • Superficial PCA
  • Primary and secondary visual area
  • Contralateral homonymous hemianopia
  • Contralateral visual neglect a similar effect as spatial neglect
  • Deep PCA
  • Thalamus which is a relay center, carries ascending sensory and descending motor pathways between cortex and the body
  • Contralateral paresthesia or numbness of face, limbs, trunk (touch, pin prick, and position sense)
  • Contralateral weakness is less common
  • Splenium of corpus collosum carries connections between occipital lobes
  • Alexia without agraphia

Case Study

• 50 yo male walks into urgent care because his sister made him come for partial loss of vision
• Vitals: BP 125/84, HR 78 and regular, RR 17, Temp 97.9, O2 sat 97%
• Doesn't take any medications
• Doesn't like to come to the clinic because always find something wrong
• Smokes 1ppd for 33 years, sober for 10 years from alcohol
• What hx do you want to know?
• What physical exam do you want to do?
• Any lab work needed give you have access to any labs you can think of?
• Any imaging needed you have immediate access to CT? And same-day to MRI?

Sub-cortical Stroke

• Lacunar strokes are small cavities/holes
• 2-15mm in size
• Occlusion of a single penetrating branch
• Basal Ganglia (putamen, globus pallidus, caudate), thalamus, internal capsule
• Lenticulostriate branches of ACA and MCA

Lacunar Stroke

• Has syndromes and NO cortical signs of aphasia, hemianopsia, agnosia, neglect, and apraxia
• Pure motor hemiparesis comes with contralateral weakness involving face, arm, and leg on one side with NO sensory loss
• Pure sensory stroke comes with contralateral numbness of face, arm, and leg on one side with NO motor deficit.
• Ataxic hemiparesis has contralateral weakness and clumsy voluntary movements out of proportion to the motor deficit when weakness and clumsiness are on the same side
• Sensorimotor stroke has contralateral weakness AND numbness of the face, arm and leg with weakness and numbness and the same side
• Dysarthria is a clumsy hand syndrome with facial weakness, dysphagia, dysarthria, and contralateral slight weakness and clumsiness of one hand with NO sensory deficits

Brainstem Stroke

• Crossed findings are common, think brainstem.

• Lef vs Right, Cranial nerve findings are ipsilateral, with body affectations

• Vertical localization uses cranial nerves

• Midbrain CN 3-4

• Pons CN 5-8

• Medulla CN 9-12

• Medial vs Lateral localization needed

• 4 Medial structures:

  • Motor pathways that go to the body from the corticospinal tract
  • Medial lemniscus for fine touch, vibration and proprioception
  • Medial longitudinal fasiculus coordinates the movements of eyes so they move together
  • Motor component of CN 3, 4, 6, and 12

• Spinocerebellar tract (coordinate movement)

• Spinothalamic tract (crude touch, temp. pain)

• Sympathetic pathway (to face)

• Sensation of face (trigeminal nerve)

• Lateral Medullary Syndrome aka Wallenberger Syndrome is the most common brainstem stroke

  • Blood supply from posterior inferior cerebellar artery (PICA)
  • CN 9, 10 problems with trouble swallowing and hoarse voice.
  • Sympathetic fibers cause ipsilateral horner's syndrome - (miosis, pytosis, anhidrosis)
  • Spinothalamic tract - contralateral pain and temperature loss on arm and leg, but no weakness
  • Inferior Vestibular nucleus causes vertigo, nystagmus, nausea, vomiting and hiccups

• Weber Syndrome aka medial midbrain stroke syndrome with:

  • Motor nerves (corticospinal)to body with contralateral weakness of arm and leg
  • The CN 3 has ptosis, double vision, ipsilateral eye down and lateral.

• Locked in syndrome

  • Pons
  • Bilateral motor tracts to body (corticospinal) cause quadriplegia
  • Motor tract to face (corticobulbar) causes facial palsy.
  • CN 6 has a loss of horizontal eye movement

Cerebellar stroke

• Function coordinates and smooths movement

• Blood Supply from:

  • Superior cerebellar artery (from Basilar artery or PCA)
  • AICA (from basilar artery)
  • PICA (from vertebral artery)

• Symptoms

  • Vertigo is common
  • Incoordination of walking (ataxic gait) middle part of cerebellum
  • Incoordination of limb movement (reaching out and touch)- lateral cerebellum ipsilateral side
  • Incoordination of speech with slurred and difficult to understand
  • Impaired eye movements
  • Dysdiadochokinesia which means - unable to perform rapid alternating movements

Case Study

• 55 year old female known diabetic on glibenclamide 5 mg once daily presents with difficulty walking and impaired movements
• Vital signs HR 108/min with no irregularity, no carotid bruit, BP 110/70 mmHg, RR 16/m, Temp 98.7
• What Hx do you want to know?
• What physical exam do you want to do?
• Any lab tests needed give you have access to any lab tests you want?
• Any imaging needed give you have immediate access to any imaging you want?

Evaluation of Stroke

• Need to find how much deficit to they have using the National Institute of Health Stroke Scale (NIHSS)
  • This measures: Level of consciousness, Level of consciousness questions, Level of consciousness commands, Best gaze, Visual, Facial palsy, Motor arm-Left/Right Arm, Motor leg-Left/Right led, Limb ataxia, Sensory, Best language, Dysarthria, and Extinction and inattention.
  • Scored from Zero to 42

Treatment of Ischemic Stroke

• Immediate Treatment Requires Reperfusion Therapy
• Intravenous thrombolysis involves tissue plasminogen activator (tPA)
• tPA must be given within 4.5 hours of symptom onset
• Age > 18
• Normal glucose levels required
• Needs persistent deficit
• BP < 185/110
• No hemorrhage must show on CT/MRI
• Exclusion criteria include
  • ischemic stroke or head trauma in the previous three months
  • prior ICH
  • intraaxial intracranial neoplasm
  • gastrointestinal malignancy
  • gastrointestinal hemorrhage in previous 3 months
  • intracranial or intraspinal surgery in previous 3 months
  • symptoms are suggestive of SAH
    • BP elevated above 185 systolic or 110 diastolic
• No active internal bleeding
• No infective endocarditis
• No known or suspected aortic arch dissection
• Platelet count must be <100,000
• No current anticoagulation with INR > 1.7, PT >15, aPTT> 40
• If use within last 48 hours of direct thrombin inhibitor or direct factor Xa inhibitor with evidence of anticoagulant effect by appropriate assay
• No hemorrhage on CT
• No expensive regions of obvious hypo density consistent with irreversible injury

Mechanical Thrombectomy

• Can happen up to at least to 24 hours after symptom onset

• Limited to large artery occlusion, LAO

• Strong evidence for anterior circulation intervention, limited evidence for posterior circulation LAO.

• Requires CTA or MRA

• Tenecteplase for Ischemic Stroke at 4.5 to 24 is when Thrombectomy is not available

• Ischemic Stroke but not eligible for reperfusion, or reperfusion completed... know what

  • Answer the big three as is it a stroke, where is the injury and the mechanism?
  • Then specific treatment targeted at the cause of the stroke to prevent recurrence

Stroke Evaluation

• Identify Mechanism
• Intracranial arteries, anterior circulation, posterior circulation
  • Extra-cranial arteries
  • Carotids
  • Vertebral artery
  • Aorta
  • Cardiac

StrokeTreatment

• Prevention of Recurrent stroke needed with medication and medical management

  • Antithrombotic therapy depends on the specific mechanism
  • Mono antiplatelet therapy involves ASA alone or clopidogrel alone
  • Dual antiplatelet therapy (DAPT) involves ASA and clopidogrel - followed by mono therapy after 3 months
  • A treatment option is an oral anticoagulant with warfarin or a factor Xa inhibitor
  • BP control goal is under 130/80 as long term goal during medical management
  • If Ischemic stroke, treat 24 hours
  • If tPA eligible use cautiously and lower to 185/110 if needed
  • When tPA not eligible lower if >220/120 with other indication and then cautiously lower by 15% over 24 hours
  • Cholesterol levels addressed, high intensity statin that is atorvastatin at 80mg/day
  • Goal to lower Idl for lower risk, use 70mg/dl - A1C goal is <7

• Lifestyle changes involve

  • A Mediterranean diet
  • Salt intake less than 2.5g/day if additional HTN
  • Exercise with minimum 10 minutes, 4 times per week, with moderate intensity aerobic exercise
  • Smoking cessation
  • Limit or cease alcohol intake, don't stimulate use/IV drug use Then PT/OT/Speech referral is needed

Transient Ischemic Attack

• Transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischemia without acute infarction
• Pathophysiology
  • Essentially the same as a stroke
  • Embolic -occlude long enough to cause brief symptoms and then quickly move
  • Small penetrating artery (Lacunar) commonly stenosis from atherosclerosis or lipohyaninosis
  • Large artery low flow stenosis of large artery

Clinical Manifestations

• Differences happen because of underlying mechanism

  • Embolic
  • Discreet event
  • Less likely to be recurrent and if the have have similar synptoms Symptoms can last for hours
    • Thrombotic strokes are: -Small Vessel (lacunar) are breif and recurrent and has same symptoms (stereotyped)
      • Large artery flow is brief and recircular
      • Anterrior or anterior circulation stereotyped with the posterior which is usually not stereotyped

• Typical TIA- transient, focal, sudden onset, localized to single vascular territory; is likely caused from ischemia from: -Transient monocular blindness which is amaurosis fugax

  • Aphagia or dysarthria -Hemianopsia
  • Hemiparesis and or hemisensory loss

• Atypical includes:

  • Gradual build up of symptoms (more than 5 min)
  • Isolated vision disturbance with “positive phenomena” (flashing lights and spots)
  • Symptoms less than 30 seconds and are identical symptoms for year apart Amnesia and confusion and an incoordination of limbs

• The differential diagnosis includes

  • Seizure (Todd's paralysis)
  • Migraine aura or atypical migraine
  • Passing out (syncope)
  • Cerebral amyloid angiopathy
  • Transient global amnesia
  • MS or other demyelinating disease
  • Peripheral vestibular issue
  • Metabolic/electrolyte disorder
  • Myasthenia gravis
  • Central/periferal neuropathy
  • Subdural hematoma, SAH, ICH

Evaluation of TIA

• Goal is to define identify risk factors, mechanism of ischemia or non-ischemic causes

  • What was the first time and are they still present?
  • Know risk factors of TIA / Stroke?
    • Physical Exam covers:
    • Cardiac exam to check for irregular heartbeats or murmurs/carotid bruits?

• Urgent evaluation is needed and an ECG with CT / MRI within 24 hours - What the symptoms like? - Symptm resoultion?

• Vascular Imaging - Intracranial arteries: -MRA/CTA head - Transcanial doppler ultrasonography - Extra-cranial arteries -MRA/CTA neck (carotids/vertebral artery) or Carotid duplex US -Cardiac - Echocardiogram (TEE vs TTE) -Holter monitor tests

• Immediate Treatment involves determining the likely mechanism and risk to future strokes (ABCD score ) - Identified new or known untreated indication for anticoagulation (a. fib.) start anticoagulation - Otherwise start antiplatelet therapy - High-risk recurrent stroke - add dual antiplatelet therapy (DAPT) - for 21 days followed by mono-therapy Low-risk - Mono-therapy aspirin is enough

• Involves: - Identified mechanism/ risk to future stroke - treat - Risk reduction as would be done for Ischemic Stroke that is: _ Diet and weight reduction_ - Limited no alcconsumption Smoking stopping

Aneurysm

• Approximately 2-3% of population
• There is often a common cause of subarachnoid hemorrhage
• In a 1:1 ratio of female to male up to age 50, after 50, female predominate, up to 2:1

Shape of Aneurysm

• Saccular is “berry” shape
• Fusiform bulges out on all sides

Etiology

• Etiology of an aneurysm is Saccular Stress - Causes breakdown of internal elastic lamina turbulent blood flow vibrations resonate at the same frequency as the vessel wall creating structural

Location

• Branching points from large arteries Ninety percent of aneurysms involve 1 of the 5 :

• Internal carotid artery

• Junction of the anterior cerebral (ACA) artery

• Proximal bifurcation of the middle cerebral artery. Junction posterior cerebral with the basilar Bifurcation internal carotid into anterior with middle cerebral Risk Factors

• Hereditary Syndromes Ehler’s Danlos syndrome and polycystic kidney, moyamoya Familial aneurysm - members with an aneurysm but no hereditary syndrome Hypertension and smoking

• Physical EXAM

• Nothing

• Imaging with CT or MRI, CT angiography, cerebral angiogram

• Unrupted Risk factors: is it small, location, or prior hemorrhagic Treatment

• Nothing can treat smaller than 5mm

• Surgery, clipping or coiling

• Blood pressure and stopSmoking

This lesson covers key considerations in the diagnosis and treatment of ischemic stroke. It emphasizes the importance of rapid assessment and intervention to minimize neurological damage. Topics include differential diagnosis, examination techniques, and immediate treatment options.