Stroke 101 – Overview of Anatomy and Pathology

Robin Raju, DO

Medical Director

St. Luke’s Acute Rehabilitation Center

Objectives

Basic classification of stroke events Common types of ischemic stroke Ischemic stroke mechanisms Locate the damage from a stroke based on

the patient’s presentation

Differential diagnosis

Acute interventions

Cerebrovascular Accident

Sudden or rapid onset of focal neurological deficit or symptoms

TIA not only on the basis of duration but also on the absence of acute infarct on brain imaging

Types of Stroke

Stroke

Atheroscleroticvascular

disease 20%

HypotensionArtery-artery

emboli

Penetrating artery disease(lacunes) 25%

Cardiogenic embolism 20%

Cryptogenic stroke 30%

Unusual causes 5%

Primary Hemorrhage

15%

Ischemic Stroke 85%

Thrombotic vs Embolic

Anatomy

Basal Ganglia

Caudate nucleus

Internal capsule

Putamen

Globus Pallidus

Amygdaloid complex

Corpus Callosum

Circulation

Right Hemisphere Stroke

Both cortical and subcortical strokes: Lt hemiparesis

Lt sensory loss

Cortical strokes also include: Lt spatial neglect

Lt homonymous hemianopsia

Impaired Lt conjugate gaze

Left Hemisphere Stroke

Both cortical and subcortical strokes: Rt hemiparesis

Rt sensory loss

Cortical strokes also include: Aphasia

Rt spatial neglect

Rt homonymous hemianopsia

Impaired Rt conjugate gaze

Deep Subcortical Strokes

Hemiparesis (pure motor) or sensory loss (pure sensory)

Dysarthria and clumsy-hand with dysarthria

Ataxic hemiparesis

No cognitive, visual or language abnormalities

Brain Stem - The “D’s”

Motor or sensory loss in 4 limbs Crossed signs (same side of face and opposite on

body) Dysconjugate gaze Dizziness/Disequilibrium

Nystagmus Ataxia

Dysarthria Dysphagia Deafness (Change in hearing)

Differential Diagnosis

Unrecognized seizures

Confused states, psychiatric disorders

Syncope

Toxic/metabolic derangements

Tumors, abscess and subdural hematoma

Migraine

Meningitis, encephalitis

Clinical EvaluationHistory

Past history TIA/Stroke

Time of onset

Activity at onset

Temporal progression

Accompanying signs

Risk factors for vascular disease

Non atherosclerotic conditions

Clinical EvaluationPhysical exam

ABC’s

Signs of trauma

Neck stiffness and bruits

Cardiac auscultation

Abdomen - aneurysm, bruits

Peripheral vascular exam

Clinical Evaluation-Initial studies

CT acutely/MRI in selected Pts

EKGGlucose/ElectrolytesBUN/CrCBC/platelet countPT/INRPTTLFT

ToxicologyBlood AlcoholPregnancy testO2 saturation/ABGCXRLPEEG

Clinical Evaluation-Later studies

MRI contrast, MRA/CTA

Carotid duplex ultrasound

Angiography

Echocardiogram (TTE/TEE)

EEG

Cardiac monitoring

Labs: lipid panel, RPR, ESR/C-reactive protein, ANA, anticardiolipin antibodies, homocysteine, fibrinogen

Interventions

Ischemic core - irreversibly damaged brain tissue

Ischemic penumbra – an area of under perfused but still viable tissue

Interventions

IV administered rt-PA – 3 hour window

IA administered rt-PAEndovascular procedures Secondary stroke preventions

NINDS trial - Effect of IV t-PA at 0-3 Hours

Outcome Likelihood with Placebo Likelihood with t-PA

Good functional outcome (mRS score 0-1) at 3 months

26.5% 42.5% (NNT 7)

Symptomatic intracranial hemorrhage (NINDS definition) at 36 hours

0.6% 6.4% (NNH 17)

Mortality 21% 17% (Not significant)

IV t-PA at >3 hours

t-PA given 3-4.5 hours after stroke onset

Increases risk of symptomatic intracranial hemorrhage and risk of fatal intracranial hemorrhage within 7 days (level 1 evidence)

Might increase 90-day mortality (level 2 evidence) while effect on improving functional outcomes is uncertain and inconsistent across trials

Intra-arterial t-PA

Considered beneficial for selected patients with major ischemic stroke < 6 hours old due to proximal cerebral artery occlusion and not eligible for IV t-PA (level 2 evidence)

May reduce disability but increase risk of intracranial hemorrhage (level 2 evidence)

References:

Ropper, Allan H., Martin A. Samuels, Raymond D. Adams, and Maurice Victor. Adams and Victor's Principles of Neurology. New York: McGraw-Hill Medical, 2005. Print.

"Anatomy of Brain - Netter Medical Images." Anatomy of Brain - Netter Medical Images. Web. 26 Jan. 2015.

"Acute Management - Stroke." www.dynamed.com. Web. 26 Jan. 2015.

Dachs, Robert J., John H. Burton, and Jeremy Joslin. "A User's Guide to the NINDS Rt-PA Stroke Trial Database." PLoS Medicine 5.5 (2008): E113. Web.

Bhidayasiri, Roongroj, Michael F. Waters, and Christopher C. Giza. Neurological Differential Diagnosis: A Prioritized Approach. Malden, MA: Blackwell, 2005. Print.