Approach to a patient with stroke

Ashwin HaridasAsem Ali Ashraf

Adam EAH Adam

DefinitionsStroke

Clinical syndrome of rapid onset of focal deficits of brain function lasting more than 24 hours or leading to death

Transient Ischemic attack (TIA)Clinical syndrome of rapid onset of focal

deficits of brain function which resolves within 24 hours

DefinitionsProgressive Stroke

A stroke in which the focal neurological deficits worsen with time

Also called stroke in evolution

Completed StrokeA stroke in which the focal neurological deficits

persist and do not worsen with time

EpidemiologyThird most common cause of death after

cancer and ischeamic heart diseaseMost common cause of severe physical

disabilityPrevalence of stroke in India is about 1.54

per 1000Death rate is about 0.6 per 1000Incidence and prevalence of stroke is on the

rise due to increasing adoption of unhealthy lifestyle & an increasing life expectancy

Stroke Risk FactorsFixed

AgeGender

(Male>Female)Race (Afro-

Caribbean>Asian>European)

HeredityPrevious vascular

event eg. MI, peripheral embolism

High fibinogen

ModifiableHypertensionHeart disease

(Atrial fibrillation, endocarditis)

Diabetes mellitusHyperlipidaemiaSmokingExcess alcohol

consumptionOral contraceptives

Types of StrokeIschemicHemorrhagic

Anterior Circulation

Posterior Circulation

Middle Cerebral Artery

Anterior Cerebral Artery

Posterior Cerebral Artery

Ischemic Stroke80% of strokesArterial occlusion of an intracranial vessel

leads to hypoperfusion of the brain region it supplies

Etiology of ischemic strokeThrombotic

Lacunar strokeLarge vessel

thrombosisHypercoagulable

disorders

EmbolicArtery to artery

Carotid bifurcation Aortic arch

Cardioembolic Atrial fibrillation Myocardial infarction Mural thrombus Bacterial endocarditis Mitral stenosis Paradoxical embolus

Thrombotic Stroke

Atherosclerosis is the most common pathology leading to thrombotic occlusion of blood vessels

Hypercoagulable disorders – uncommon causeAntiphospholipid syndromeSickle cell anemiaPolycythemia veraHomocysteinemia

Vasculitis: PAN, Wegener’s granulomatosis, giant cell arteritis

Lacunar strokeAccounts for 20% of all strokesResults from occlusion of small deep

penetrating arteries of the brainPathology: lipohyalinosis & microatheromaThrombosis leads to small infarcts known as

lacunesClinically manifested as lacunar syndromes

Thrombotic Stroke

Embolic StrokeCardioembolic stroke

Embolus from the heart gets lodged in intracranial vessels

MCA most commonly affectedAtrial fibrillation is the most common causeOthers: MI, prosthetic valves, rheumatic heart disease

Artery to artery embolismThrombus formed on atherosclerotic plaques gets

embolized to intracranial vesselsCarotid bifurcation atherosclerosis is the most comon

sourceOthers: aortic arch, vertebral arteries etc.

Etiology of ischemic stroke

Blood supply to the brain is autoregulatedBlood flow

If zero leads to death of brain tissue within 4-10min

<16-18ml/100g tissue/min infarction within an hour

Ischemia leads to development of an ischemic core and an ischemic penumbra

Pathophysiology of Ischemic Stroke

Ischemic Penumbra

Tissue surrounding the core region of infarction which is ischemic but reversibly dysfunctional

Maintained by collateralsCan be salvaged if reperfused in

timePrimary goal of revascuralization

therapies

ATP depletion

Hypoperfusion

Failure of Na+/K+ ATPase membrane ionic pump

Calcium entryGlutamate release

Activation of lipid peroxidases, proteases & NO synthase

Destruction of intracellular organelles, cell membrane & release of free radicals

Free fatty acid release

Activation of pro-coagulant pathways

Liquefactive necrosis

Thrombus/embolus

Membrane depolarization & cytotoxic cellular edema

Hemorrhagic Stroke

Two typesIntracerebral

hemorrhage(ICH)Subarachnoid

hemorrhage(SAH)Higher mortality

rates when compared to ischemic stroke

Intracerebral Hemorrhage• Result of chronic hypertension• Small arteries are damaged due to

hypertension• In advanced stages vessel wall is disrupted

and leads to leakage• Other causes: amyloid angiopathy,

anticoagulant therapy, cavernous hemangioma, cocaine, amphetamines

Subarachnoid HemorrhageMost common cause is rupture of saccular or

Berry aneurysmsOther causes include arteriovenous

malformations, angiomas, mycotic aneurysmal rupture etc.

Associated with extremely severe headache

Pathophysiology Of Hemorhagic Stroke

Explosive entry of blood into the brain parenchyma structurally disrupts neurons

White matter fibre tracts are splitImmediate cessation of neuronal functionExpanding hemorrhage can act as a mass

lesion and cause further progression of neurological deficits

Large hemorrhages can cause transtentorial coning and rapid death