Neurology: STROKE

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Stroke

• Condition characterized by rapidly developing signs and symptoms of a focal brain legion with symptoms lasting for more than 24 hours or leading to death no apparent reason

• Sudden neurologic syndrome, cerebrovascular disease – pathologic process of blood vessels– Occlusion of lumen by embolus/thrombus– Dissection – Permeability of blood vessel wall

Primary disorder

• Atherosclerosis• Hypertensive

Epidemiology

• 2nd most common cause of death around the world, next to heart disease

• Out of 2 million, 2% will have a stroke• If you will have stroke, 30% will die, 30%

permanently disabled, 30% recover• 10,000/1 mil (Philippines) = 1%• Cerebrovascular disease (stroke) = highest

percentage of disability computed in life years

Morbidity and mortality

• 700,000 strokes per year in US• 22% men and 25% of women, higher among

65 years old• 1st leading cause of long-term disability• 2.7 million related stroke death in Asia,

leading cause of death in China– Intracranial atherosclerosis, common in Asians

31%

Risk factors (non-modifiable)

• Age: Elderly• Gender : Males more susceptible• Genetic predisposition• Race/ethnicity: Non white groups have greater

disk• Prior stroke or MI: Higher risk• Existing heart disease: increase risk for stroke

Modifiable• Lifestyle

– Smoking– Low physical exercise– Obesity– Alcohol consumption– Dietary restrictions

• Pharmacotherapy– Hypertension– Arterial disease– Heart disease– Thrombotic phenomenon or embolic – Diabetes mellitus

Diagnosis

• Clinical• Based on history• Characteristic signs

Subtypes

• Ischemic– Thrombotic– Embolic– Hyperfusion

• Hemorrhagic – Intracranial haemorrhage – Subarachnoid hemorrhagic

Mechanism

• Borderzone – 5%• Lacunar – 20%• Cryptogenic/rare cases – 20%• Artery to artery – 20%• Aortic arch -20%

Stroke sub classifications according to clinical presentation

• TACI – total anterior circulation infarct– Higher dysfunction– Homonymous hemianopsia– Motor/sensory deficit • 2/3 face arm/arm/leg

PACI – partial anterior circulation (1/3 to ¼ of the brain)

• 2 of 3 of TACI• Higher dysfunction alone• Limited motor/sensory deficit

LACI - lacunar anterior circulation infarct

• Pure motor stroke (2/3 parts)• Pure sensory• Sensorimotor• Ataxic hemiparesis– New dysphagis– New visuosptial problem– Proprioceptie sensory loss only– Vertebrobasilar features

POCI – posterior

• Crossed motor sensory deficit• Bilateral motor or sensory deficit• Conjugate eye movements problems• Cerebellar dysfunction• Isolated homonymous hemianopsia

The brain

15% of cardiac output20% of all O225% of all glucose 2-3% body weight

*50ml/100gms/min*500mlof O2/min*75-100ml of glucose/min

• Oligemia – diminished blood flow(increased O2 extraction

• Mild ischemia – increase in glycolysis, below 20cc – threshold for electrical failure

• 10-20 cc per 100 grams per brain tissue per min = PENUMBRA – moderate ischemia

• Severe ischemia – anoxic depolarization

If perfusion of the cerebrum is suspended or critically reduced there are limited capacities for compensation and minimal energy reserves

*auto regulation

Vascular anatomy

• Anterior circulation – from carotid system (80% supply of brain)

• Posterior circulation – from vertebral system (20% supply of brain)

Atherosclerosis and Thrombus foundation

• Main pathology that can bring about stroke • Site of endothelial injury• Thrombus formation = ischemia• Formation of a plaque (atherosclerotic)• Atherosclerotic develops in time

Thrombus formation and embolism

• Leads to infract in brain• Thrombus = impedes laminar flow of blood,

time characteristic• Embolism = small piece of clot, thrown off that

can block, smaller than thrombus

Extant and size of ischemia

• Rate of occlusion – paulit-ulit ba?• Adequacy of collateral circulation • Resistance of brain structures to ischemia –

dependent on function of cerebral autoregulation (ability of the blood vessel to respond, elasticity of blood vessels)

Sites of atherosclerosis

• Common area where it forms the junction • Junction between MCA and ACA• Mas malakas ang laminar flow sa junctions =

increased pressure

Types of stroke

• Ischemic stroke (infarct)• Hemorrhagic stroke = intracerebral

haemorrhages, compression, herniation and shifting of structure

Ischemic stroke

• 85% of stroke• Thrombotic or embolic• One month mortality: 15%

Middle cerebral artery

• Most common intracranially involved in ischemic stroke

• Supply almost all parts of the convex surface of brain

• Supply deep tissue: basal ganglia, putamen, parts of globus pallidus...

• Usually hypodense lesion – left MCA stroke• Contralateral paresis – pyramidal decussation,

unilateral lesion

Left hemisphere = dominant

• Right motor deficits– Face– Upper and lower extremitiesRight sensory loss

All modalitiesDecreased stereognosisAgraphesthesia

Language deficitsRight homonymous hemianopsiaAgraphia, acalculia, apraxia of left limbs

Right hemisphere

• Left hemiparesis• Left weakness of upper and lower extremities• Left hemineglect• Asomatognosia• Flat affect• Loss of prosody of speech

Anterior cerebral artery

• Supply medial and basal aspects of cerebral hemisphere

• Extends to anterior two thirds• Caudate nucleus, parts if internal capsule,

putamen and hypothalamus

ACA stroke

• Weakness of leg• +/- proximal muscle weakness in upper ex• Affect frontal lobe: impaired judgement and

insight, change in affect• Presence of primitive grasp and suck reflex

Vertebrobasilar system

• Supplies:– Brainstem– Cerebellum– Thalamus– Visual occipital cortex

Vertebrobasilar

• Level of consciousness– Ranges from alert to coma– No cognitive impairments– Confusion or agitation uncommon

• Motor impairments– Contralateral paresis of upper and lower ex– Quadriparesis – buong basilar artery involved– Crossed paresis– Dysarthria, hoarseness, dysphagia, ipisilateral ataxia, gait

or truncal instability (cerebellar vermis involvement)

• Sensory impairments• Abnormalities of extraocular movement• Vertigo, nasuea, vomitting• Horner’s syndrome

Hemorrhagic stroke

• 15% of all total strokes• Intracerebaral > subarachnoid haemorrhage• Occur during stress or exertion• Focal deficits rapidly evolve• Confusion, coma, immediate death

Intracerebral• Classic: sudden onset• Vomiting, elevated BP• Focal neurologic deficits that progress over minutes• Larger the deficits, the poorer the prognosis will be• Hypertensive damage to small penetrating vessels and has the

same vascular distribution as lipophyalinosis• Charcot and Bouchard – mcircoaneurysm which ruptured,

causing ICH• Other causes: trauma, ruptured aneurysm, AV malformation,

anticoagulant intake, thrombolytic agents, cerebrovascular amyloidosis, bleeding disorders (leukemia)

ICH

• Most common site: putamen and adjacebt structures

• Rupture of small penetrating branches of thalamus, pons, cerbellum

Subarachnoid hemorrhage

• Rupture of an aneurysm (usually located in the circle of Willis)

Subarachnoid hemorrhage• Headache– Severe– Sudden or cataclysmic onset– Described as worst headache of life

• Transient loss of consciousness, seizure, syncope, prolonged unresponsiveness, confusion, agitation

• Nausea and vomitting• Photophobia and phonophobia• Hypertension and abnormal vital signs• Nuchal rigidity• Retinal haemorrhage

• May be secondary to ruptured aneurysm or arteriovenous malformation

• 3 major risks affect subsequent events– Rebleeding– Vasoconstriction (delayed ischemic deficit)– Hydrocephalus (blood impedes normal flow)

Management goals

• Goals immediate diagnosis and evaluation:– Determine symptoms due to stroke– Advisability for acute treatment with thrombolytic

therapy

Management goals

• History of physical examination– Note vital signs– Cardiac examination– Check for Carotid bruit

• Validated scoring systems e.g. NIHSS to determine stroke severity

• Immediate diagnostic studies– Cranial CT scan– ECG– Bloof glucose level– Serum electrolyte– Renal function test– CBC including platelet count

General supportive care

• ABC – airway, breathing, circulation• Control of fever• Cardiac rhythm• Hypoglycemia/hyperglycemia

General supportive care

• Hypertension– No clinically proven benefit for lowwering BP

among patients with acute ischemic stroke– Antihypertensive agents should be withheld

unless• DBP>120 or SBP>220• Hypertensive encephalopathy• Aortic dissection• Acute renal failure• Acute pulmonary edema• Acute myocardial infarction

Neuroimaging

• Non-contrast enhanced CT scan of the brain– Early signs of infarction• Hyperdense MCA sign• Loss of gray-white differentiation in the cortical ribbon

(particularly the lateral margins of the insula) or the lentiform nuclues • Sulcal effacement

Neuroimaging

• Multimodal MRI– DWI (diffusion weighted image)• Perfusion-diffusion mismatch (PWI: Perfusion weighted

image)– Potential difficulty in reliably identifying acute

intracranial hemorrhage - GRE

Interventions

• Primary prevention• Acute phase • Secondary prevention

Treatment options – Acute phase

• Stroke units• Thrombolysis• Neuroprotection• Aspirin and heparin• Surgery and intra-cerebral hemorrhage• Early secondary prevention

• Risk factor • Neuroprotectants• Thrombolytics• Stroke unit Stroke Event • Hematoma evacuation 3 hours • Revascularization Hospital • Recanalization

Treatment options – Secondary prevention

• Antiplatelet (thrombotic) and anticoagulant (embolic) therapy

• Antihypertensive treatment post stroke• Statin therapy• Carotid artery disease

Intervention Outcome OR (95% C.I) NNTNumber needed to

treat

Stroke unit

Death

Death or institutionalization

0.81 (0.68-0.96)

0.75 (0.65-0.87)

21

14

Death or dependency 0.71 (0.60 -0.84) 15

ASA

Thrombolysis

Death or dependency

Early death (2w)

Early ICH (2w)

Death

0.95 (0.91-0.99)

1.99 (1.56-2.55)

3.6 (2.7-4.8)

1.36 (1.1-1.6)

83

-

-

-Death dependency 0.75 (0.6-0.9) 15

Storokeunit team

1. Medical doctor2. Pyshiotherapist3. Nurses4. OT5. Social worker6. Speech pathologist7. Home care case manager8. Nutritionist

Thrombolysis

• IV Intrevnous rtPA– The only FDA approved therapy for treatment of

patients with acute ischemic stroke• IA rtPA– Experimental

• Established as a treatment in acute ischemic stroke patients within 3 hours of stroke onset

Secondary stroke prevention

• Aspirin recommended 50 – 325 mg/day • Clopidogrel - Plavix• Ticlid – best selling• Aggrenox

NNT

33

121

40

Neuroprotection

• No present clinical trials that demonstrated benefit for neuroprotective agents

• Citicoline• Cerebrolycine?• Magnesium sulfate

• Clipping – gold standard for cerebral aneurysm, craniotomy • Coiling – less invasive, angiogram procedure (endovascular

treatment)– Now preferred treatment for aneurysm– 7.4% absolute risk reduction in combined death and instability

compared to clipping– Durability of coil still unknown due to lack of long term followup– Treatment choice for basillar artery aneurysm– Commonly used to treat post SAH vasospasm

Hypertensive hemorrhage• Recombinant activated facotr VIIa (rFVIIa)• Hemostatic agent approved for hemophilia (Novo Seven)• 3 hour time window• Decreased enlargement of the hemotoma• Improve survival and favorable clinical outcomes

• Potential thrombotic complications (arterial thrombolytic events) – 7%

• FDA approval pending due to this safety issue