Stroke 2010

StrokeStroke

StrokeStroke

Ischaemia is inadequate blood flowIschaemia is inadequate blood flow Stroke occurs when there is ischaemia Stroke occurs when there is ischaemia

to a part of the brain that results in to a part of the brain that results in death of brain cellsdeath of brain cells

StrokeStroke

Functions, such as movement, sensation, Functions, such as movement, sensation, or emotions, that were controlled by the or emotions, that were controlled by the affected area of the brain are lost or affected area of the brain are lost or impairedimpaired

Severity of the loss of function varies Severity of the loss of function varies according to the location and extent of according to the location and extent of the brain involved the brain involved

StrokeStroke

Third on list of top killers of New Zealanders Third on list of top killers of New Zealanders behind heart disease and cancerbehind heart disease and cancer

Approx 1/3 of those who have a stroke die as a Approx 1/3 of those who have a stroke die as a resultresult

Further 1/3 are left with disabilitiesFurther 1/3 are left with disabilities Predicted rise in number of strokes attributed Predicted rise in number of strokes attributed

to population that is growing & ageingto population that is growing & ageing

Risk FactorsRisk Factors

Most effective way to decrease the Most effective way to decrease the burden of stroke is preventionburden of stroke is prevention

Risk factors can be divided into non-Risk factors can be divided into non-modifiable and modifiable risksmodifiable and modifiable risks

Risk FactorsRisk Factors ModifiableModifiable

HypertensionHypertension ObesityObesity Oral contraceptive useOral contraceptive use Physical inactivity Physical inactivity SmokingSmoking

Risk FactorsRisk Factors NonmodifiableNonmodifiable Modifiable Modifiable AgeAge GenderGender RaceRace Heredity Heredity

Asymptomatic Asymptomatic carotid stenosiscarotid stenosis

Diabetes mellitus Diabetes mellitus Heart disease, atrial Heart disease, atrial

fibrillation fibrillation Heavy alcohol Heavy alcohol

consumption consumption Hypercoagulability Hypercoagulability Hyperlipidemia Hyperlipidemia

Etiology and PathophysiologyEtiology and Pathophysiology

Blood is supplied to the brain by 2 Blood is supplied to the brain by 2 major pairs of arteries major pairs of arteries

– Internal carotid arteriesInternal carotid arteries

– Vertebral arteries Vertebral arteries


Carotid arteries branch to supply most Carotid arteries branch to supply most of the of the

– Frontal, parietal, and temporal lobesFrontal, parietal, and temporal lobes

– Basal gangliaBasal ganglia

– Part of the diencephalon Part of the diencephalon ThalamusThalamusHypothalamusHypothalamus


Vertebral arteries join to form the Vertebral arteries join to form the basilar artery, which supply thebasilar artery, which supply the

– Middle and lower temporal lobesMiddle and lower temporal lobes

– Occipital lobesOccipital lobes

– Cerebellum Cerebellum

– BrainstemBrainstem

– Part of the diencephalon Part of the diencephalon


Cerebral arteries Cerebral arteries and the Circle and the Circle

of Willisof Willis


Brain requires a continuous supply of blood Brain requires a continuous supply of blood to provide the oxygen and glucose that to provide the oxygen and glucose that neurons need to function neurons need to function

If blood flow to the brain is totally If blood flow to the brain is totally interruptedinterrupted– Neurologic metabolism is altered in 30 Neurologic metabolism is altered in 30

secondsseconds– Metabolism stops in 2 minutesMetabolism stops in 2 minutes– Cellular death occurs in 5 minutesCellular death occurs in 5 minutes


Brain is normally well protected from Brain is normally well protected from changes in mean systemic arterial blood changes in mean systemic arterial blood pressure by a mechanism known as pressure by a mechanism known as cerebral autoregulation cerebral autoregulation


Cerebral autoregulation involves Cerebral autoregulation involves

– Changes in the diameter of cerebral Changes in the diameter of cerebral blood vessels in response to changes blood vessels in response to changes in pressure so that the blood flow to in pressure so that the blood flow to the brain stays constant the brain stays constant


Factors that affect blood flow to the Factors that affect blood flow to the brainbrain

– Systemic blood pressureSystemic blood pressure

– Cardiac outputCardiac output

– Blood viscosity Blood viscosity


Collateral circulation may develop to Collateral circulation may develop to compensate for a decrease in cerebral compensate for a decrease in cerebral blood flowblood flow

An area of the brain can potentially An area of the brain can potentially receive blood supply from another receive blood supply from another blood vessel if its original blood supply blood vessel if its original blood supply is cut offis cut off


Atherosclerosis is the hardening and Atherosclerosis is the hardening and thickening of arteries and is a major thickening of arteries and is a major cause of strokecause of stroke

It can lead to thrombus formation and It can lead to thrombus formation and contribute to embolicontribute to emboli


Around the core area of ischemia is a Around the core area of ischemia is a border zone of reduced blood flow border zone of reduced blood flow where ischemia is potentially reversible where ischemia is potentially reversible


If adequate blood flow can be restored If adequate blood flow can be restored early (<3 hours) and the ischemic early (<3 hours) and the ischemic cascade can be interrupted, cascade can be interrupted,

– less brain damage and less neurologic less brain damage and less neurologic function lostfunction lost


Transient ischemic attack (TIA) is a Transient ischemic attack (TIA) is a temporary focal loss of neurologic temporary focal loss of neurologic function caused by ischemiafunction caused by ischemia

Most TIAs resolve within 3 hoursMost TIAs resolve within 3 hours


TIAs may be due to microemboli that TIAs may be due to microemboli that temporarily block the blood flowtemporarily block the blood flow

TIAs are a warning sign of progressive TIAs are a warning sign of progressive cerebrovascular diseasecerebrovascular disease

Types of StrokeTypes of Stroke

Strokes are classified based on the Strokes are classified based on the underlying pathophysiologic findings underlying pathophysiologic findings

– IschaemicIschaemic

– HaemorrhagicHaemorrhagic

Ischaemic StrokeIschaemic Stroke

Ischaemic strokes result from Ischaemic strokes result from inadequate blood flow to the brain from inadequate blood flow to the brain from partial or complete occlusion of an partial or complete occlusion of an arteryartery

85% of all strokes are ischaemic strokes 85% of all strokes are ischaemic strokes

Ischemic StrokeIschemic Stroke

Ischaemic strokes can be Ischaemic strokes can be

– Thrombotic Thrombotic

– Embolic Embolic Most patients with ischaemic stroke do Most patients with ischaemic stroke do

not have a decreased level of not have a decreased level of consciousness in the first 24 hoursconsciousness in the first 24 hours

May progress in the first 72 hoursMay progress in the first 72 hours


Thrombotic strokeThrombotic stroke

– Thrombosis occurs in relation to Thrombosis occurs in relation to injury to a blood vessel wall and injury to a blood vessel wall and formation of a blood clotformation of a blood clot

– Result of thrombosis or narrowing of Result of thrombosis or narrowing of the blood vesselthe blood vessel

– Most common cause of strokeMost common cause of stroke




Thrombotic strokeThrombotic stroke

– Two-thirds are associated with Two-thirds are associated with hypertension and diabetes mellitushypertension and diabetes mellitus

– Often preceded by a TIAOften preceded by a TIA


Embolic strokeEmbolic stroke

– Occur when an embolus lodges in and Occur when an embolus lodges in and occludes a cerebral arteryoccludes a cerebral artery

– Results in infarction and oedema of Results in infarction and oedema of the area supplied by the involved the area supplied by the involved vesselvessel

– Second most common cause of strokeSecond most common cause of stroke



– Majority of emboli originate in the Majority of emboli originate in the inside layer of the heart, with plaque inside layer of the heart, with plaque breaking off from the endocardium breaking off from the endocardium and entering the circulation and entering the circulation

– Patient with an embolic stroke Patient with an embolic stroke commonly has a rapid occurrence of commonly has a rapid occurrence of severe clinical symptoms severe clinical symptoms

Embolic StrokeEmbolic Stroke



– Onset of an embolic stroke is usually Onset of an embolic stroke is usually sudden and may or may not be sudden and may or may not be related to activityrelated to activity

– Patient usually remains conscious Patient usually remains conscious although may have a headache although may have a headache



– Often occurs rapidlyOften occurs rapidly

– Recurrence is common unless the Recurrence is common unless the underlying cause is aggressively underlying cause is aggressively treated treated

Hemorrhagic StrokeHemorrhagic Stroke

Account for approximately 15% of all Account for approximately 15% of all strokesstrokes

Result from bleeding into the brain Result from bleeding into the brain tissue itself or into the subarachnoid tissue itself or into the subarachnoid space or ventriclesspace or ventricles


Intracerebral hemorrhageIntracerebral hemorrhage

– Bleeding within the brain caused by a Bleeding within the brain caused by a rupture of a vesselrupture of a vessel

– Hypertension is the most important Hypertension is the most important causecause

– Haemorrhage commonly occurs Haemorrhage commonly occurs during periods of activityduring periods of activity

Intracerebral HaemorrhageIntracerebral Haemorrhage


Intracerebral haemorrhageIntracerebral haemorrhage

– Often a sudden onset of symptoms, Often a sudden onset of symptoms, with progression over minutes to with progression over minutes to hours because of ongoing bleedinghours because of ongoing bleeding


Intracerebral haemorrhageIntracerebral haemorrhage

– Manifestations include neurologic Manifestations include neurologic deficits, headache, nausea, vomiting, deficits, headache, nausea, vomiting, decreased levels of consciousness, and decreased levels of consciousness, and hypertension hypertension


Subarachnoid haemorrhageSubarachnoid haemorrhage

– Occurs when there is intracranial Occurs when there is intracranial bleeding into cerebrospinal fluid-bleeding into cerebrospinal fluid-filled space between the arachnoid filled space between the arachnoid and pia materand pia mater

– Commonly caused by rupture of a Commonly caused by rupture of a cerebral aneurysm cerebral aneurysm

Subarachnoid StrokeSubarachnoid Stroke

Stroke – Part BStroke – Part B

Clinical ManifestationsClinical Manifestations

Affects many body functionsAffects many body functionsMotor activityMotor activityEliminationEliminationIntellectual functionIntellectual functionSpatial-perceptual alterationsSpatial-perceptual alterationsPersonalityPersonalityAffect Affect Sensation Sensation Communication Communication

Clinical ManifestationsClinical Manifestations

Brain attack Brain attack – Term increasingly being used to Term increasingly being used to

describe stroke and communicate describe stroke and communicate urgency of recognizing stroke urgency of recognizing stroke symptoms and treating their onset as symptoms and treating their onset as a medical emergencya medical emergency

Clinical ManifestationsClinical ManifestationsMotor FunctionMotor Function

Most obvious effect of strokeMost obvious effect of stroke Include impairment ofInclude impairment of

– Mobility Mobility

– Respiratory functionRespiratory function

– Swallowing and speechSwallowing and speech

– Gag reflexGag reflex

– Self-care abilities Self-care abilities


Characteristic motor deficitsCharacteristic motor deficits

– Loss of skilled voluntary movementLoss of skilled voluntary movement

– Impairment of integration of Impairment of integration of movementsmovements

– Alterations in muscle toneAlterations in muscle tone

– Alterations in reflexesAlterations in reflexes


An initial period of flaccidity may last An initial period of flaccidity may last from days to several weeks and is from days to several weeks and is related to nerve damagerelated to nerve damage

Spasticity of the muscles follows the Spasticity of the muscles follows the flaccid stage and is related to flaccid stage and is related to interruption of upper motor neuron interruption of upper motor neuron influence influence

Clinical ManifestationsClinical ManifestationsCommunicationCommunication

Patient may experience aphasia when a Patient may experience aphasia when a stroke damages the dominant stroke damages the dominant hemisphere of the brainhemisphere of the brain

– Aphasia is a total loss of Aphasia is a total loss of comprehension and use of languagecomprehension and use of language


Dysphasia refers to difficulty related to Dysphasia refers to difficulty related to the comprehension or use of language the comprehension or use of language and is due to partial disruption or lossand is due to partial disruption or loss

Dysphasia can be classified as nonfluent Dysphasia can be classified as nonfluent or fluent or fluent


Many patients also experience Many patients also experience dysarthria dysarthria

– Disturbance in the muscular control Disturbance in the muscular control of speechof speech

Impairments may involve Impairments may involve pronunciation, articulation, and pronunciation, articulation, and phonation phonation


Dysarthria does not affect the meaning Dysarthria does not affect the meaning of communication or the comprehension of communication or the comprehension of languageof language

It does affect the mechanics of speechIt does affect the mechanics of speech

Clinical ManifestationsClinical ManifestationsAffectAffect

Patients who suffer a stroke may have Patients who suffer a stroke may have difficulty controlling their emotionsdifficulty controlling their emotions

Emotional responses may be Emotional responses may be exaggerated or unpredictable exaggerated or unpredictable

Clinical ManifestationsClinical ManifestationsAffectAffect

Depression and feelings associated with Depression and feelings associated with changes in body image and loss of changes in body image and loss of function can make this worsefunction can make this worse

Patients may also be frustrated by Patients may also be frustrated by mobility and communication problemsmobility and communication problems

Clinical ManifestationsClinical ManifestationsIntellectual FunctionIntellectual Function

Both memory and judgment may be Both memory and judgment may be impaired as a result of strokeimpaired as a result of stroke

A left-brain stroke is more likely to A left-brain stroke is more likely to result in memory problems related to result in memory problems related to languagelanguage

Clinical ManifestationsClinical ManifestationsSpatial-Perceptual AlterationsSpatial-Perceptual Alterations

Stroke on the right side of the brain is Stroke on the right side of the brain is more likely to cause problems in spatial-more likely to cause problems in spatial-perceptual orientationperceptual orientation

However, this may occur with left-However, this may occur with left-brain strokebrain stroke

Spatial & Perceptual Deficits Spatial & Perceptual Deficits in strokein stroke

Food on the left Food on the left side is not seen side is not seen and thus is and thus is ignoredignored

Clinical ManifestationsClinical ManifestationsSpatial-Perceptual AlterationsSpatial-Perceptual Alterations

Spatial-perceptual problems may be divided Spatial-perceptual problems may be divided into 4 categoriesinto 4 categories

1.1. Incorrect perception of self and illnessIncorrect perception of self and illness

2.2. Erroneous perception of self in spaceErroneous perception of self in space

3.3. Inability to recognize an object by Inability to recognize an object by sight, touch, or hearing (agnosia)sight, touch, or hearing (agnosia)

4.4. Inability to carry out learned Inability to carry out learned sequential movements on command sequential movements on command (apraxia)(apraxia)

Clinical ManifestationsClinical ManifestationsEliminationElimination

Most problems with urinary and bowel Most problems with urinary and bowel elimination occur initially and are elimination occur initially and are temporarytemporary

When a stroke affects one hemisphere When a stroke affects one hemisphere of the brain, the prognosis for normal of the brain, the prognosis for normal bladder function is excellent bladder function is excellent

Clinical ManifestationsClinical ManifestationsRight and Left Brain DamageRight and Left Brain Damage

Aphasia Aphasia http://www.strokecenter.org/pat/aphasia.html

Health & Medicine

Stroke 2010