stroke ppt july 2006
DESCRIPTION
overview of strokeTRANSCRIPT
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
Cerebral arteries Cerebral arteries and the Circle and the Circle
of Willisof Willis
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Etiology and PathophysiologyEtiology and Pathophysiology
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
Ischaemic StrokeIschaemic Stroke
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
Ischaemic StrokeIschaemic Stroke
Ischaemic StrokeIschaemic Stroke
Ischaemic StrokeIschaemic 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
Ischaemic StrokeIschaemic Stroke
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
Ischaemic StrokeIschaemic Stroke
Embolic strokeEmbolic 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
Ischaemic StrokeIschaemic Stroke
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
Ischaemic StrokeIschaemic Stroke
Embolic strokeEmbolic stroke
– 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
Hemorrhagic StrokeHemorrhagic Stroke
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
Hemorrhagic StrokeHemorrhagic Stroke
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
Hemorrhagic StrokeHemorrhagic Stroke
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
Hemorrhagic StrokeHemorrhagic Stroke
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
Clinical ManifestationsClinical ManifestationsMotor FunctionMotor Function
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
Clinical ManifestationsClinical ManifestationsMotor FunctionMotor Function
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
Clinical ManifestationsClinical ManifestationsCommunicationCommunication
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
Clinical ManifestationsClinical ManifestationsCommunicationCommunication
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
Clinical ManifestationsClinical ManifestationsCommunicationCommunication
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/aphasihttp://www.strokecenter.org/pat/aphasia.htmla.html