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| {{Infobox_Disease | | __NOTOC__ |
| | Name = Stroke
| | {| class="infobox" style="float:right;" |
| | Image = MCA-Stroke-Brain-Human-2.JPG
| | |- |
| | Caption = A slice of brain from the autopsy of a person who suffered an acute MCA stroke
| | | [[File:Siren.gif|30px|link=Stroke resident survival guide]]|| <br> || <br> |
| | DiseasesDB = 2247
| | | [[Stroke resident survival guide|'''Resident'''<br>'''Survival'''<br>'''Guide''']] |
| | ICD10 = {{ICD10|I|61||i|60}}-{{ICD10|I|64||i|60}}
| | |} |
| | ICD9 = {{ICD9|434}}
| | {{Ischemic stroke}} |
| | ICDO =
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| | OMIM = 601367
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| | MedlinePlus = 000726
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| | eMedicineSubj = neuro
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| | eMedicineTopic = 9
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| | eMedicine_mult = {{eMedicine2|emerg|558}} {{eMedicine2|emerg|557}} {{eMedicine2|pmr|187}}
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| | MeshID = D020521
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| }}
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| {{SI}} | |
| {{WikiDoc Cardiology Network Infobox}}
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| {{CMG}}
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| {{Editor Help}} | | {{CMG}} {{AE}}{{AAA}} |
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| '''Stroke''' or '''[[cerebrovascular accident]] ([[CVA]])''' is the rapidly developing loss of brain functions due to a disturbance in the blood vessels supplying blood to the brain. This can be due to [[ischemia]] (lack of blood supply) caused by [[thrombosis]] or [[embolism]], or due to a [[hemorrhage]].<ref>{{cite book |author=Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Robbins, Stanley L.; Abbas, Abul K. |title=Robbins and Cotran pathologic basis of disease |publisher=Elsevier Saunders |location=St. Louis, Mo |year=2005 |pages= |isbn=0-7216-0187-1}}</ref> In medicine, a stroke, fit, or faint is sometimes referred to as an '''ictus [cerebri]''', from the Latin ''icere'' ("to strike"), especially prior to a definitive diagnosis.
| | {{SK}} Cerebrovascular accident; cerebrovascular event; CVA; cerebral emboli; brain attack; ischemic stroke |
| | ==[[Stroke overview|Overview]]== |
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| Stroke is a [[medical emergency]] and can cause permanent neurological damage, complications and death if not promptly diagnosed and treated. It is the third leading cause of [[death]] and the leading cause of adult disability in the United States and Europe. It is predicted that stroke will soon become the leading cause of death worldwide.<ref name="feigin2005">{{cite journal |author=Feigin VL |title=Stroke epidemiology in the developing world |journal=Lancet |volume=365 |issue=9478 |pages=2160–1 |year=2005 |pmid=15978910 |doi=10.1016/S0140-6736(05)66755-4}}</ref> Risk factors for stroke include [[Old age|advanced age]], [[hypertension]] (high blood pressure), previous stroke or [[transient ischemic attack]] (TIA), [[diabetes mellitus|diabetes]], [[hypercholesterolemia|high cholesterol]], [[cigarette smoking]], [[atrial fibrillation]], [[migraine]] with aura, and [[thrombophilia]] (a tendency to [[thrombosis]]). Blood pressure is the most important modifiable [[risk factor]] of stroke.
| | ==[[Ischemic stroke historical perspective|Historical Perspective]]== |
| | ==[[Ischemic stroke classification|Classification]]== |
| | ==[[Ischemic stroke pathophysiology|Pathophysiology]]== |
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| The traditional definition of stroke, devised by the [[World Health Organisation]] in the 1970s,<ref>{{cite book |author=World Health Organisation |title=Cerebrovascular Disorders (Offset Publications) |publisher=[[World Health Organization]] |location=Geneva |year= |pages= |isbn=9241700432 |oclc= |doi=}}</ref> is a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours". This definition was supposed to reflect the reversibility of tissue damage and was devised for the purpose, with the time frame of 24 hours being chosen arbitrarily. It divides stroke from TIA, which is a related syndrome of stroke symptoms that resolve completely within 24 hours. With the availability of treatments that, when given early, can reduce stroke severity, many now prefer alternative concepts, such as '''brain attack''' and '''acute ischemic cerebrovascular syndrome''' (modeled after [[myocardial infarction|heart attack]] and [[acute coronary syndrome]] respectively), that reflect the urgency of stroke symptoms and the need to act swiftly.<ref>{{cite journal | last=Kidwell | first=C | coauthors=Warach S |title=Acute ischemic cerebrovascular syndrome: diagnostic criteria |journal=Stroke |volume=34 |issue=12 |pages=2995–8 |year=2003 |pmid=14605325 |doi=10.1161/01.STR.0000098902.69855.A9| url=http://stroke.ahajournals.org/cgi/content/full/34/12/2995}}</ref>
| | ==[[Stroke causes|Causes]]== |
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| Treatment of stroke is occasionally with [[thrombolysis]] ("clot buster"), but usually with supportive care ([[physiotherapy]] and [[occupational therapy]]) and secondary prevention with [[antiplatelet drug]]s ([[aspirin]] and often [[dipyridamole]]), blood pressure control, [[statin]]s and [[Anticoagulant|anticoagulation]] (in selected patients).<ref>{{cite journal |author=Hackam DG, Spence JD |title=Combining multiple approaches for the secondary prevention of vascular events after stroke: a quantitative modeling study |journal=Stroke |volume=38 |issue=6 |pages=1881–5 |year=2007 |pmid=17431209 |doi=10.1161/STROKEAHA.106.475525}}</ref>
| | ==[[Ischemic stroke differential diagnosis|Differentiating Stroke from other Diseases]]== |
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| ==Classification== | | ==[[Ischemic stroke epidemiology and demographics|Epidemiology and Demographics]]== |
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| Strokes can be classified into two major categories: ischemic and hemorrhagic. [[Ischemia]] is due to interruption of the blood supply, while [[hemorrhage]] is due to rupture of a [[blood vessel]] or an abnormal vascular structure. 80% of strokes are due to ischemia; the remainder are due to hemorrhage.
| | ==[[Ischemic stroke risk factors|Risk Factors]]== |
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| ===Ischemic stroke=== | | ==[[Stroke natural history|Natural History, Complications and Prognosis]]== |
| In an ischemic stroke, blood supply to part of the brain is decreased, leading to dysfunction and [[necrosis]] of the brain tissue in that area. There are four reasons why this might happen: thrombosis (obstruction of a blood vessel by a [[blood clot]] forming locally), embolism (idem due to a embolus from elsewhere in the body, see below), systemic hypoperfusion (general decrease in blood supply, e.g. in [[Shock (medical)|shock]]) and [[cerebral venous sinus thrombosis|venous thrombosis]]. Stroke without an obvious explanation is termed "cryptogenic" (of unknown origin).
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| ;Thrombotic stroke
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| In thrombotic stroke, a thrombus (blood clot) usually forms around [[atherosclerosis|atherosclerotic]] plaques. Since blockage of the artery is gradual, onset of symptomatic thrombotic strokes is slower. A thrombus itself (even if non-occluding) can lead to an embolic stroke (see below) if the thrombus breaks off, at which point it is called an "embolus". Thrombotic stroke can be divided into two types depending on the type of vessel the thrombus is formed on:
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| * ''Large vessel disease'' involves the common and [[internal carotid artery|internal carotids]], [[vertebral artery|vertebral]], and the [[Circle of Willis]]. Diseases that may form thrombi in the large vessels include (in descending incidence): atherosclerosis, [[vasoconstriction]] (tightening of the artery), [[Aortic dissection|aortic]], [[carotid artery dissection|carotid]] or [[vertebral artery dissection]], various inflammatory diseases of the blood vessel wall ([[Takayasu arteritis]], [[giant cell arteritis]], [[vasculitis]]), noninflammatory vasculopathy, [[Moyamoya disease]] and [[fibromuscular dysplasia]].
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| * ''Small vessel disease'' involves the smaller arteries inside the brain: branches of the [[circle of Willis]], [[middle cerebral artery]], stem, and arteries arising from the distal vertebral and [[basilar artery]]. Diseases that may form thrombi in the small vessels include (in descending incidence): lipohyalinosis (build-up of fatty hyaline matter in the blood vessel as a result of high blood pressure and aging) and fibrinoid degeneration (stroke involving these vessels are known as [[lacunar infarcts]]) and microatheroma (small atherosclerotic plaques).
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| ;Embolic stroke
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| Embolic stroke refers to the blockage of an artery by an [[embolus]], a traveling particle or debris in the arterial bloodstream originating from elsewhere. An embolus is most frequently a thrombus, but it can also be a number of other substances including [[fat]] (e.g. from [[bone marrow]] in a [[Bone fracture|broken bone]]), air, [[cancer]] cells or clumps of [[bacteria]] (usually from infectious [[endocarditis]]).
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| Because an embolus arises from elsewhere, local therapy only solves the problem temporarily. Thus, the source of the embolus must be identified. Because the embolic blockage is sudden in onset, symptoms usually are maximal at start. Also, symptoms may be transient as the embolus is partially resorbed and moves to a different location or dissipates altogether.
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| Emboli most commonly arise from the [[heart]] (especially in [[atrial fibrillation]]) but may originate from elsewhere in the arterial tree. In [[paradoxical embolism]], a [[deep vein thrombosis]] embolises through an [[atrial septal defect|atrial]] or [[ventricular septal defect]] in the heart into the brain.
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| Cardiac causes can be distinguished between high- and low-risk:<ref name="ay">{{cite journal | author= Ay H; Furie KL; Singhal A; Smith WS; Sorensen AG; Koroshetz WJ | title= An evidence-based causative classification system for acute ischemic stroke | journal=Ann Neurol | year=2005 | pages=688-97 | volume=58 | issue=5 | pmid=16240340 }}</ref>
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| * High risk: [[atrial fibrillation]] and [[paroxysmal atrial fibrillation]], [[Rheumatic fever|rheumatic disease]] of the [[mitral valve|mitral]] or [[aortic valve]] disease, [[artificial heart valve]]s, known cardiac thrombus of the atrium or vertricle, [[sick sinus syndrome]], sustained [[atrial flutter]], recent [[myocardial infarction]], chronic myocardial infarction together with [[ejection fraction]] <28 percent, symptomatic [[congestive heart failure]] with ejection fraction <30 percent, [[dilated cardiomyopathy]], [[Libman-Sacks endocarditis]], [[Marantic endocarditis]], [[infective endocarditis]], [[papillary fibroelastoma]], [[left atrial myxoma]] and [[coronary artery bypass graft]] (CABG) surgery
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| * Low risk/potential: calcification of the annulus (ring) of the mitral valve, [[patent foramen ovale]] (PFO), atrial septal [[aneurysm]], atrial septal aneurysm ''with'' patent foramen ovale, left ventricular aneurysm without thrombus, isolated left atrial "smoke" on [[echocardiography]] (no [[mitral stenosis]] or atrial fibrillation), complex atheroma in the [[ascending aorta]] or proximal arch
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| ;Systemic hypoperfusion
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| Systemic hypoperfusion is the reduction of blood flow to all parts of the body. It is most commonly due to [[Heart-lung machine|cardiac pump]] failure from [[cardiac arrest]] or arrhythmias, or from reduced [[cardiac output]] as a result of [[myocardial infarction]], [[pulmonary embolism]], [[pericardial effusion]], or bleeding. [[Hypoxia (medical)|Hypoxemia]] (low blood oxygen content) may precipitate the hypoperfusion. Because the reduction in blood flow is global, all parts of the brain may be affected, especially "watershed" areas - border zone regions supplied by the major cerebral arteries. Blood flow to these areas does not necessarily stop, but instead it may lessen to the point where brain damage can occur. This phenomenon is also referred to as "last meadow" to point to the fact that in irrigation the last meadow receives the least amount of water.
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| ;Venous thrombosis
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| [[Cerebral venous sinus thrombosis]] leads to stroke due to locally increased venous pressure, which exceeds the pressure generated by the arteries. Infarcts are more likely to undergo hemorrhagic transformation (leaking of blood into the damaged area) than other types of ischemic stroke.
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| ===Hemorrhagic stroke===
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| [[Image:Intracerebral heamorrage 2.jpg|left|thumb|170px|[[CT scan]] showing an intracerebral hemorrhage.]]
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| {{main|Intracranial hemorrhage|intracerebral hemorrhage}}
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| Intracranial hemorrhage is the accumulation of blood anywhere within the skull vault. A distinction is made between [[intra-axial hemorrhage]] (blood inside the brain) and [[extra-axial hemorrhage]] (blood inside the skull but outside the brain).
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| Intra-axial hemorrhage is due to [[intraparenchymal hemorrhage]] or [[intraventricular hemorrhage]] (blood in the ventricular system).
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| The main types of extra-axial hemorrhage are [[epidural hematoma]] (bleeding between the [[dura mater]] and the skull), [[subdural hematoma]] (in the [[subdural space]]) and [[subarachnoid hemorrhage]] (between the [[arachnoid mater]] and [[pia mater]]). Most of the hemorrhagic stroke syndromes have specific symptoms (e.g. [[headache]], previous [[head injury]]).
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| [[Intracerebral hemorrhage]] (ICH) is bleeding directly into the brain tissue, forming a gradually enlarging [[hematoma]] (pooling of blood). It generally occurs in small arteries or arterioles and is commonly due to [[hypertension]], trauma, [[Haemophilia|bleeding disorders]], [[amyloid angiopathy]], illicit drug use (e.g. [[amphetamines]] or [[cocaine]]), and vascular malformations.
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| The hematoma enlarges until pressure from surrounding tissue limits its growth, or until it decompresses by emptying into the [[ventricular system]], [[cerebrospinal fluid|CSF]] or the pial surface.
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| A third of intracerebral bleed is into the brain's ventricles. ICH has a [[mortality rate]] of 44 percent after 30 days, higher than ischemic stroke or even the very deadly subarachnoid hemorrhage.
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| ==Signs and symptoms==
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| Stroke [[symptom]]s typically develop rapidly (seconds to minutes). The symptoms of a stroke are related to the anatomical location of the damage; nature and severity of the symptoms can therefore vary widely. Ischemic strokes usually only affect regional areas of the brain perfused by the blocked artery. Hemorrhagic strokes can affect local areas, but often can also cause more global symptoms due to bleeding and increased intracranial pressure. On the basis of the history and [[neurological examination]], as well as the presence of risk factors, a doctor can rapidly diagnose the ''anatomical'' nature of the stroke (i.e. which part of the brain is affected), even if the exact cause is not yet known.
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| If the area of the brain affected contains one of the three prominent [[Neural pathway|Central nervous system pathways]]—the [[spinothalamic tract]], [[corticospinal tract]], and [[dorsal column]] ([[medial lemniscus]]), symptoms may include:
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| * [[hemiplegia]] and [[central facial palsy|muscle weakness of the face]]
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| * numbness
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| * reduction in sensory or vibratory sensation
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| In most cases, the symptoms affect only one side of the body (unilateral). The defect in the brain is ''usually'' on the opposite side of the body (depending on which part of the brain is affected). However, the presence of any one of these symptoms does not necessarily suggest a stroke, since these pathways also travel in the [[spinal cord]] and any lesion there can also produce these symptoms.
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| In addition to the above CNS pathways, the ''[[brainstem]]'' also consists of the 12 [[cranial nerves]]. A stroke affecting the brainstem therefore can produce symptoms relating to deficits in these cranial nerves:
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| * altered smell, taste, hearing, or vision (total or partial)
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| * drooping of eyelid ([[ptosis (eyelid)|ptosis]]) and weakness of [[Extraocular muscles|ocular muscles]]
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| * decreased reflexes: gag, swallow, pupil reactivity to light
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| * decreased sensation and [[central facial palsy|muscle weakness of the face]]
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| * [[Balance disorder|balance problems]] and [[nystagmus]]
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| * altered breathing and heart rate
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| * weakness in [[sternocleidomastoid muscle]] with inability to turn head to one side
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| * weakness in tongue (inability to protrude and/or move from side to side)
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| If the ''[[cerebral cortex]]'' is involved, the CNS pathways can again be affected, but also can produce the following symptoms:
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| * [[aphasia]] (inability to speak or understand language from involvement of [[Broca's area|Broca's]] or [[Wernicke's area]])
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| * [[apraxia]] (altered voluntary movements)
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| * [[visual field]] defect
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| * memory deficits (involvement of [[temporal lobe]])
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| * [[hemineglect]] (involvement of [[parietal lobe]])
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| * disorganized thinking, confusion, [[hypersexual]] gestures (with involvement of frontal lobe)
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| * [[anosognosia]] (persistent denial of the existence of a, usually stroke-related, deficit)
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| If the ''[[cerebellum]]'' is involved, the patient may have the following:
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| * trouble walking
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| * altered movement coordination
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| * [[Vertigo (medical)|vertigo]] and or disequilibrium
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| [[Unconsciousness|Loss of consciousness]], headache, and vomiting usually occurs more often in hemorrhagic stroke than in thrombosis because of the increased intracranial pressure from the leaking blood compressing on the brain.
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| If symptoms are maximal at onset, the cause is more likely to be a subarachnoid hemorrhage or an embolic stroke.
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| ==Pathophysiology==
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| Ischemic stroke occurs due to a loss of blood supply to part of the brain, initiating the [[ischemic cascade]]. Brain tissue ceases to function if deprived of oxygen for more than 60 to 90 seconds and after a few hours will suffer irreversible injury possibly leading to death of the tissue, i.e., [[infarction]]. Atherosclerosis may disrupt the blood supply by narrowing the lumen of blood vessels leading to a reduction of blood flow, by causing the formation of blood clots within the vessel, or by releasing showers of small [[emboli]] through the disintegration of atherosclerotic plaques. Embolic infarction occurs when emboli formed elsewhere in the circulatory system, typically in the heart as a consequence of atria fibriliation, or in the carotid arteries. These break off, enter the cerebral circulation, then lodge in and occlude brain blood vessels.
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| Due to [[Anastomosis|collateral circulation]], within the region of brain tissue affected by ischemia there is a spectrum of severity. Thus, part of the tissue may immediately die while other parts may only be injured and could potentially recover. The ischemia area where tissue might recover is referred to as the ''ischemic penumbra''.
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| As oxygen or glucose becomes depleted in ischemic brain tissue, the production of [[high energy phosphate]] compounds such as adenosine triphosphate (ATP) fails leading to failure of energy dependent processes (such as ion pumping) necessary for tissue cell survival. This sets off a series of interrelated events that result in cellular injury and death. A major cause of neuronal injury is release of the excitatory neurotransmitter glutamate. The concentration of glutamate outside the cells of the nervous system is normally kept low by so-called uptake carriers, which are powered by the concentration gradients of ions (mainly Na<sup>+</sup>) across the cell membrane. However, stroke cuts off the supply of oxygen and glucose which powers the ion pumps maintaining these gradients. As a result the transmembrane ion gradients run down, and glutamate transporters reverse their direction, releasing glutamate into the extracellular space. Glutamate acts on receptors in nerve cells (especially NMDA receptors), producing an influx of calcium which activates enzymes that digest the cells' proteins, lipids and nuclear material. Calcium influx can also lead to the failure of [[mitochondria]], which can lead further toward energy depletion and may trigger cell death due to [[apoptosis]].
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| Ischaemia also induces production of [[Radical (chemistry)|oxygen free radicals]] and other [[reactive oxygen species]]. These react with and damage a number of cellular and extracellular elements. Damage to the blood vessel lining or [[endothelium]] is particularly important. In fact, many antioxidant neuroprotectants such as [[uric acid]] and [[NXY-059]] work at the level of the endothelium and not in the brain ''per se''. Free radicals also directly initiate elements of the [[apoptosis]] cascade by means of [[redox signaling]] .<!--
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| --><ref name="NINDS1999"/>
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| These processes are the same for any type of ischemic tissue and are referred to collectively as the ''ischemic cascade''. However, brain tissue is especially vulnerable to ischemia since it has little respiratory reserve and is completely dependent on [[aerobic metabolism]], unlike most other organs.
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| Brain tissue survival can be improved to some extent if one or more of these processes is inhibited. Drugs that scavenge [[Reactive oxygen species]], inhibit [[apoptosis]], or inhibit excitotoxic neurotransmitters, for example, have been shown experimentally to reduce tissue injury due to ischemia. Agents that work in this way are referred to as being ''neuroprotective''. Until recently, human [[clinical trial]]s with neuroprotective agents have failed, with the probable exception of deep barbiturate coma. However, more recently [[NXY-059]], the disulfonyl derivative of the radical-scavenging spintrap phenylbutylnitrone, is [http://content.nejm.org/cgi/content/short/354/6/588 reported] be neuroprotective in stroke. This agent appears to work at the level of the blood vessel lining or [[endothelium]]. Unfortunately, after producing favorable results in one large-scale clinical trial, a second trial failed to show favorable results.<ref name="NINDS1999"/>
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| In addition to injurious effects on brain cells, ischemia and infarction can result in loss of structural integrity of brain tissue and blood vessels, partly through the release of matrix metalloproteases, which are zinc- and calcium-dependent enzymes that break down collagen, [[Hyaluronan|hyaluronic acid]], and other elements of [[connective tissue]]. Other proteases also contribute to this process. The loss of vascular structural integrity results in a breakdown of the protective [[blood brain barrier]] that contributes to [[cerebral edema]], which can cause secondary progression of the brain injury.
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| As is the case with any type of [[Traumatic brain injury|brain injury]], the [[immune system]] is activated by cerebral infarction and may under some circumstances exacerbate the injury caused by the infarction. Inhibition of the [[Inflammation|inflammatory response]] has been shown experimentally to reduce tissue injury due to cerebral infarction, but this has not proved out in clinical studies.
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| Hemorrhagic strokes result in tissue injury by causing compression of tissue from an expanding [[hematoma]] or hematomas. This can distort and injure tissue. In addition, the pressure may lead to a loss of blood supply to affected tissue with resulting infarction, and the blood released by brain hemorrhage appears to have direct toxic effects on brain tissue and vasculature.<ref name="NINDS1999"/>
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| ==Diagnosis== | | ==Diagnosis== |
| Stroke is diagnosed through several techniques: a neurological examination, [[CT scan]]s (most often without contrast enhancements) or [[MRI scan]]s, [[Doppler ultrasound]], and [[arteriography]]. The diagnosis of stroke itself is clinical, with assistance from the imaging techniques. Imaging techniques also assist in determining the subtypes and cause of stroke. There is yet no commonly used [[blood test]] for the stroke diagnosis itself, though blood tests may be of help in finding out the likely cause of stroke.<ref name="hill2005">{{cite journal | author= Hill M | title= Diagnostic Biomarkers for Stroke: A Stroke Neurologist's Perspective | journal= Clin Chem | year=2005 | pages=2001-2002 | volume=51 | issue=11 | id=PMID 16244286 }}</ref>
| | [[Ischemic stroke history and symptoms|History and Symptoms]] | [[Ischemic stroke physical examination|Physical Examination]] | [[Ischemic stroke laboratory findings|Laboratory Findings]] | [[Ischemic stroke electrocardiogram|Electrocardiogram]] | [[Ischemic stroke CT|CT]] | [[Ischemic stroke MRI|MRI]] | [[Ischemic stroke echocardiography|Echocardiography]] | [[Ischemic stroke ultrasound|Ultrasound]] | [[Ischemic stroke other imaging findings|Other Imaging Findings]] |
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| ===Physical examination===
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| A [[systematic review]] found that acute facial paresis, arm drift, or abnormal speech are the best findings.<ref name="pmid15900010">{{cite journal |author=Goldstein L, Simel D |title=Is this patient having a stroke? |journal=JAMA |volume=293 |issue=19 |pages=2391-402 |year=2005 |id=PMID 15900010 | doi=10.1001/jama.296.16.2012 | url=http://jama.ama-assn.org/cgi/content/full/296/16/2012}}</ref>
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| ===Imaging===
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| For diagnosing ischemic stroke in the emergency setting:<ref name="pmid17258669">{{cite journal | last=Chalela | first=J | coauthors=Kidwell C, Nentwich L et al. | title=Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison | journal=Lancet | volume=369 | issue=9558 | pages=293-8 | year=2007 | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=17258669 | pmid=17258669 | accessdate=2008-01-22 }}</ref>
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| * [[CT scan]]s (''without'' contrast enhancements)
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| : [[sensitivity (tests)|sensitivity]]= 16%
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| : [[specificity (tests)|specificity]]= 96%
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| * [[MRI scan]]
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| : sensitivity= 83%
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| : specificity= 98%
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| For diagnosing hemorrhagic stroke in the emergency setting:
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| * CT scans (''without'' contrast enhancements)
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| : sensitivity= 89%
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| : specificity= 100%
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| * MRI scan
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| : sensitivity= 81%
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| : specificity= 100%
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| For detecting chronic hemorrhages, MRI scan is more sensitive.<ref name="pmid15494579">{{cite journal | last=Kidwell | first=C | coauthors=Chalela J, Saver J et al. | title=Comparison of MRI and CT for detection of acute intracerebral hemorrhage | journal=JAMA | volume=292 | issue=15 | pages=1823–30 | year=2004 | url=http://jama.ama-assn.org/cgi/content/full/292/15/1823 | pmid=15494579 | accessdate=2008-01-22 }}</ref>
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| For the assessment of stable stroke, nuclear medicine scans SPECT and PET/CT may be helpful. SPECT documents cerebral blood flow and PET with FDG isotope the metabolic activity of the neurons.
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| ===Underlying etiology===
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| When a stroke has been diagnosed, various other studies may be performed to determine the underlying etiology. With the current treatment and diagnosis options available, it is of particular importance to determine whether there is a peripheral source of [[embolus|emboli]]. Test selection may vary, since the cause of stroke varies with age, [[comorbidity]] and the clinical presentation. Commonly used techniques include:
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| * an [[medical ultrasonography|ultrasound/doppler study]] of the [[carotid artery|carotid arteries]] (to detect [[carotid stenosis]]) or [[carotid artery dissection|dissection of the precerebral artieries]]
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| * an [[electrocardiogram]] (ECG) and [[echocardiogram]] (to identify [[cardiac arrhythmia|arrhythmias]] and resultant clots in the heart which may spread to the brain vessels through the bloodstream)
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| * a [[Holter monitor]] study to identify intermittent arrhythmias
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| * an [[angiogram]] of the cerebral vasculature (if a bleed is thought to have originated from an [[aneurysm]] or [[arteriovenous malformation]])
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| * blood tests to determine [[hypercholesterolemia]], [[bleeding diathesis]] and some rarer causes such as [[homocysteinuria]]
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| ==Prevention==
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| [[Prevention (medical)|Prevention]] of stroke can work at various levels including:
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| #''primary prevention'' - the reduction of risk factors across the board, by [[public health]] measures such as reducing smoking and the other behaviours that increase risk;
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| #''secondary prevention'' - actions taken to reduce the risk in those who already have disease or risk factors that may have been identified through [[Screening (medicine)|screening]]; and
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| #''tertiary prevention'' - actions taken to reduce the risk of complications (including further strokes) in people who have already had a stroke.
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| The most important modifiable risk factors for stroke are hypertension, [[heart disease]], diabetes, and cigarette smoking. Other risks include heavy [[Alcoholic beverage|alcohol consumption]] (see [[Alcohol consumption and health]]), high blood cholesterol levels, illicit drug use, and genetic or congenital conditions. Family members may have a genetic tendency for stroke or share a lifestyle that contributes to stroke. Higher levels of [[Von Willebrand factor]] are more common amongst people who have had ischemic stroke for the first time.<ref>{{cite journal | author=Bongers T, de Maat M, van Goor M et al. | title=High von Willebrand factor levels increase the risk of first ischemic stroke: influence of ADAMTS13, inflammation, and genetic variability. | journal=Stroke | volume=37 | issue=11 | pages=2672–7 | year=2006 | pmid=16990571 }}</ref><!--
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| --> The results of this study found that the only significant genetic factor was the person's [[blood type]]. Having had a stroke in the past greatly increases one's risk of future strokes.
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| One of the most significant stroke risk factors is advanced age. 95% of strokes occur in people age 45 and older, and two-thirds of strokes occur in those over the age of 65.<ref name="Senelick1994"/><!--
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| --><ref name="NINDS1999">{{cite web | author=National Institute of Neurological Disorders and Stroke (NINDS) | authorlink=National Institute of Neurological Disorders and Stroke | year=1999 | title=Stroke: Hope Through Research | url=http://www.ninds.nih.gov/disorders/stroke/detail_stroke.htm | publisher=National Institutes of Health}}</ref> A person's risk of dying if he or she does have a stroke also increases with age. However, stroke can occur at any age, including in fetuses.
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| [[Sickle-cell disease|Sickle cell anemia]], which can cause [[blood cell]]s to clump up and block blood vessels, also increases stroke risk. Stroke is the second leading killer of people under 20 who suffer from sickle-cell anemia.<!--
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| --><ref name="NINDS1999"/>
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| Men are 1.25 times more likely to suffer strokes than women,<!--
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| --><ref name="NINDS1999"/> yet 60% of deaths from stroke occur in women.<!--
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| --><ref name="Villarosa1993"/> Since women live longer, they are older on average when they have their strokes and thus more often killed (NIMH 2002).<!--
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| --><ref name="NINDS1999"/> Some risk factors for stroke apply only to women. Primary among these are pregnancy, childbirth, menopause and the treatment thereof ([[Hormone replacement therapy|HRT]]).
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| Prevention is an important public health concern. Identification of patients with treatable risk factors for stroke is paramount. Treatment of risk factors in patients who have already had strokes (secondary prevention) is also very important as they are at high risk of subsequent events compared with those who have never had a stroke. Medication or [[Pharmacology|drug therapy]] is the most common method of stroke prevention. Aspirin (usually at a low dose of 75 mg) is recommended for the primary and secondary prevention of stroke. Also see [[Antiplatelet drug]] treatment. Treating [[hypertension]], [[diabetes mellitus]], [[smoking cessation]], control of [[hypercholesterolemia]], [[physical exercise]], and avoidance of illicit drugs and excessive alcohol consumption are all recommended ways of reducing the risk of stroke.<ref name="americanheart risk">American Heart Association. (2007). [http://www.americanheart.org/presenter.jhtml?identifier=4716 Stroke Risk Factors] Americanheart.org. Retrieved on January 22, 2007.</ref>
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| In patients who have strokes due to abnormalities of the heart, such as [[atrial fibrillation]], [[anticoagulation]] with medications such as warfarin is often necessary for stroke prevention.<ref>American Heart Association. (2007). [http://www.americanheart.org/presenter.jhtml?identifier=4451 Atrial Fibrillation] Americanheart.org. Retrieved on January 22, 2007.</ref>
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| Procedures such as [[carotid endarterectomy]] or carotid [[angioplasty]] can be used to remove significant atherosclerotic narrowing (stenosis) of the [[carotid artery]], which supplies blood to the brain. These procedures have been shown to prevent stroke in certain patients, especially where carotid stenosis leads to [[ischemic]] events such as [[transient ischemic attack]]. (The value and role of carotid artery ultrasound scanning in [[Screening (medicine)|screening]] has yet to be established.)
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| A [[meta-analysis]] concluded that lowering [[homocysteine]] with [[folic acid]] and other supplements may reduce stroke.<ref name="pmid17544768">{{cite journal |author=Wang X, Qin X, Demirtas H, ''et al'' |title=Efficacy of folic acid supplementation in stroke prevention: a meta-analysis |journal=Lancet |volume=369 |issue=9576 |pages=1876-82 |year=2007 |pmid=17544768 |doi=10.1016/S0140-6736(07)60854-X}}</ref> However, the two largest [[randomized controlled trial]]s included in the meta-analysis had conflicting results. Lonn reported positve results;<ref name="pmid16531613">{{cite journal |author=Lonn E, Yusuf S, Arnold MJ, ''et al'' |title=Homocysteine lowering with folic acid and B vitamins in vascular disease |journal=N. Engl. J. Med. |volume=354 |issue=15 |pages=1567-77 |year=2006 |pmid=16531613 |doi=10.1056/NEJMoa060900}}</ref> whereas the trial by Toole was negative.<ref name="pmid14762035">{{cite journal |author=Toole JF, Malinow MR, Chambless LE, ''et al'' |title=Lowering homocysteine in patients with ischemic stroke to prevent recurrent stroke, myocardial infarction, and death: the Vitamin Intervention for Stroke Prevention (VISP) randomized controlled trial |journal=JAMA |volume=291 |issue=5 |pages=565-75 |year=2004 |pmid=14762035 |doi=10.1001/jama.291.5.565}}</ref>
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| ==Treatment== | | ==Treatment== |
| ===Early assessment===
| | [[Stroke early assessment|Early assessment]] | [[Stroke medical therapy|Medical Therapy]] | [[Stroke surgery|Surgery]] | [[Stroke rehabilitation|Rehabilitation]] | [[Ischemic stroke primary prevention|Primary prevention]] | [[Ischemic stroke secondary prevention|Secondary prevention]] | [[Stroke cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Stroke future or investigational therapies|Future or Investigational Therapies]] |
| Early recognition of the signs of stroke is generally regarded as important. Only detailed [[physical examination]] and [[medical imaging]] provide information on the presence, type, and extent of stroke, and hence hospital attendance — even if the symptoms were brief — is advised.
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| Studies show that patients treated in hospitals with a dedicated Stroke Team or Stroke Unit and a specialized care program for stroke patients have improved odds of recovery.
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| ===Ischemic stroke===
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| An ischemic stroke is due to a [[thrombus]] (blood clot) occluding a cerebral artery, a patient is given [[antiplatelet drug|antiplatelet medication]] ([[aspirin]], [[clopidogrel]], [[dipyridamole]]), or [[anticoagulant]] medication ([[warfarin]]), dependent on the cause, when this type of stroke has been found. Hemorrhagic stroke must be ruled out with medical imaging, since this therapy would be harmful to patients with that type of stroke.
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| Whether thrombolysis is performed or not, the following investigations are required:
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| * Stroke symptoms are documented, often using scoring systems such as the National Institutes of Health Stroke Scale, the [[Cincinnati Stroke Scale]], and the Los Angeles Prehospital Stroke Screen. The Cincinnati Stroke Scale is used by [[emergency medical technician]]s (EMTs) to determine whether a patient needs transport to a stroke center.
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| * A [[Computed axial tomography|CT scan]] is performed to rule out hemorrhagic stroke
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| * Blood tests, such as a [[full blood count]], [[coagulation]] studies ([[prothrombin time|PT/INR]] and [[Partial thromboplastin time|APTT]]), and tests of [[electrolyte]]s, [[renal function]], [[liver function tests]] and [[glucose]] levels are carried out.
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| Other immediate strategies to protect the brain during stroke include ensuring that [[blood sugar]] is as normal as possible (such as commencement of an insulin sliding scale in known [[diabetes|diabetics]]), and that the stroke patient is receiving adequate [[oxygen]] and [[intravenous fluid]]s. The patient may be positioned so that his or her head is flat on the stretcher, rather than sitting up, since studies have shown that this increases blood flow to the brain. Additional therapies for ischemic stroke include [[aspirin]] (50 to 325 mg daily), [[clopidogrel]] (75 mg daily), and combined aspirin and [[dipyridamole]] extended release (25/200 mg twice daily).
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| It is common for the [[blood pressure]] to be [[arterial hypertension|elevated]] immediately following a stroke. Studies indicated that while high blood pressure causes stroke, it is actually beneficial in the emergency period to allow better blood flow to the brain.
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| If studies show [[carotid stenosis]], and the patient has residual function in the affected side, [[carotid endarterectomy]] (surgical removal of the stenosis) may decrease the risk of recurrence if performed rapidly after stroke.
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| If the stroke has been the result of [[cardiac arrhythmia]] with cardiogenic emboli, treatment of the arrhythmia and [[anticoagulation]] with [[warfarin]] or high-dose aspirin may decrease the risk of recurrence. Stroke prevention treatment for a common arrhythmia, [[atrial fibrillation]], is determined according to the [[CHADS Score|CHADS/CHADS2 system]].
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| ====Thrombolysis====
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| In increasing numbers of primary stroke centers, pharmacologic [[thrombolysis]] ("clot busting") with the drug [[tissue plasminogen activator]], '''tPA''', is used to dissolve the clot and unblock the artery. However, the use of tPA in acute stroke is controversial. On one hand, it is endorsed by the [[American Heart Association]] and the American Academy of Neurology as the recommended treatment for acute stroke within three hours of onset of symptoms as long as there are not other contraindications (such as abnormal lab values, high blood pressure, or recent surgery). This position for tPA is based upon the findings of two studies by one group of investigators<ref>{{cite journal |author= |title=Tissue plasminogen activator for acute ischemic stroke. The National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group |journal=New England Journal of Medicine |volume=333 |issue=24 |pages=1581–7 |year=1995 |pmid=7477192 |url=http://content.nejm.org/cgi/content/full/333/24/1581}}</ref> which showed that tPA improves the chances for a good neurological outcome. When administered within the first three hours, 39% of all patients who were treated with tPA had a good outcome at three months, only 26% of placebo controlled patients had a good functional outcome. However, in the NINDS trial 6.4% of patients with large strokes developed substantial brain hemorrhage as a complication from being given tPA. tPA is often misconstrued as a "magic bullet" and it is important for patients to be aware that despite the study that supports its use, some of the data were flawed and the safety and efficacy of tPA is controversial. A recent study found the mortality to be higher among patients receiving tPA versus those who did not.<ref name="Dubinsky06">{{cite journal | last =Dubinsky | first = R| authorlink = | coauthors =Lai SM | title =Mortality of stroke patients treated with thrombolysis: analysis of nationwide inpatient sample | journal =Neurology | volume =66 | issue =11 | pages =1742–1744 | publisher = | date =2006 | url = | doi = | id =PMID 16769953 | accessdate =2007-01-22 }} </ref> Additionally, it is the position of the American Academy of Emergency Medicine that objective evidence regarding the efficacy, safety, and applicability of tPA for acute ischemic stroke is insufficient to warrant its classification as [[standard of care]].<ref>{{cite web|url=http://www.aaem.org/positionstatements/thrombolytictherapy.shtml |title=Position Statement on the Use of Intravenous Thrombolytic Therapy in the Treatment of Stroke |publisher=American Academy of Emergency Medicine |accessdate=2008-01-25}}</ref> Until additional evidence clarifies such controversies, physicians are advised to use their discretion when considering its use. Given the cited absence of definitive evidence, AAEM believes it is inappropriate to claim that either use or non-use of intravenous thrombolytic therapy constitutes a standard of care issue in the treatment of stroke.
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| ====Mechanical thrombectomy====
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| Another intervention for acute ischemic stroke is removal of the offending thrombus directly. This is accomplished by inserting a catheter into the [[femoral artery]], directing it into the [[cerebral circulation]], and deploying a corkscrew-like device to ensnare the clot, which is then withdrawn from the body. In August 2004, based on data from the MERCI (Mechanical Embolus Removal in [[Cerebral ischemia|Cerebral Ischemia]]) Trial, the FDA cleared several of these devices, called the Merci X5 and X6 Retrievers.<ref>{{cite journal |author=Smith WS, Sung G, Starkman S, ''et al'' |title=Safety and efficacy of mechanical embolectomy in acute ischemic stroke: results of the MERCI trial |journal=Stroke |volume=36 |issue=7 |pages=1432-8 |year=2005 |pmid=15961709 |doi=10.1161/01.STR.0000171066.25248.1d|url=http://stroke.ahajournals.org/cgi/content/full/36/7/1432}}</ref><ref name="FDA2004-MerciRetriever">{{cite web | author=Celia Witten | year=2004 | title=Concentric Merci Retriever product licence |url=http://www.fda.gov/cdrh/pdf3/k033736.pdf | format=PDF | publisher=FDA}}</ref>
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| The newer generation Merci L5 Retriever was additionally used in the Multi MERCI trial.<ref>{{cite journal |author=Smith WS |title=Safety of mechanical thrombectomy and intravenous tissue plasminogen activator in acute ischemic stroke. Results of the multi Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trial, part I |journal=AJNR Am J Neuroradiol |volume=27 |issue=6 |pages=1177-82 |year=2006 |pmid=16775259 |url=http://www.ajnr.org/cgi/content/full/27/6/1177}}</ref><ref>{{cite journal |author=Smith WS, Sung G, Saver J, ''et al'' |title=Mechanical thrombectomy for acute ischemic stroke: final results of the Multi MERCI trial |journal=Stroke |volume=39 |issue=4 |pages=1205-12 |year=2008 |pmid=18309168 |doi=10.1161/STROKEAHA.107.497115}}</ref> Both the MERCI and Multi MERCI trials required the first pass with the Merci Retriever to be initiated within 8 hours of onset of symptoms.
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| ===Embolic stroke===
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| Anticoagulation can prevent recurrent stroke. Among patients with nonvalvular [[atrial fibrillation]], anticoagulation can reduce stroke by 60% while antiplatelet agents can reduce stroke by 20%.<ref name="pmid17577005">{{cite journal |author=Hart RG, Pearce LA, Aguilar MI |title=Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation |journal=Ann. Intern. Med. |volume=146 |issue=12 |pages=857-67 |year=2007 |pmid=17577005 |doi=}}</ref>. However, a recent [[meta-analysis]] suggests harm from anti-coagulation started early after an embolic stroke.<ref name="pmid17204681"> {{cite journal |author=Paciaroni M, Agnelli G, Micheli S, Caso V |title=Efficacy and safety of anticoagulant treatment in acute cardioembolic stroke: a meta-analysis of randomized controlled trials |journal=Stroke |volume=38 |issue=2 |pages=423-30 | year=2007 |pmid=17204681 |doi=10.1161/01.STR.0000254600.92975.1f }} [http://www.acpjc.org/Content/147/1/issue/ACPJC-2007-147-1-017.htm ACP JC synopsis ]</ref>
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| ===Hemorrhagic stroke===
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| Patients with bleeding into ([[intracerebral hemorrhage]]) or around the brain ([[subarachnoid hemorrhage]]), require [[neurosurgery|neurosurgical]] evaluation to detect and treat the cause of the bleeding. Anticoagulants and antithrombotics, key in treating ischemic stroke, can make bleeding worse and cannot be used in intracerebral hemorrhage. Patients are monitored and their blood pressure, blood sugar, and oxygenation are kept at optimum levels.
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| ===Care and rehabilitation===
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| [[Stroke rehabilitation]] is the process by which patients with disabling strokes undergo treatment to help them return to normal life as much as possible by regaining and relearning the skills of everyday living. It also aims to help the survivor understand and adapt to difficulties, prevent secondary complications and educate family members to play a supporting role.
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| A rehabilitation team is usually multidisciplinary as it involves staff with different skills working together to help the patient. These include nursing staff, [[physiotherapy]], [[occupational therapy]], [[speech and language therapy]], and usually a [[physician]] trained in [[rehabilitation medicine]]. Some teams may also include [[psychologists]], [[social work]]ers, and [[pharmacist]]s since at least one third of the patients manifest [[post stroke depression]].
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| Good [[nursing care]] is fundamental in maintaining [[Skin|skin care]], feeding, hydration, positioning, and monitoring [[vital signs]] such as temperature, pulse, and blood pressure. Stroke rehabilitation begins almost immediately.
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| For most stroke patients, [[physical therapy]] (PT) and [[occupational therapy]] (OT) are the cornerstones of the rehabilitation process. Often, [[assistive technology]] such as a [[wheelchair]], walkers, canes, and [[orthosis]] may be beneficial. PT and OT have overlapping areas of working but their main attention fields are; PT involves re-learning functions as transferring, walking and other gross motor functions. OT focusses on exercises and training to help relearn everyday activities known as the [[Activities of daily living]] (ADLs) such as eating, drinking, dressing, bathing, cooking, reading and writing, and toileting. [[Speech and language therapy]] is appropriate for patients with problems understanding speech or written words, problems forming speech and problems with eating (swallowing).
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| Patients may have particular problems, such as complete or partial inability to swallow, which can cause swallowed material to pass into the lungs and cause [[aspiration pneumonia]]. The condition may improve with time, but in the interim, a [[Nasogastric intubation|nasogastric tube]] may be inserted, enabling liquid food to be given directly into the stomach. If swallowing is still unsafe after a week, then a [[percutaneous endoscopic gastrostomy]] (PEG) tube is passed and this can remain indefinitely.
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| Stroke rehabilitation should be started as immediately as possible and can last anywhere from a few days to several months. Most return of function is seen in the first few days and weeks, and then improvement falls off with the "window" considered officially by U.S. state rehabilitation units and others to be closed after six months, with little chance of further improvement. However, patients have been known to continue to improve for years, regaining and strengthening abilities like writing, walking, running, and talking. Daily rehabilitation exercises should continue to be part of the stroke patient's routine. Complete recovery is unusual but not impossible and most patients will improve to some extent : a correct diet and exercise are known to help the brain to self-recover.
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| ==Prognosis==
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| Disability affects 75% of stroke survivors enough to decrease their employability.<!--
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| --><ref name="Coffey2000">{{cite book | author=Coffey C. Edward, Cummings Jeffrey L, Starkstein Sergio, Robinson Robert | title=Stroke - The American Psychiatric Press Textbook of Geriatric Neuropsychiatry | year=2000 | edition=Second Edition | pages=601–617 | location=Washington DC | publisher=American Psychiatric Press}}</ref>
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| Stroke can affect patients physically, mentally, emotionally, or a combination of the three. The results of stroke vary widely depending on size and location of the lesion.<!--
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| --><ref name="Stanford2005">{{cite web | author=Stanford Hospital & Clinics | title=Cardiovascular Diseases: Effects of Stroke | url=http://www.stanfordhospital.com/healthLib/atoz/cardiac/effects.html | accessyear=2005}}</ref>
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| Dysfunctions correspond to areas in the brain that have been damaged.
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| Some of the physical disabilities that can result from stroke include [[paralysis]], numbness, [[pressure sore]]s, [[pneumonia]], [[incontinence]], [[apraxia]] (inability to perform learned movements), difficulties carrying out daily activities, appetite loss, [[vision loss]], and [[pain]]. If the stroke is severe enough, or in a certain location such as parts of the brainstem, [[coma]] or [[death]] can result.
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| Emotional problems resulting from stroke can result from direct damage to emotional centers in the brain or from frustration and difficulty adapting to new limitations. Post-stroke emotional difficulties include [[anxiety]], [[panic attack]]s, [[flat affect]] (failure to express emotions), [[mania]], apathy, and [[psychosis]].
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| 30 to 50% of stroke survivors suffer [[post stroke depression]], which is characterized by lethargy, irritability, [[Sleep disorder|sleep disturbances]], lowered [[Self-esteem|self esteem]], and withdrawal.<!--
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| --><ref name="Senelick1994">{{cite book | author=Senelick Richard C., Rossi, Peter W., Dougherty, Karla | title=Living with Stroke: A Guide For Families | year=1994 | publisher=Contemporary Books, Chicago}}</ref>
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| [[Clinical depression|Depression]] can reduce motivation and worsen outcome, but can be treated with [[antidepressant]]s.
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| [[Emotional lability]], another consequence of stroke, causes the patient to switch quickly between emotional highs and lows and to express emotions inappropriately, for instance with an excess of laughing or crying with little or no provocation. While these expressions of emotion usually correspond to the patient's actual emotions, a more severe form of emotional lability causes patients to laugh and cry pathologically, without regard to context or emotion.<!--
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| --><ref name="Coffey2000"/>
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| Some patients show the opposite of what they feel, for example crying when they are happy.<!--
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| --><ref name="Villarosa1993">{{cite book | author=Villarosa, Linda, Ed., Singleton, LaFayette, MD, Johnson, Kirk A. | title=Black Health Library Guide to Stroke | year=1993 | publisher=Henry Holt and Company, New York}}</ref>
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| Emotional lability occurs in about 20% of stroke patients.
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| Cognitive deficits resulting from stroke include perceptual disorders, [[Dysphasia|speech problems]], [[dementia]], and problems with attention and memory. A stroke sufferer may be unaware of his or her own disabilities, a condition called [[anosognosia]]. In a condition called [[hemispatial neglect]], a patient is unable to attend to anything on the side of space opposite to the damaged hemisphere.
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| Up to 10% of all stroke patients develop [[seizure]]s, most commonly in the week subsequent to the event; the severity of the stroke increases the likelihood of a seizure.<ref name=Reith1997>Reith J, Jorgensen HS, Nakayama H, Raaschou HO, Olsen TS. Seizures in acute stroke: predictors and prognostic significance. The Copenhagen Stroke Study. ''Stroke'' 1997;28:1585–9. PMID 9259753.</ref><ref name=Burn1997>Burn J, Dennis M, Bamford J, Sandercock P, Wade D, Warlow C. Epileptic seizures after a first stroke: the Oxfordshire Community Stroke Project. ''BMJ'' 1997;315:1582–7. PMID 9437276.</ref>
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| ==Epidemiology== | | == Case Studies == |
| Stroke could soon be the most common cause of death worldwide.<ref name=globalburden_lancet1997>{{cite journal |author=Murray CJ, Lopez AD |title=Mortality by cause for eight regions of the world: Global Burden of Disease Study |journal=Lancet |volume=349 |issue=9061 |pages=1269–76 |year=1997 |pmid=9142060 |doi=}}</ref> Stroke is the third leading cause of death in the Western world, after heart disease and cancer,<ref name="feigin2005"/> and causes 10% of deaths worldwide.<ref name="worldhealth2004_app2">{{cite book | title=The World health report 2004. Annex Table 2: Deaths by cause, sex and mortality stratum in WHO regions, estimates for 2002. | publisher=[[World Health Organization]] | date=2004 | location=Geneva | url=http://www.who.int/entity/whr/2004/en/report04_en.pdf }}</ref>
| | [[Stroke case study one|Case #1]] |
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| The [[incidence (epidemiology)|incidence]] of stroke increases exponentially from 30 years of age, and [[etiology]] varies by age.<ref name="ellekjaer1997">{{cite journal | last=Ellekjær | first=H | coauthors=Holmen J, Indredavik B, Terent A | title=Epidemiology of Stroke in Innherred, Norway, 1994 to 1996 : Incidence and 30-Day Case-Fatality Rate | journal=Stroke | volume=28 | pages=2180–2184 | date=1997 | url=http://stroke.ahajournals.org/cgi/content/abstract/strokeaha%3B28/11/2180 | accessdate=2008-01-22 | pmid=9368561 }}</ref>
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| ==History==
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| [[Image:Hippocrates.jpg|thumb|right|130px|Hippocrates first described the sudden paralysis that is often associated with stroke.]]
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| [[Hippocrates]] (460 to 370 BC) was first to describe the phenomenon of sudden [[paralysis]].
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| [[Apoplexy]], from the [[Greek language|Greek]] word meaning "struck down with violence,” first appeared in Hippocratic writings to describe this phenomenon.<!--
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| --><ref name="Stroke1996-Thompson">{{cite journal | author=Thompson JE | title=The evolution of surgery for the treatment and prevention of stroke. The Willis Lecture | journal=Stroke | year=1996 | pages=1427–34 | volume=27 | issue=8 | id=PMID 8711815 | url=http://stroke.ahajournals.org/cgi/content/full/27/8/1427}}</ref><!--
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| --><ref name="Merginet2001-Kopito">{{cite journal | author=Kopito, Jeff | title=A Stroke in Time | url=http://www.webasx.com/articles/strokeintime.html | journal=MERGINET.com | year=2001 | month=September | Volume=6 | issue=Number 9}}</ref>
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| The word ''stroke'' was used as a synonym for apoplectic seizure as early as 1599,<ref>R. Barnhart, ed. ''The Barnhart Concise Dictionary of Etymology'' (1995)</ref> and is a fairly literal translation of the Greek term.
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| In 1658, in his ''Apoplexia'', [[Johann Jakob Wepfer|Johann Jacob Wepfer]] (1620–1695) identified the cause of hemorrhagic stroke when he suggested that people who had died of apoplexy had bleeding in their brains.<!--
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| --><ref name="Stroke1996-Thompson"/><!--
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| --><ref name="NINDS1999"/>
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| Wepfer also identified the main arteries supplying the brain, the [[vertebral artery|vertebral]] and [[carotid artery|carotid arteries]], and identified the cause of ischemic stroke when he suggested that apoplexy might be caused by a blockage to those vessels.<!--
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| --><ref name="NINDS1999"/>
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| <br clear="both"/>
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| ==References==
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| {{reflist|2}}
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| ==Further reading==
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| * {{cite book | author = J. P. Mohr, Dennis Choi, James Grotta, Philip Wolf | title = Stroke: Pathophysiology, Diagnosis, and Management | publisher = Churchill Livingstone | location = New York | year = 2004 | id = ISBN 0-443-06600-0}}
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| * {{cite book | author=Perry, Thomas and Miller Frank | title='Pathology: A Dynamic Introduction to Medicine and Surgery | year=1961 | location=Boston | publisher=Little, Brown and Company}}
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| ==External links==
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| '''Detailed information'''
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| * ''The original text for this article was taken from the [[National Institute of Neurological Disorders and Stroke]] public domain resource at [http://www.ninds.nih.gov/health_and_medical/disorders/stroke.htm this page]''
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| * [http://www.medicine.mcgill.ca/strokengine/ StrokEngine] (McGill University, Montreal, Quebec, Canada) Focuses on stroke rehabilitation and interventions
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| * [http://www.doctorslounge.com/primary/articles/stroke_risk/index.htm Cerebrovascular disease and risk of stroke]
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| * {{cite web | title=What Happens During a Stroke | url=http://health-net-now.blogspot.com/2007/04/stroke-what-happens-during-stroke.html | publisher=NLM | accessdate=2007-04-15}} video
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| * [http://www.americanheart.org/presenter.jhtml?identifier=3053 "Heart Attack, Stroke and Cardiac Arrest Warning Signs," from the American Heart Association]
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| * [http://www.strokemd.net StrokeMD.net]
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| * [http://www.childstroke.org.uk Study of Outcome of Childhood Stroke] UK
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| '''National organizations'''
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| * [http://www.strokeassociation.org/presenter.jhtml?identifier=1200037 American Stroke Association]
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| * [http://www.stroke.org/home National Stroke Association]
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| * [http://www.canadianstrokenetwork.ca Canadian Stroke Network]
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| * [http://www.rcsn.org Registry of the Canadian Stroke Network]
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| * [http://www.heartandstroke.ca Heart and Stroke Foundation of Canada]
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| * [http://www.stroke.org.uk The Stroke Association] UK
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| * [http://www.nasam.org National Stroke Association of Malaysia]
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