Classification
Strokes can be classified into two major categories: ischemic and hemorrhagic. Ischemic strokes are caused by interruption of the blood supply to the brain, while hemorrhagic strokes result from the rupture of aDefinition
In the 1970s theIschemic
In an ischemic stroke, blood supply to part of the brain is decreased, leading to dysfunction of the brain tissue in that area. There are four reasons why this might happen: #Hemorrhagic
There are two main types of hemorrhagic stroke: *Signs and symptoms
Stroke symptoms typically start suddenly, over seconds to minutes, and in most cases do not progress further. The symptoms depend on the area of the brain affected. The more extensive the area of the brain affected, the more functions that are likely to be lost. Some forms of stroke can cause additional symptoms. For example, in intracranial hemorrhage, the affected area may compress other structures. Most forms of stroke are not associated with aEarly recognition
Various systems have been proposed to increase recognition of stroke. Different findings are able to predict the presence or absence of stroke to different degrees. Sudden-onset face weakness, arm drift (i.e., if a person, when asked to raise both arms, involuntarily lets one arm drift downward) and abnormal speech are the findings most likely to lead to the correct identification of a case of stroke, increasing the likelihood by 5.5 when at least one of these is present. Similarly, when all three of these are absent, the likelihood of stroke is decreased (– likelihood ratio of 0.39). While these findings are not perfect for diagnosing stroke, the fact that they can be evaluated relatively rapidly and easily make them very valuable in the acute setting. A mnemonic to remember the warning signs of stroke isSubtypes
If the area of the brain affected includes one of the three prominentAssociated symptoms
Causes
Thrombotic stroke
In thrombotic stroke, a thrombus (blood clot) usually forms around atherosclerotic plaques. Since blockage of the artery is gradual, onset of symptomatic thrombotic strokes is slower than that of a hemorrhagic stroke. A thrombus itself (even if it does not completely block the blood vessel) can lead to an embolic stroke (see below) if the thrombus breaks off and travels in the bloodstream, at which point it is called an embolus. Two types of thrombosis can cause stroke: * ''Large vessel disease'' involves theEmbolic stroke
An embolic stroke refers to anCerebral hypoperfusion
Cerebral hypoperfusion is the reduction of blood flow to all parts of the brain. The reduction could be to a particular part of the brain depending on the cause. It is most commonly due toVenous thrombosis
Intracerebral hemorrhage
It generally occurs in small arteries or arterioles and is commonly due to hypertension, intracranial vascular malformations (includingOther
Other causes may include spasm of an artery. This may occur due toSilent stroke
A silent stroke is a stroke that does not have any outward symptoms, and people are typically unaware they have had a stroke. Despite not causing identifiable symptoms, a silent stroke still damages the brain and places the person at increased risk for both transient ischemic attack and major stroke in the future. Conversely, those who have had a major stroke are also at risk of having silent strokes. In a broad study in 1998, more than 11 million people were estimated to have experienced a stroke in the United States. Approximately 770,000 of these strokes were symptomatic and 11 million were first-ever silent MRI infarcts orPathophysiology
Ischemic
Ischemic stroke occurs because of a loss of blood supply to part of the brain, initiating the ischemic cascade. 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 smallHemorrhagic
Hemorrhagic strokes are classified based on their underlying pathology. Some causes of hemorrhagic stroke are hypertensive hemorrhage, rupturedDiagnosis
Stroke is diagnosed through several techniques: a neurological examination (such as the NIHSS), CT scans (most often without contrast enhancements) or MRI scans, 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 usedPhysical examination
AImaging
For diagnosing ischemic (blockage) stroke in the emergency setting: * CT scans (''without'' contrast enhancements) : sensitivity= 16% (less than 10% within first 3 hours of symptom onset) : specificity= 96% * MRI scan : sensitivity= 83% : specificity= 98% For diagnosing hemorrhagic stroke in the emergency setting: * CT scans (''without'' contrast enhancements) : sensitivity= 89% : specificity= 100% * MRI scan : sensitivity= 81% : specificity= 100% For detecting chronic hemorrhages, an MRI scan is more sensitive. For the assessment of stable stroke, nuclear medicine scans SPECT and PET/CT may be helpful. SPECT documents cerebral blood flow, whereas PET with an FDG isotope shows cerebral glucose metabolism. CT scans may not detect an ischemic stroke, especially if it is small, of recent onset, or in the brainstem or cerebellum areas (Underlying cause
When a stroke has been diagnosed, various other studies may be performed to determine the underlying cause. With the current treatment and diagnosis options available, it is of particular importance to determine whether there is a peripheral source of emboli. Test selection may vary since the cause of stroke varies with age,Misdiagnosis
Among people with ischemic strokes, misdiagnosis occurs 2 to 26% of the time. A "stroke chameleon" (SC) is stroke which is diagnosed as something else. People not having a stroke may also be misdiagnosed as a stroke. Giving thrombolytics (clot-busting) in such cases causes intracerebral bleeding 1 to 2% of the time, which is less than that of people with strokes. This unnecessary treatment adds to health care costs. Even so, the AHA/ASA guidelines state that starting intravenous tPA in possible mimics is preferred to delaying treatment for additional testing. Women, African-Americans, Hispanic-Americans, Asian and Pacific Islanders are more often misdiagnosed for a condition other than stroke when in fact having a stroke. In addition, adults under 44 years of age are seven times more likely to have a stroke missed than are adults over 75 years of age. This is especially the case for younger people with posterior circulation infarcts. Some medical centers have used hyperacute MRI in experimental studies for persons initially thought to have a low likelihood of stroke. And in some of these persons, strokes have been found which were then treated with thrombolytic medication.Prevention
Given the disease burden of strokes, prevention is an importantRisk factors
The most important modifiable risk factors for stroke are high blood pressure and atrial fibrillation although the size of the effect is small; 833 people have to be treated for 1 year to prevent one stroke. Other modifiable risk factors include high blood cholesterol levels,Blood pressure
Blood lipids
High cholesterol levels have been inconsistently associated with (ischemic) stroke.Diabetes mellitus
Anticoagulation drugs
Oral anticoagulants such asSurgery
Carotid endarterectomy or carotid angioplasty can be used to remove atherosclerotic narrowing of theDiet
Nutrition, specifically the Mediterranean-style diet, has the potential for decreasing the risk of having a stroke by more than half. It does not appear that lowering levels of homocysteine withWomen
A number of specific recommendations have been made for women including taking aspirin after the 11th week of pregnancy if there is a history of previous chronic high blood pressure and taking blood pressure medications during pregnancy if the blood pressure is greater than 150 mmHg systolic or greater than 100 mmHg diastolic. In those who have previously hadPrevious stroke or TIA
Keeping blood pressure below 140/90 mmHg is recommended. Anticoagulation can prevent recurrent ischemic strokes. Among people with nonvalvular atrial fibrillation, anticoagulation can reduce stroke by 60% while antiplatelet agents can reduce stroke by 20%. However, a recent meta-analysis suggests harm from anticoagulation started early after an embolic stroke. Stroke prevention treatment for atrial fibrillation is determined according to theManagement
Ischemic stroke
Aspirin reduces the overall risk of recurrence by 13% with greater benefit early on. Definitive therapy within the first few hours is aimed at removing the blockage by breaking the clot down ( thrombolysis), or by removing it mechanically ( thrombectomy). The philosophical premise underlying the importance of rapid stroke intervention was summed up as ''Time is Brain!'' in the early 1990s. Years later, that same idea, that rapid cerebral blood flow restoration results in fewer brain cells dying, has been proved and quantified. Tight blood sugar control in the first few hours does not improve outcomes and may cause harm. High blood pressure is also not typically lowered as this has not been found to be helpful. Cerebrolysin, a mixture of pig-derived neurotrophic factors used to treat acute ischemic stroke in many Asian and European countries, does not improve outcomes and may increase the risk of severe adverse events.Thrombolysis
Thrombolysis, such as with recombinant tissue plasminogen activator (rtPA), in acute ischemic stroke, when given within three hours of symptom onset, results in an overall benefit of 10% with respect to living without disability. It does not, however, improve chances of survival. Benefit is greater the earlier it is used. Between three and four and a half hours the effects are less clear. The AHA/ASA recommend it for certain people in this time frame. A 2014 review found a 5% increase in the number of people living without disability at three to six months; however, there was a 2% increased risk of death in the short term. After four and a half hours thrombolysis worsens outcomes. These benefits or lack of benefits occurred regardless of the age of the person treated. There is no reliable way to determine who will have an intracranial bleed post-treatment versus who will not. In those with findings of savable tissue on medical imaging between 4.5 hours and 9 hours or who wake up with a stroke, alteplase results in some benefit. Its use is endorsed by theEndovascular treatment
Mechanical removal of the blood clot causing the ischemic stroke, called mechanical thrombectomy, is a potential treatment for occlusion of a large artery, such as theCraniectomy
Strokes affecting large portions of the brain can cause significant brain swelling with secondary brain injury in surrounding tissue. This phenomenon is mainly encountered in strokes affecting brain tissue dependent upon the middle cerebral artery for blood supply and is also called "malignant cerebral infarction" because it carries a dismal prognosis. Relief of the pressure may be attempted with medication, but some requireHemorrhagic stroke
People withStroke unit
Ideally, people who have had a stroke are admitted to a "stroke unit", a ward or dedicated area in a hospital staffed by nurses and therapists with experience in stroke treatment. It has been shown that people admitted to a stroke unit have a higher chance of surviving than those admitted elsewhere in hospital, even if they are being cared for by doctors without experience in stroke.Rehabilitation
Spatial neglect
The current body of evidence is uncertain on the efficacy of cognitive rehabilitation for reducing the disabling effects of neglect and increasing independence remains unproven. However, there is limited evidence that cognitive rehabilitation may have an immediate beneficial effect on tests of neglect. Overall, no rehabilitation approach can be supported by evidence for spatial neglect.Automobile driving
The current body of evidence is uncertain whether the use of rehabilitation can improve on-road driving skills following stroke. There is limited evidence that training on a driving simulator will improve performance on recognizing road signs after training. The findings are based on low-quality evidence as further research is needed involving large numbers of participants.Yoga
Based on low quality evidence, it is currently uncertain whether yoga has a significant benefit for stroke rehabilitation on measures of quality of life, balance, strength, endurance, pain, and disability scores. Yoga may reduce anxiety and could be included as part of patient-centred stroke rehabilitation. Further research is needed assessing the benefits and safety of yoga in stroke rehabilitation.Action observation for upper limbs
The latest scientific evidence indicates that action observation is beneficial in improving upper limb motor function and dependence in activities of daily living in patients with stroke. Thus, action observation therapy is generally associated with better arm and hand function, with no significant adverse events. The findings are based on low to moderate quality evidence.Cognitive rehabilitation for attention deficits
The current body of scientific evidence is uncertain on the effectiveness of cognitive rehabilitation for attention deficits in patients following stroke. While there may be an immediate effect after treatment on attention, the findings are based on low to moderate quality and small number of studies. Further research is needed to assess whether the effect can be sustained in day-to-day tasks requiring attention.Motor imagery for gait rehabilitation
The latest evidence supports the short-term benefits of motor imagery (MI) on walking speed in individuals who have had a stroke, in comparison to other therapies. MI does not improve motor function after stroke and does not seem to cause significant adverse events. The findings are based on low-quality evidence as further research is needed to estimate the effect of MI on walking endurance and the dependence on personal assistance.Physical and occupational therapy
Physical and occupational therapy have overlapping areas of expertise; however, physical therapy focuses on joint range of motion and strength by performing exercises and relearning functional tasks such as bed mobility, transferring, walking and other gross motor functions. Physiotherapists can also work with people who have had a stroke to improve awareness and use of the hemiplegic side. Rehabilitation involves working on the ability to produce strong movements or the ability to perform tasks using normal patterns. Emphasis is often concentrated on functional tasks and people's goals. One example physiotherapists employ to promote motor learning involves= Interventions for age-related visual problems in patients with stroke
= With the prevalence of vision problems increasing with age in stroke patients, the overall effect of interventions for age-related visual problems is currently uncertain. It is also not sure whether people with stroke respond differently from the general population when treating eye problems. Further research in this area is needed as current body of evidence is very low quality.Speech and language therapy
Speech and language therapy is appropriate for people with the speech production disorders:Physical fitness
A stroke can also reduce people's general fitness. Reduced fitness can reduce capacity for rehabilitation as well as general health. Physical exercises as part of a rehabilitation program following a stroke appear safe. Cardiorespiratory fitness training that involves walking in rehabilitation can improve speed, tolerance and independence during walking, and may improve balance. There are inadequate long-term data about the effects of exercise and training on death, dependence and disability after a stroke. The future areas of research may concentrate on the optimal exercise prescription and long-term health benefits of exercise. The effect of physical training on cognition also may be studied further. The ability to walk independently in their community, indoors or outdoors, is important following stroke. Although no negative effects have been reported, it is unclear if outcomes can improve with these walking programs when compared to usual treatment.Other therapy methods
Some current and future therapy methods include the use ofOrthotics
Clinical studies confirm the importance of orthoses in stroke rehabilitation. The orthosis supports the therapeutic applications and also helps to mobilize the patient at an early stage. With the help of an orthosis, physiological standing and walking can be learned again, and late health consequences caused by a wrong gait pattern can be prevented. A treatment with an orthosis can therefore be used to support the therapy.Self-management
A stroke can affect the ability to live independently and with quality. Self-management programs are a special training that educates stroke survivors about stroke and its consequences, helps them acquire skills to cope with their challenges, and helps them set and meet their own goals during their recovery process. These programs are tailored to the target audience, and led by someone trained and expert in stroke and its consequences (most commonly professionals, but also stroke survivors and peers). A 2016 review reported that these programs improve the quality of life after stroke, without negative effects. People with stroke felt more empowered, happy and satisfied with life after participating in this training.Prognosis
Disability affects 75% of stroke survivors enough to decrease their ability to work. Stroke can affect people physically, mentally, emotionally, or a combination of the three. The results of stroke vary widely depending on size and location of the lesion.Physical effects
Some of the physical disabilities that can result from stroke include muscle weakness, numbness, pressure sores,Emotional and mental effects
Emotional and mental dysfunctions correspond to areas in the brain that have been damaged. Emotional problems following a stroke can be due to direct damage to emotional centers in the brain or from frustration and difficulty adapting to new limitations. Post-stroke emotional difficulties includeEpidemiology
Stroke was the second most frequent cause of death worldwide in 2011, accounting for 6.2 million deaths (~11% of the total). Approximately 17 million people had a stroke in 2010 and 33 million people have previously had a stroke and were still alive. Between 1990 and 2010 the number of strokes decreased by approximately 10% in the developed world and increased by 10% in the developing world. Overall, two-thirds of strokes occurred in those over 65 years old. South Asians are at particularly high risk of stroke, accounting for 40% of global stroke deaths. Incidence of ischemic stroke is ten times more frequent than haemorrhagic stroke. It is ranked after heart disease and before cancer. In the United States stroke is a leading cause of disability, and recently declined from the third leading to the fourth leading cause of death. Geographic disparities in stroke incidence have been observed, including the existence of a " stroke belt" in theHistory
Episodes of stroke and familial stroke have been reported from the 2nd millennium BC onward in ancient Mesopotamia and Persia.Research
As of 2017, angioplasty and stents were under preliminarySee also
* Cerebrovascular disease * Dejerine–Roussy syndrome *