A stroke is a

medical condition A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

in which poor

blood flow Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously m ...

to the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...

causes

cell death Cell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as d ...

. There are two main types of stroke:

ischemic Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems w ...

, due to lack of blood flow, and

hemorrhagic Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

, due to

bleeding Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

. Both cause parts of the brain to stop functioning properly. Signs and symptoms of a stroke may include an inability to move or feel on one side of the body, problems understanding or

speaking Speech is a human vocal communication using language. Each language uses phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if they are th ...

dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...

, or loss of vision to one side. Signs and symptoms often appear soon after the stroke has occurred. If symptoms last less than one or two hours, the stroke is a

transient ischemic attack A transient ischemic attack (TIA), commonly known as a mini-stroke, is a minor stroke whose noticeable symptoms usually end in less than an hour. TIA causes the same symptoms associated with strokes, such as weakness or numbness on one side of ...

(TIA), also called a mini-stroke. A hemorrhagic stroke may also be associated with a severe headache. The symptoms of a stroke can be permanent. Long-term complications may include

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...

and loss of bladder control. The main

risk factor In epidemiology, a risk factor or determinant is a variable associated with an increased risk of disease or infection. Due to a lack of harmonization across disciplines, determinant, in its more widely accepted scientific meaning, is often ...

for stroke is high blood pressure. Other risk factors include high blood cholesterol,

tobacco smoking Tobacco smoking is the practice of burning tobacco and ingesting the resulting smoke. The smoke may be inhaled, as is done with cigarettes, or simply released from the mouth, as is generally done with pipes and cigars. The practice is believed ...

obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

, a previous TIA,

end-stage kidney disease Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, vo ...

, and atrial fibrillation. An ischemic stroke is typically caused by blockage of a blood vessel, though there are also less common causes. A hemorrhagic stroke is caused by either bleeding directly into the brain or into the

space Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually cons ...

between the brain's membranes. Bleeding may occur due to a ruptured

brain aneurysm An intracranial aneurysm, also known as a brain aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel. Aneurysms in the posterior circ ...

. Diagnosis is typically based on a

physical exam In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions about the patie ...

and supported by medical imaging such as a CT scan or

MRI scan Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves ...

. A CT scan can rule out bleeding, but may not necessarily rule out ischemia, which early on typically does not show up on a CT scan. Other tests such as an electrocardiogram (ECG) and blood tests are done to determine risk factors and rule out other possible causes.

Low blood sugar Hypoglycemia, also called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's triad is used to properly identify hypoglycemic episodes. It is defined as blood glucose bel ...

may cause similar symptoms. Prevention includes decreasing risk factors, surgery to open up the arteries to the brain in those with problematic carotid narrowing, and

warfarin Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pulmonary embolism, and to prevent st ...

in people with atrial fibrillation.

Aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...

statin Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low ...

s may be recommended by physicians for prevention. A stroke or TIA often requires emergency care. An ischemic stroke, if detected within three to four and half hours, may be treatable with a

medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and ...

that can break down the clot. Some hemorrhagic strokes benefit from surgery. Treatment to attempt recovery of lost function is called stroke rehabilitation, and ideally takes place in a stroke unit; however, these are not available in much of the world. In 2013, approximately 6.9 million people had an ischemic stroke and 3.4 million people had a hemorrhagic stroke. In 2015, there were about 42.4 million people who had previously had a stroke and were still alive. Between 1990 and 2010 the number of strokes which occurred each year decreased by approximately 10% in the

developed world A developed country (or industrialized country, high-income country, more economically developed country (MEDC), advanced country) is a sovereign state that has a high quality of life, developed economy and advanced technological infrastruct ...

and increased by 10% in the developing world. In 2015, stroke was the second most frequent cause of death after coronary artery disease, accounting for 6.3 million deaths (11% of the total). About 3.0 million deaths resulted from ischemic stroke while 3.3 million deaths resulted from hemorrhagic stroke. About half of people who have had a stroke live less than one year. Overall, two thirds of strokes occurred in those over 65 years old.

Classification

Strokes can be classified into two major categories:

and

. Ischemic strokes are caused by interruption of the blood supply to the brain, while hemorrhagic strokes result from the rupture of a

blood vessel The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away ...

or an abnormal vascular structure. About 87% of strokes are ischemic, the rest being hemorrhagic. Bleeding can develop inside areas of ischemia, a condition known as "hemorrhagic transformation." It is unknown how many hemorrhagic strokes actually start as ischemic strokes.

Definition

In the 1970s the

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...

defined stroke as a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours", although the word "stroke" is centuries old. 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. The 24-hour limit divides stroke from

, which is a related syndrome of stroke symptoms that resolve completely within 24 hours. With the availability of treatments that can reduce stroke severity when given early, many now prefer alternative terminology, such as brain attack and acute ischemic cerebrovascular syndrome (modeled after

heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...

and acute coronary syndrome, respectively), to reflect the urgency of stroke symptoms and the need to act swiftly.

Ischemic

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: #

Thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (t ...

(obstruction of a blood vessel by a blood clot forming locally) #

Embolism An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule (fat embolism), a bubble of air or other gas ( gas embolism), amniotic fluid (am ...

(obstruction due to an

embolus An embolus (; plural emboli; from the Greek ἔμβολος "wedge", "plug") is an unattached mass that travels through the bloodstream and is capable of creating blockages. When an embolus occludes a blood vessel, it is called an embolism or emb ...

from elsewhere in the body), # Systemic hypoperfusion (general decrease in blood supply, e.g., in

shock Shock may refer to: Common uses Collective noun *Shock, a historic commercial term for a group of 60, see English numerals#Special names * Stook, or shock of grain, stacked sheaves Healthcare * Shock (circulatory), circulatory medical emergen ...

) # Cerebral venous sinus thrombosis. A stroke without an obvious explanation is termed cryptogenic (of unknown origin); this constitutes 30–40% of all ischemic strokes. There are various classification systems for acute ischemic stroke. The Oxford Community Stroke Project classification (OCSP, also known as the Bamford or Oxford classification) relies primarily on the initial symptoms; based on the extent of the symptoms, the stroke episode is classified as total anterior circulation infarct (TACI),

partial anterior circulation infarct Partial anterior circulation infarct (PACI) is a type of cerebral infarction affecting part of the anterior circulation supplying one side of the brain. Partial anterior circulation stroke syndrome (PACS) refers to the symptoms of a patient who c ...

(PACI),

lacunar infarct Lacunar stroke or lacunar cerebral infarct (LACI) is the most common type of ischemic stroke, resulting from the occlusion of small penetrating arteries that provide blood to the brain's deep structures. Patients who present with symptoms of a lac ...

(LACI) or

posterior circulation infarct Posterior circulation infarct (POCI) is a type of cerebral infarction affecting the posterior circulation supplying one side of the brain. Posterior circulation stroke syndrome (POCS) refers to the symptoms of a patient who clinically appears t ...

(POCI). These four entities predict the extent of the stroke, the area of the brain that is affected, the underlying cause, and the prognosis. The TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification is based on clinical symptoms as well as results of further investigations; on this basis, a stroke is classified as being due to (1) thrombosis or embolism due to

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no s ...

of a large artery, (2) an embolism originating in the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...

, (3) complete blockage of a small blood vessel, (4) other determined cause, (5) undetermined cause (two possible causes, no cause identified, or incomplete investigation).

Users Ancient Egyptian roles * User (ancient Egyptian official), an ancient Egyptian nomarch (governor) of the Eighth Dynasty * Useramen, an ancient Egyptian vizier also called "User" Other uses * User (computing) A user is a person who ...

of stimulants such as

cocaine Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Ameri ...

and methamphetamine are at a high risk for ischemic strokes.

Hemorrhagic

There are two main types of hemorrhagic stroke: * Intracerebral hemorrhage, which is basically bleeding within the brain itself (when an artery in the brain bursts, flooding the surrounding tissue with blood), due to either

intraparenchymal hemorrhage Intraparenchymal hemorrhage (IPH) is one form of intracerebral bleeding in which there is bleeding within brain parenchyma. The other form is intraventricular hemorrhage (IVH). Intraparenchymal hemorrhage accounts for approximately 8-13% of al ...

(bleeding within the brain tissue) or

intraventricular hemorrhage Intraventricular hemorrhage (IVH), also known as intraventricular bleeding, is a bleeding into the brain's ventricular system, where the cerebrospinal fluid is produced and circulates through towards the subarachnoid space. It can result from phys ...

(bleeding within the brain's

ventricular system The ventricular system is a set of four interconnected cavities known as cerebral ventricles in the brain. Within each ventricle is a region of choroid plexus which produces the circulating cerebrospinal fluid (CSF). The ventricular system is co ...

). * Subarachnoid hemorrhage, which is basically bleeding that occurs outside of the brain tissue but still within the skull, and precisely between the arachnoid mater and

pia mater Pia mater ( or ),Entry "pia mater"
in
meninges that surround the brain). The above two main types of hemorrhagic stroke are also two different forms of

intracranial hemorrhage Intracranial hemorrhage (ICH), also known as intracranial bleed, is hemorrhage, bleeding internal bleeding, within the Human skull, skull. Subtypes are intracerebral bleeds (intraventricular bleeds and intraparenchymal bleeds), subarachnoid bleed ...

, which is the accumulation of blood anywhere within the

cranial vault The cranial vault is the space in the skull within the neurocranium, occupied by the brain. Development In humans, the cranial vault is imperfectly composed in newborns, to allow the large human head to pass through the birth canal. During bi ...

; but the other forms of intracranial hemorrhage, such as

epidural hematoma Epidural hematoma is when bleeding occurs between the tough outer membrane covering the brain (dura mater) and the skull. Often there is loss of consciousness following a head injury, a brief regaining of consciousness, and then loss of consciou ...

(bleeding between the skull and the

dura mater In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. ...

, which is the thick ''outermost'' layer of the meninges that surround the brain) and

subdural hematoma A subdural hematoma (SDH) is a type of bleeding in which a collection of blood—usually but not always associated with a traumatic brain injury—gathers between the inner layer of the dura mater and the arachnoid mater of the meninges surround ...

(bleeding in the

subdural space The subdural space (or subdural cavity) is a potential space that can be opened by the separation of the arachnoid mater from the dura mater as the result of trauma, pathologic process, or the absence of cerebrospinal fluid as seen in a cadaver. ...

), are not considered "hemorrhagic strokes". Hemorrhagic strokes may occur on the background of alterations to the blood vessels in the brain, such as

cerebral amyloid angiopathy Cerebral amyloid angiopathy (CAA) is a form of angiopathy in which amyloid beta peptide deposits in the walls of small to medium blood vessels of the central nervous system and meninges. The term ''congophilic'' is sometimes used because the pre ...

cerebral arteriovenous malformation A cerebral arteriovenous malformation (cerebral AVM, CAVM, cAVM) is an abnormal connection between the arteries and veins in the brain—specifically, an arteriovenous malformation in the cerebrum. Signs and symptoms The most frequently observed ...

and an

intracranial aneurysm An intracranial aneurysm, also known as a brain aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel. Aneurysms in the posterior circula ...

, which can cause intraparenchymal or subarachnoid hemorrhage. In addition to neurological impairment, hemorrhagic strokes usually cause specific symptoms (for instance, subarachnoid hemorrhage classically causes a severe headache known as a

thunderclap headache A thunderclap headache is a headache that is severe and has a sudden onset. It is defined as a severe headache that takes seconds to minutes to reach maximum intensity. Although approximately 75% are attributed to "primary" headaches—headache d ...

) or reveal evidence of a previous

head injury A head injury is any injury that results in trauma to the skull or brain. The terms ''traumatic brain injury'' and ''head injury'' are often used interchangeably in the medical literature. Because head injuries cover such a broad scope of inju ...

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 a headache, apart from subarachnoid hemorrhage and cerebral venous thrombosis and occasionally intracerebral hemorrhage.

Early 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 The likelihood function (often simply called the likelihood) represents the probability of random variable realizations conditional on particular values of the statistical parameters. Thus, when evaluated on a given sample, the likelihood functi ...

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 is FAST (facial droop, arm weakness, speech difficulty, and time to call emergency services), as advocated by the

Department of Health (United Kingdom) The Department of Health and Social Care (DHSC) is a department of His Majesty's Government responsible for government policy on health and adult social care matters in England, along with a few elements of the same matters which are not otherwis ...

and the Stroke Association, the

American Stroke Association The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and death ...

, the National Stroke Association (US), the

Los Angeles Prehospital Stroke Screen (LAPSS) The Los Angeles Prehospital Stroke Screen (abbreviated LAPSS) is a method of identifying potential stroke patients in a pre-hospital setting. Screening criteria * No history of seizures or epilepsy *Age 45 years or older *At baseline, patient is ...

and the

Cincinnati Prehospital Stroke Scale The Cincinnati Prehospital Stroke Scale (abbreviated CPSS) is a system used to diagnose a potential stroke in a prehospital setting. It tests three signs for abnormal findings which may indicate that the patient is having a stroke. If any one of ...

(CPSS). Use of these scales is recommended by professional guidelines. FAST is less reliable in the recognition of posterior circulation strokes. For people referred to the emergency room, early recognition of stroke is deemed important as this can expedite diagnostic tests and treatments. A scoring system called ROSIER (recognition of stroke in the emergency room) is recommended for this purpose; it is based on features from the medical history and physical examination.

Subtypes

If the area of the brain affected includes one of the three prominent

central nervous system pathways Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

—the

spinothalamic tract The spinothalamic tract is a part of the anterolateral system or the ventrolateral system, a sensory pathway to the thalamus. From the ventral posterolateral nucleus in the thalamus, sensory information is relayed upward to the somatosensory co ...

corticospinal tract The corticospinal tract is a white matter motor pathway starting at the cerebral cortex that terminates on lower motor neurons and interneurons in the spinal cord, controlling movements of the limbs and trunk. There are more than one million neur ...

, and the

dorsal column–medial lemniscus pathway The dorsal column–medial lemniscus pathway (DCML) (also known as the posterior column-medial lemniscus pathway, PCML) is a sensory pathway of the central nervous system that conveys sensations of fine touch, vibration, two-point discriminatio ...

, symptoms may include: * hemiplegia and muscle weakness of the face * numbness * reduction in sensory or vibratory sensation * initial flaccidity (reduced muscle tone), replaced by

spasticity Spasticity () is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles ...

(increased muscle tone), excessive reflexes, and obligatory synergies. In most cases, the symptoms affect only one side of the body (unilateral). Depending on the part of the brain affected, the defect in the brain is ''usually'' on the opposite side of the body. However, since these pathways also travel in the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...

and any lesion there can also produce these symptoms, the presence of any one of these symptoms does not necessarily indicate a stroke. In addition to the above CNS pathways, the '' brainstem'' gives rise to most of the twelve

cranial nerves Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and f ...

. A brainstem stroke affecting the brainstem and brain, therefore, can produce symptoms relating to deficits in these cranial nerves: * altered smell, taste, hearing, or vision (total or partial) * drooping of eyelid ( ptosis) and weakness of

ocular muscles The extraocular muscles (extrinsic ocular muscles), are the seven extrinsic muscles of the human eye. Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye and the othe ...

* decreased reflexes: gag, swallow, pupil reactivity to light * decreased sensation and muscle weakness of the face * balance problems and

nystagmus Nystagmus is a condition of involuntary (or voluntary, in some cases) eye movement. Infants can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in reduced or limited vision. Due to the invol ...

* altered breathing and heart rate * weakness in

sternocleidomastoid muscle The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the access ...

with inability to turn head to one side * weakness in tongue (inability to stick out the tongue or move it from side to side) If the ''

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consistin ...

'' is involved, the CNS pathways can again be affected, but also can produce the following symptoms: *

aphasia Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in t ...

(difficulty with verbal expression, auditory comprehension,

reading Reading is the process of taking in the sense or meaning of letters, symbols, etc., especially by sight or touch. For educators and researchers, reading is a multifaceted process involving such areas as word recognition, orthography (spelling ...

and

writing Writing is a medium of human communication which involves the representation of a language through a system of physically inscribed, mechanically transferred, or digitally represented symbols. Writing systems do not themselves constitute h ...

; Broca's or

Wernicke's area Wernicke's area (; ), also called Wernicke's speech area, is one of the two parts of the cerebral cortex that are linked to speech, the other being Broca's area. It is involved in the comprehension of written and spoken language, in contrast to B ...

typically involved) *

dysarthria Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. In other words, it is a condition in which problems effectively ...

(

motor speech disorder Motor speech disorders are a class of speech disorders that disturb the body's natural ability to speak due to neurologic impairments. These neurologic impairments make it difficult for individuals with motor speech disorders to plan, program, co ...

resulting from neurological injury) *

apraxia Apraxia is a motor disorder caused by damage to the brain (specifically the posterior parietal cortex or corpus callosum), which causes difficulty with motor planning to perform tasks or movements. The nature of the damage determines the disorde ...

(altered voluntary movements) *

visual field The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments". Or simply, visual field can be defined as the entire area that can be seen when an eye is fixed straight at a point ...

defect * memory deficits (involvement of

temporal lobe The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved in pro ...

) *

hemineglect Hemispatial neglect is a neuropsychological condition in which, after damage to one hemisphere of the brain (e.g. after a stroke), a deficit in attention and awareness towards the side of space opposite brain damage (contralesional space) is obse ...

(involvement of

parietal lobe The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integrates sensory informa ...

) * disorganized thinking, confusion,

hypersexual Hypersexuality is extremely frequent or suddenly increased libido. It is controversial whether it should be included as a clinical diagnosis used by mental healthcare professionals. Nymphomania and satyriasis were terms previously used for the c ...

gestures (with involvement of frontal lobe) * lack of insight of his or her, usually stroke-related, disability If the '' cerebellum'' is involved,

ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...

might be present and this includes: * altered walking gait * altered movement coordination *

vertigo Vertigo is a condition where a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties w ...

and or disequilibrium

Associated symptoms

Loss of consciousness Loss may refer to: Arts, entertainment, and media Music * ''Loss'' (Bass Communion album) (2006) * ''Loss'' (Mull Historical Society album) (2001) *"Loss", a song by God Is an Astronaut from their self-titled album (2008) * Losses "(Lil Tjay son ...

, headache, and vomiting usually occur more often in hemorrhagic stroke than in thrombosis because of the increased

intracranial pressure Intracranial pressure (ICP) is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue. ICP is measured in millimeters of mercury ( mmHg) and at rest, is normally 7–15 mmHg for a supine adult ...

from the leaking blood compressing the brain. If symptoms are maximal at onset, the cause is more likely to be a subarachnoid hemorrhage or an embolic stroke.

Causes

Thrombotic stroke

In thrombotic stroke, a thrombus (blood clot) usually forms around

atherosclerotic Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no ...

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

. Two types of thrombosis can cause stroke: * ''Large vessel disease'' involves the common and

internal carotid arteries The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these ...

, the

vertebral artery The vertebral arteries are major arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline ba ...

, and the

Circle of Willis The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a circulatory anastomosis that supplies blood to the brain and surrounding structures in reptiles, birds and mammals, including huma ...

. Diseases that may form

thrombi A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of cr ...

in the large vessels include (in descending incidence): atherosclerosis,

vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vess ...

(tightening of the artery), aortic,

carotid In anatomy, the left and right common carotid arteries (carotids) (Entry "carotid"
in
vertebral artery dissection Vertebral artery dissection (VAD) is a flap-like tear of the inner lining of the vertebral artery, which is located in the neck and supplies blood to the brain. After the tear, blood enters the arterial wall and forms a blood clot, thickening t ...

, various inflammatory diseases of the blood vessel wall (

Takayasu arteritis Takayasu's arteritis (TA), also known as aortic arch syndrome, nonspecific aortoarteritis, and pulseless disease, is a form of large vessel granulomatous vasculitisAmerican College of Physicians (ACP). Medical Knowledge Self-Assessment Program (MK ...

giant cell arteritis Giant cell arteritis (GCA), also called temporal arteritis, is an inflammatory autoimmune disease of large blood vessels. Symptoms may include headache, pain over the temples, flu-like symptoms, double vision, and difficulty opening the mouth. ...

vasculitis Vasculitis is a group of disorders that destroy blood vessels by inflammation. Both arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis. Vasculitis is primarily caused ...

), noninflammatory vasculopathy,

Moyamoya disease Moyamoya disease is a disease in which certain arteries in the brain are constricted. Blood flow is blocked by constriction and blood clots (thrombosis). A collateral circulation develops around the blocked vessels to compensate for the blockage, ...

and

fibromuscular dysplasia Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory disease of the blood vessels that causes abnormal growth within the wall of an artery. FMD has been found in nearly every arterial bed in the body although the most common ...

. * ''

Small vessel disease Microangiopathy (also known as microvascular disease, small vessel disease (SVD) or microvascular dysfunction) is a disease of the microvessels, small blood vessels in the microcirculation. It can be contrasted to coronary heart disease, an angio ...

'' involves the smaller arteries inside the brain: branches of the

circle of Willis The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a circulatory anastomosis that supplies blood to the brain and surrounding structures in reptiles, birds and mammals, including huma ...

, middle cerebral artery, stem, and arteries arising from the distal vertebral and

basilar artery The basilar artery () is one of the arteries that supplies the brain with oxygen-rich blood. The two vertebral arteries and the basilar artery are known as the vertebral basilar system, which supplies blood to the posterior part of the circle of W ...

. Diseases that may form thrombi in the small vessels include (in descending incidence):

lipohyalinosis Lipohyalinosis is a cerebral small vessel disease affecting the small arteries, arterioles or capillaries in the brain. Originally defined by C. Miller Fisher as 'segmental arteriolar wall disorganisation', it is characterized by vessel wall thick ...

(build-up of fatty hyaline matter in the blood vessel as a result of high blood pressure and aging) and

fibrinoid degeneration Fibrinoid necrosis is a specific pattern of irreversible, uncontrolled cell death that occurs when antigen-antibody complexes are deposited in the walls of blood vessels along with fibrin. It is common in the immune-mediated vasculitides which a ...

(a stroke involving these vessels is known as a

lacunar stroke Lacunar stroke or lacunar cerebral infarct (LACI) is the most common type of ischemic stroke, resulting from the occlusion of small penetrating arteries that provide blood to the brain's deep structures. Patients who present with symptoms of a lac ...

) and microatheroma (small atherosclerotic plaques). Anemia causes increase blood flow in the blood circulatory system. This causes the endothelial cells of the blood vessels to express adhesion factors which encourages the clotting of blood and formation of thrombus.

Sickle-cell anemia Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red bl ...

, which can cause

blood cell A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes) ...

s to clump up and block blood vessels, can also lead to stroke. A stroke is the second leading cause of death in people under 20 with sickle-cell anemia.

Air pollution Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different typ ...

may also increase stroke risk.

Embolic stroke

An embolic stroke refers to an arterial embolism (a blockage of an artery) by an

, 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 In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple est ...

(e.g., from bone marrow in a

broken bone A bone fracture (abbreviated FRX or Fx, Fx, or #) is a medical condition in which there is a partial or complete break in the continuity of any bone in the body. In more severe cases, the bone may be broken into several fragments, known as a '' ...

), air,

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

cells or clumps of

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

(usually from infectious

endocarditis Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or the ...

). Because an embolus arises from elsewhere, local therapy solves the problem only temporarily. Thus, the source of the embolus must be identified. Because the embolic blockage is sudden in onset, symptoms usually are maximal at the start. Also, symptoms may be transient as the embolus is partially resorbed and moves to a different location or dissipates altogether. Emboli most commonly arise from the

(especially in atrial fibrillation) but may originate from elsewhere in the arterial tree. In

paradoxical embolism An embolus, is described as a free-floating mass, located inside blood vessels that can travel from one site in the blood stream to another. An embolus can be made up of solid (like a blood clot), liquid (like amniotic fluid), or gas (like air). O ...

, a

deep vein thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...

embolizes through an

atrial The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves. There are two at ...

ventricular septal defect A ventricular septal defect (VSD) is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart. The extent of the opening may vary from pin size to complete absence of the ventricular septum, creating one ...

in the heart into the brain. Causes of stroke related to the heart can be distinguished between high and low-risk: * High risk: atrial fibrillation and paroxysmal atrial fibrillation,

rheumatic disease Rheumatism or rheumatic disorders are conditions causing chronic, often intermittent pain affecting the joints or connective tissue. Rheumatism does not designate any specific disorder, but covers at least 200 different conditions, including art ...

of the

mitral The mitral valve (), also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. It has two cusps or flaps and lies between the left atrium and the left ventricle of the heart. The heart valves are all one-w ...

aortic valve The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. Th ...

disease,

artificial heart valve An artificial heart valve is a one-way valve implanted into a person's heart to replace a heart valve that is not functioning properly ( valvular heart disease). Artificial heart valves can be separated into three broad classes: mechanical he ...

s, known cardiac thrombus of the atrium or ventricle,

sick sinus syndrome Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms ( arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a varia ...

, sustained

atrial flutter Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart. When it first occurs, it is usually associated with a fast heart rate and is classified as a type of supraventricular tachycardia. Atrial f ...

, recent myocardial infarction, chronic myocardial infarction together with

ejection fraction An ejection fraction (EF) is the volumetric fraction (or portion of the total) of fluid (usually blood) ejected from a chamber (usually the heart) with each contraction (or heartbeat). It can refer to the cardiac atrium, ventricle, gall bladder, ...

<28 percent, symptomatic

congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

with ejection fraction <30 percent,

dilated cardiomyopathy Dilated cardiomyopathy (DCM) is a condition in which the heart becomes enlarged and cannot pump blood effectively. Symptoms vary from none to feeling tired, leg swelling, and shortness of breath. It may also result in chest pain or fainting. Co ...

, Libman-Sacks endocarditis, Marantic endocarditis,

infective endocarditis Infective endocarditis is an infection of the inner surface of the heart, usually the valves. Signs and symptoms may include fever, small areas of bleeding into the skin, heart murmur, feeling tired, and low red blood cell count. Complications ...

papillary fibroelastoma A papillary fibroelastoma is a primary tumor of the heart that typically involves one of the valves of the heart. Papillary fibroelastomas, while considered uncommon, make up about 10 percent of all primary tumors of the heart. They are the third ...

, left atrial myxoma and

coronary artery bypass graft Coronary artery bypass surgery, also known as coronary artery bypass graft (CABG, pronounced "cabbage") is a surgical procedure to treat coronary artery disease (CAD), the buildup of plaques in the arteries of the heart. It can relieve chest pai ...

(CABG) surgery. * 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 Mitral stenosis is a valvular heart disease characterized by the narrowing of the opening of the mitral valve of the heart. It is almost always caused by rheumatic valvular heart disease. Normally, the mitral valve is about 5 cm2 during d ...

or atrial fibrillation), complex atheroma in the ascending aorta or proximal arch. Among those who have a complete blockage of one of the carotid arteries, the risk of stroke on that side is about one percent per year. A special form of embolic stroke is the embolic stroke of undetermined source (ESUS). This subset of cryptogenic stroke is defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources. About one out of six ischemic strokes could be classified as ESUS.

Cerebral 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 to heart failure from

cardiac arrest Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and poss ...

or arrhythmias, or from reduced cardiac output as a result of

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...

, 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 vulnerable "watershed" areas—border zone regions supplied by the major cerebral arteries. A watershed stroke refers to the condition when the blood supply to these areas is compromised. Blood flow to these areas does not necessarily stop, but instead it may lessen to the point where brain damage can occur.

Venous thrombosis

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.

Intracerebral hemorrhage

It generally occurs in small arteries or arterioles and is commonly due to hypertension, intracranial vascular malformations (including cavernous angiomas or arteriovenous malformations), cerebral amyloid angiopathy, or infarcts into which secondary hemorrhage has occurred. Other potential causes are trauma, Hemophilia, bleeding disorders, amyloid angiopathy, Recreational drug use, illicit drug use (e.g., amphetamines or

). The hematoma enlarges until pressure from surrounding tissue limits its growth, or until it decompresses by emptying into the

, cerebrospinal fluid, CSF or the pial surface. 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 subarachnoid hemorrhage (which technically may also be classified as a type of stroke).

Other

Other causes may include spasm of an artery. This may occur due to

Silent 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

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 or hemorrhages. Silent strokes typically cause lesions which are detected via the use of neuroimaging such as MRI. Silent strokes are estimated to occur at five times the rate of symptomatic strokes. The risk of silent stroke increases with age, but may also affect younger adults and children, especially those with acute anemia.

Pathophysiology

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 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 atrial fibrillation, or in the carotid arteries, break off, enter the cerebral circulation, then lodge in and block brain blood vessels. Since blood vessels in the brain are now blocked, the brain becomes low in energy, and thus it resorts to using anaerobic metabolism within the region of brain tissue affected by ischemia. Anaerobic metabolism produces less adenosine triphosphate (ATP) but releases a by-product called lactic acid. Lactic acid is an irritant which could potentially destroy cells since it is an acid and disrupts the normal acid-base balance in the brain. The ischemia area is referred to as the "ischemic penumbra (medicine), penumbra". After the initial ischemic event the penumbra transitions from a tissue remodeling characterized by damage to a remodeling characterized by repair. 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 the 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⁺) 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, programmed cell death. Ischemia 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 may occur. 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.

Hemorrhagic

Hemorrhagic strokes are classified based on their underlying pathology. Some causes of hemorrhagic stroke are Hypertensive, hypertensive hemorrhage, ruptured aneurysm, ruptured AV fistula, transformation of prior ischemic infarction, and drug-induced

. They result in tissue injury by causing compression of tissue from an expanding hematoma or hematomas. 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. Inflammation contributes to the secondary brain injury after hemorrhage.

Diagnosis

Dens media sign mit Mediainfarkt - CCT 001

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 used blood test for the stroke diagnosis itself, though blood tests may be of help in finding out the likely cause of stroke. In deceased people, an autopsy of stroke may help establishing the time between stroke onset and death.

Physical examination

A physical examination, including taking a medical history of the symptoms and a neurological status, helps giving an evaluation of the location and severity of a stroke. It can give a standard score on e.g., the NIH stroke scale.

Imaging

For diagnosing ischemic (blockage) stroke in the emergency setting: * CT scans (''without'' contrast enhancements) : sensitivity (tests), sensitivity= 16% (less than 10% within first 3 hours of symptom onset) : specificity (tests), 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 (

). MRI is better at detecting a posterior circulation infarct with Diffusion MRI, diffusion-weighted imaging. A CT scan is used more to ''rule out'' certain stroke mimics and detect bleeding. The presence of leptomeningeal collateral circulation in the brain is associated with better clinical outcomes after recanalization treatment. Cerebrovascular reserve capacity is another factor that affects stroke outcome it is the amount of increase in cerebral blood flow after a purposeful stimulation of blood flow by the physician, such as by giving inhaled carbon dioxide or intravenous acetazolamide. The increase in blood flow can be measured by PET scan or transcranial doppler sonography. However, in people with obstruction of the internal carotid artery of one side, the presence of leptomeningeal collateral circulation is associated with reduced cerebral reserve capacity.

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, comorbidity and the clinical presentation. The following are commonly used techniques: * an medical ultrasonography, ultrasound/doppler study of the carotid artery, carotid arteries (to detect carotid stenosis) or dissection of the precerebral arteries; * 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); * a Holter monitor study to identify intermittent Heart arrhythmia, abnormal heart rhythms; * an angiogram of the cerebral vasculature (if a bleed is thought to have originated from an aneurysm or arteriovenous malformation); * blood tests to determine if hypercholesterolemia, blood cholesterol is high, if there is an abnormal bleeding diathesis, tendency to bleed, and if some rarer processes such as homocysteinuria, homocystinuria might be involved. For hemorrhagic strokes, a Computed tomography angiography, CT or Magnetic resonance angiography, MRI scan with intravascular contrast may be able to identify abnormalities in the brain arteries (such as aneurysms) or other sources of bleeding, and structural MRI if this shows no cause. If this too does not identify an underlying reason for the bleeding, invasive cerebral angiography could be performed but this requires access to the bloodstream with an intravascular catheter and can cause further strokes as well as complications at the insertion site and this investigation is therefore reserved for specific situations. If there are symptoms suggesting that the hemorrhage might have occurred as a result of cerebral venous sinus thrombosis, venous thrombosis, CT or MRI venography can be used to examine the cerebral veins.

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 (medical), prevention is an important public health concern. Primary prevention is less effective than secondary prevention (as judged by the number needed to treat to prevent one stroke per year). Recent guidelines detail the evidence for primary prevention in stroke. In those who are otherwise healthy, aspirin does not appear beneficial and thus is not recommended. In people who have had a myocardial infarction or those with a high cardiovascular risk, it provides some protection against a first stroke.NPS Prescribing Practice Review 44: Antiplatelets and anticoagulants in stroke prevention (2009). Available a
nps.org.au
In those who have previously had a stroke, treatment with medications such as aspirin, clopidogrel, and dipyridamole may be beneficial. The U.S. Preventive Services Task Force (USPSTF) recommends against Screening (medicine), screening for carotid artery stenosis in those without symptoms.

Risk 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,

, cigarette smoking (active and passive), heavy Alcohol consumption and health, alcohol use, drug use, lack of physical activity,

, processed red meat consumption, and unhealthy diet. Smoking just one cigarette per day increases the risk more than 30%. Alcohol use could predispose to ischemic stroke, as well as intracerebral and subarachnoid hemorrhage via multiple mechanisms (for example, via hypertension, atrial fibrillation, rebound thrombocytosis and platelet aggregation and clotting disturbances). Drugs, most commonly amphetamines and cocaine, can induce stroke through damage to the blood vessels in the brain and acute hypertension. Migraine with aura (symptom), aura doubles a person's risk for ischemic stroke. Untreated, celiac disease regardless of the presence of symptoms can be an underlying cause of stroke, both in children and adults. High levels of physical activity reduce the risk of stroke by about 26%. There is a lack of high quality studies looking at promotional efforts to improve lifestyle factors. Nonetheless, given the large body of circumstantial evidence, best medical management for stroke includes advice on diet, exercise, smoking and alcohol use. Medication is the most common method of stroke prevention; carotid endarterectomy can be a useful surgical method of preventing stroke.

Blood pressure

Hypertension, High blood pressure accounts for 35–50% of stroke risk. Blood pressure reduction of 10 mmHg systolic or 5 mmHg diastolic reduces the risk of stroke by ~40%. Lowering blood pressure has been conclusively shown to prevent both ischemic and hemorrhagic strokes. It is equally important in secondary prevention. Even people older than 80 years and those with isolated systolic hypertension benefit from antihypertensive therapy. The available evidence does not show large differences in stroke prevention between antihypertensive drugs—therefore, other factors such as protection against other forms of cardiovascular disease and cost should be considered. The routine use of beta-blockers following a stroke or TIA has not been shown to result in benefits.

Blood lipids

High cholesterol levels have been inconsistently associated with (ischemic) stroke. Statins have been shown to reduce the risk of stroke by about 15%. Since earlier meta-analyses of other lipid-lowering drugs did not show a decreased risk, statins might exert their effect through mechanisms other than their lipid-lowering effects.

Diabetes mellitus

Diabetes mellitus increases the risk of stroke by 2 to 3 times. While intensive blood sugar control has been shown to reduce small blood vessel complications such as Diabetic nephropathy, kidney damage and Diabetic retinopathy, damage to the retina of the eye it has not been shown to reduce large blood vessel complications such as stroke.

Anticoagulation drugs

Oral anticoagulants such as

have been the mainstay of stroke prevention for over 50 years. However, several studies have shown that aspirin and other antiplatelet drug, antiplatelets are highly effective in secondary prevention after a stroke or transient ischemic attack. Low doses of aspirin (for example 75–150 mg) are as effective as high doses but have fewer side effects; the lowest effective dose remains unknown. Thienopyridines (clopidogrel, ticlopidine) might be slightly more effective than aspirin and have a decreased risk of gastrointestinal bleeding, but are more expensive. Both aspirin and clopidogrel may be useful in the first few weeks after a minor stroke or high risk TIA. Clopidogrel has less side effects than ticlopidine. Dipyridamole can be added to aspirin therapy to provide a small additional benefit, even though headache is a common side effect. Low-dose aspirin is also effective for stroke prevention after having a myocardial infarction. Those with atrial fibrillation have a 5% a year risk of stroke, and this risk is higher in those with valvular atrial fibrillation. Depending on the stroke risk, anticoagulation with medications such as

or aspirin is useful for prevention. Except in people with atrial fibrillation, oral anticoagulants are not advised for stroke prevention—any benefit is offset by bleeding risk. In primary prevention, however, antiplatelet drugs did not reduce the risk of ischemic stroke but increased the risk of major bleeding. Further studies are needed to investigate a possible protective effect of aspirin against ischemic stroke in women.

Surgery

Carotid endarterectomy or carotid angioplasty can be used to remove atherosclerotic narrowing of the carotid artery. There is evidence supporting this procedure in selected cases. Endarterectomy for a significant stenosis has been shown to be useful in preventing further strokes in those who have already had one. Carotid artery stenting has not been shown to be equally useful. People are selected for surgery based on age, gender, degree of stenosis, time since symptoms and the person's preferences. Surgery is most efficient when not delayed too long—the risk of recurrent stroke in a person who has a 50% or greater stenosis is up to 20% after 5 years, but endarterectomy reduces this risk to around 5%. The number of procedures needed to cure one person was 5 for early surgery (within two weeks after the initial stroke), but 125 if delayed longer than 12 weeks. Screening (medicine), Screening for carotid artery narrowing has not been shown to be a useful test in the general population. Studies of surgical intervention for carotid artery stenosis without symptoms have shown only a small decrease in the risk of stroke. To be beneficial, the complication rate of the surgery should be kept below 4%. Even then, for 100 surgeries, 5 people will benefit by avoiding stroke, 3 will develop stroke despite surgery, 3 will develop stroke or die due to the surgery itself, and 89 will remain stroke-free but would also have done so without intervention.

Diet

Nutrition, specifically the Mediterranean diet, 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 with folic acid affects the risk of stroke.

Women

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 had preeclampsia other risk factors should be treated more aggressively.

Previous 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 the CHA2DS2–VASc score. The most widely used anticoagulant to prevent thromboembolic stroke in people with nonvalvular atrial fibrillation is the oral agent

while a number of newer agents including dabigatran are alternatives which do not require prothrombin time monitoring. Anticoagulants, when used following stroke, should not be stopped for dental procedures. If studies show carotid artery stenosis, and the person has a degree of residual function on the affected side, carotid endarterectomy (surgical removal of the stenosis) may decrease the risk of recurrence if performed rapidly after stroke.

Management

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 the American Heart Association, the American College of Emergency Physicians 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 no 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 which showed that tPA improves the chances for a good neurological outcome. When administered within the first three hours thrombolysis improves functional outcome without affecting mortality. 6.4% of people with large strokes developed substantial brain bleeding as a complication from being given tPA thus part of the reason for increased short term mortality. The American Academy of Emergency Medicine had previously stated that objective evidence regarding the applicability of tPA for acute ischemic stroke was insufficient. In 2013 the American College of Emergency Medicine refuted this position, acknowledging the body of evidence for the use of tPA in ischemic stroke; but debate continues. Intra-arterial fibrinolysis, where a catheter is passed up an artery into the brain and the medication is injected at the site of thrombosis, has been found to improve outcomes in people with acute ischemic stroke.

Endovascular treatment

Mechanical removal of the blood clot causing the ischemic stroke, called Thrombectomy, mechanical thrombectomy, is a potential treatment for occlusion of a large artery, such as the middle cerebral artery. In 2015, one review demonstrated the safety and efficacy of this procedure if performed within 12 hours of the onset of symptoms. It did not change the risk of death, but reduced disability compared to the use of intravenous thrombolysis which is generally used in people evaluated for mechanical thrombectomy. Certain cases may benefit from thrombectomy up to 24 hours after the onset of symptoms.

Craniectomy

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 require hemicraniectomy, the temporary surgical removal of the skull on one side of the head. This decreases the risk of death, although some people – who would otherwise have died – survive with disability.

Hemorrhagic stroke

People with intracerebral hemorrhage require supportive care, including blood pressure control if required. People are monitored for changes in the level of consciousness, and their blood sugar and oxygenation are kept at optimum levels. Anticoagulants and antithrombotics can make bleeding worse and are generally discontinued (and reversed if possible). A proportion may benefit from neurosurgery, neurosurgical intervention to remove the blood and treat the underlying cause, but this depends on the location and the size of the hemorrhage as well as patient-related factors, and ongoing research is being conducted into the question as to which people with intracerebral hemorrhage may benefit. In subarachnoid hemorrhage, early treatment for underlying cerebral aneurysms may reduce the risk of further hemorrhages. Depending on the site of the aneurysm this may be by craniotomy, surgery that involves opening the skull or Interventional neuroradiology, endovascularly (through the blood vessels).

Stroke 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. Nursing care is fundamental in maintaining Skin, skin care, feeding, hydration, positioning, and monitoring vital signs such as temperature, pulse, and blood pressure.

Rehabilitation

Stroke rehabilitation is the process by which those 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. Stroke rehabilitation should begin almost immediately with a multidisciplinary approach. The rehabilitation team may involve physicians trained in rehabilitation medicine, neurologists, clinical pharmacists, nursing staff, physiotherapists, occupational therapists, Speech-language pathology, speech-language pathologists, and orthotists. Some teams may also include psychologists and social workers, since at least one-third of affected people manifests post stroke depression. Validated instruments such as the Barthel scale may be used to assess the likelihood of a person who has had a stroke being able to manage at home with or without support subsequent to discharge from a hospital. Stroke rehabilitation should be started as quickly as possible and can last anywhere from a few days to over a year. Most return of function is seen in the first few months, 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, some people have reported that they 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 daily routine for people who have had a stroke. Complete recovery is unusual but not impossible and most people will improve to some extent: proper diet and exercise are known to help the brain to recover.

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 constraint-induced movement therapy. Through continuous practice the person relearns to use and adapt the hemiplegic limb during functional activities to create lasting permanent changes. Physical therapy is effective for recovery of function and mobility after stroke. Occupational therapy is involved in training to help relearn everyday activities known as the activities of daily living (ADLs) such as eating, drinking, dressing, bathing, cooking,

and agraphia, writing, and toileting. Approaches to helping people with urinary incontinence include physical therapy, cognitive therapy, and specialized interventions with experienced medical professionals, however, it is not clear how effective these approaches are at improving urinary incontinence following a stroke. Treatment of spasticity related to stroke often involves early mobilizations, commonly performed by a physiotherapist, combined with elongation of spastic muscles and sustained stretching through various different positions. Gaining initial improvement in range of motion is often achieved through rhythmic rotational patterns associated with the affected limb. After full range has been achieved by the therapist, the limb should be positioned in the lengthened positions to prevent against further contractures, skin breakdown, and disuse of the limb with the use of splints or other tools to stabilize the joint. Cold in the form of ice wraps or ice packs have been proven to briefly reduce spasticity by temporarily dampening neural firing rates. Sensory stimulation therapy#Coactivation, Electrical stimulation to the antagonist muscles or vibrations has also been used with some success. Physical therapy is sometimes suggested for people who experience sexual dysfunction following a stroke.

= 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:

and apraxia of speech,

, cognitive-communication impairments, and dysphagia, problems with swallowing. Speech and language therapy for aphasia following stroke compared to no therapy improves functional communication, reading, writing and expressive language. There may be benefit in high intensity and high doses over a longer period, but these higher intensity doses may not be acceptable to everyone. People who have had a stroke may have particular problems, such as dysphagia, 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 deemed unsafe, then a percutaneous endoscopic gastrostomy (PEG) tube is passed and this can remain indefinitely. Swallowing therapy has mixed results as of 2018.

Orthotics#Ankle–foot orthosis (AFO), Devices

Often, assistive technology such as wheelchairs, walkers and canes may be beneficial. Many mobility problems can be improved by the use of Orthotics#Ankle–foot orthosis (AFO), ankle foot orthoses.

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 of virtual reality and video games for rehabilitation. These forms of rehabilitation offer potential for motivating people to perform specific therapy tasks that many other forms do not. While virtual reality and interactive video gaming are not more effective than conventional therapy for improving upper limb function, when used in conjunction with usual care these approaches may improve upper limb function and ADL function. There are inadequate data on the effect of virtual reality and interactive video gaming on gait speed, balance, participation and quality of life. Many clinics and hospitals are adopting the use of these off-the-shelf devices for exercise, social interaction, and rehabilitation because they are affordable, accessible and can be used within the clinic and home. Mirror box, Mirror therapy is associated with improved motor function of the upper extremity in people who have had a stroke. Other non-invasive rehabilitation methods used to augment physical therapy of motor function in people recovering from a stroke include transcranial magnetic stimulation and transcranial direct-current stimulation. and Rehabilitation robotics, robotic therapies. Constraint‐induced movement therapy (CIMT), mental practice, mirror therapy, interventions for sensory impairment, virtual reality and a relatively high dose of repetitive task practice may be effective in improving upper limb function. However, further primary research, specifically of CIMT, mental practice, mirror therapy and virtual reality is needed.

Orthotics

Clinical studies confirm the importance of Orthotics, 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,

, Urinary incontinence, incontinence,

(inability to perform learned movements), difficulties carrying out activities of daily living, daily activities, appetite loss, aphasia, speech 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. Up to 10% of people following a stroke develop seizures, most commonly in the week subsequent to the event; the severity of the stroke increases the likelihood of a seizure. An estimated 15% of people experience urinary incontinence for more than a year following a stroke. 50% of people have a decline in sexual function (sexual dysfunction) following a stroke.

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 include anxiety, panic attacks, flat affect (failure to express emotions), mania, apathy and psychosis. Other difficulties may include a decreased ability to communicate emotions through facial expression, body language and voice. Disruption in self-identity, relationships with others, and emotional well-being can lead to social consequences after stroke due to the lack of ability to communicate. Many people who experience communication impairments after a stroke find it more difficult to cope with the social issues rather than physical impairments. Broader aspects of care must address the emotional impact speech impairment has on those who experience difficulties with speech after a stroke. Those who experience a stroke are at risk of paralysis which could result in a self disturbed body image which may also lead to other social issues. 30 to 50% of stroke survivors develop post-stroke depression, which is characterized by lethargy, irritability, Sleep disorder, sleep disturbances, lowered self-esteem and withdrawal. Clinical depression, Depression can reduce motivation and worsen outcome, but can be treated with social and family support, psychotherapy and, in severe cases, antidepressants. Psychotherapy sessions may have a small effect on improving mood and preventing depression after a stroke, however psychotherapy does not appear to be effective at treating depression after a stroke. Antidepressant medications may be useful for treating depression after a stroke. Emotional lability, another consequence of stroke, causes the person 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 person's actual emotions, a more severe form of emotional lability causes the affected person to laugh and cry pathologically, without regard to context or emotion. Some people show the opposite of what they feel, for example crying when they are happy. Emotional lability occurs in about 20% of those who have had a stroke. Those with a right hemisphere stroke are more likely to have an empathy problems which can make communication harder. Cognitive deficits resulting from stroke include perceptual disorders,

, dementia, and problems with attention and memory. A stroke survivor may be unaware of their own disabilities, a condition called anosognosia. In a condition called hemispatial neglect, the affected person is unable to attend to anything on the side of space opposite to the damaged hemisphere. Cognitive and psychological outcome after a stroke can be affected by the age at which the stroke happened, pre-stroke baseline intellectual functioning, psychiatric history and whether there is pre-existing brain pathology.

Epidemiology

Stroke world map-Deaths per million persons-WHO2012

Cerebrovascular disease world map - DALY - WHO2004

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 the southeastern United States, but causes of these disparities have not been explained. The risk of stroke Exponential growth, increases exponentially from 30 years of age, and the cause varies by age. Advanced age is one of the most significant stroke risk factors. 95% of strokes occur in people age 45 and older, and two-thirds of strokes occur in those over the age of 65. 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 childhood. 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. 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. Men are 25% more likely to develop strokes than women, yet 60% of deaths from stroke occur in women. Since women live longer, they are older on average when they have their strokes and thus more often killed. Some risk factors for stroke apply only to women. Primary among these are pregnancy, childbirth, menopause, and the treatment thereof (Hormone replacement therapy (menopause), HRT).

History

Episodes of stroke and familial stroke have been reported from the 2nd millennium BC onward in ancient Mesopotamia and Persia. Hippocrates (460 to 370 BC) was first to describe the phenomenon of sudden paralysis that is often associated with ischemia. Apoplexy, from the Greek language, Greek word meaning "struck down with violence", first appeared in Hippocratic writings to describe this phenomenon. The word ''stroke'' was used as a synonym for apoplectic seizure as early as 1599, and is a fairly literal translation of the Greek term. The term ''apoplectic stroke'' is an archaic, nonspecific term, for a cerebrovascular accident accompanied by haemorrhage or haemorrhagic stroke. Martin Luther was described as having an ''apoplectic stroke'' that deprived him of his speech shortly before his death in 1546. 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. Wepfer also identified the main arteries supplying the brain, the vertebral and carotid arteries, and identified the cause of a type of ischemic stroke known as a cerebral infarction when he suggested that apoplexy might be caused by a blockage to those vessels. Rudolf Virchow first described the mechanism of thromboembolism as a major factor. The term ''cerebrovascular accident'' was introduced in 1927, reflecting a "growing awareness and acceptance of vascular theories and (...) recognition of the consequences of a sudden disruption in the vascular supply of the brain". Its use is now discouraged by a number of neurology textbooks, reasoning that the connotation of fortuitousness carried by the word ''accident'' insufficiently highlights the modifiability of the underlying risk factors. ''Cerebrovascular insult'' may be used interchangeably. The term ''brain attack'' was introduced for use to underline the acute nature of stroke according to the

, which has used the term since 1990, and is used colloquially to refer to both ischemic as well as hemorrhagic stroke.

Research

As of 2017, angioplasty and stents were under preliminary clinical research to determine the possible therapeutic advantages of these procedures in comparison to therapy with

s, antithrombotics, or antihypertensive drugs.

References

External links

*
DRAGON Score for Post-Thrombolysis

THRIVE score for stroke outcome

National Institute of Neurological Disorders and Stroke
{{Authority control Stroke, Causes of death Wikipedia medicine articles ready to translate Wikipedia emergency medicine articles ready to translate

Classification

Definition

Ischemic

Hemorrhagic

Signs and symptoms

Early recognition

Subtypes

Associated symptoms

Causes

Thrombotic stroke

Embolic stroke

Cerebral hypoperfusion

Venous thrombosis

Intracerebral hemorrhage

Other

Silent stroke

Pathophysiology

Ischemic

Hemorrhagic

Diagnosis

Physical examination

Imaging

Underlying cause

Misdiagnosis

Prevention

Risk factors

Blood pressure

Blood lipids

Diabetes mellitus

Anticoagulation drugs

Surgery

Diet

Women

Previous stroke or TIA

Management

Ischemic stroke

Thrombolysis

Endovascular treatment

Craniectomy

Hemorrhagic stroke

Stroke unit

Rehabilitation

Spatial neglect

Automobile driving

Yoga

Action observation for upper limbs

Cognitive rehabilitation for attention deficits

Motor imagery for gait rehabilitation

Physical and occupational therapy

= Interventions for age-related visual problems in patients with stroke

Speech and language therapy

Orthotics#Ankle–foot orthosis (AFO), Devices

Physical fitness

Other therapy methods

Orthotics

Self-management

Prognosis

Physical effects

Emotional and mental effects

Epidemiology

History

Research

See also

References

Further reading

External links