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Overview of Stroke


Andrei V. Alexandrov

, MD, The University of Tennessee Health Science Center;

Balaji Krishnaiah

, MD, The University of Tennessee Health Science Center

Reviewed/Revised Jul 2023
Topic Resources

Strokes are a heterogeneous group of disorders involving sudden, focal interruption of cerebral blood flow that causes neurologic deficit. Strokes can be

In the US, stroke is the 5th most common cause of death and the most common cause of neurologic disability in adults.

Strokes involve the arteries of the brain (see figure ), either the anterior circulation (branches of the internal carotid artery) or the posterior circulation (branches of the vertebral and basilar arteries).

Arteries of the Brain

The anterior cerebral artery supplies the medial portions of the frontal and parietal lobes and corpus callosum. The middle cerebral artery supplies large portions of the lateral surfaces of frontal, parietal, and temporal lobes. Branches of the anterior and middle cerebral arteries (lenticulostriate arteries) supply the basal ganglia and anterior limb of the internal capsule.

The vertebral and basilar arteries supply the brain stem, cerebellum, posterior cerebral cortex, and medial temporal lobe. The posterior cerebral arteries bifurcate from the basilar artery to supply the medial temporal (including the hippocampus) and occipital lobes, thalamus, and mammillary and geniculate bodies.

Anterior circulation and posterior circulation communicate in the circle of Willis via the posterior communicating artery.

Arteries of the Brain

Risk factors

The following are modifiable risk factors that contribute to increased risk of stroke:

Unmodifiable risk factors include the following:

  • Prior stroke

  • Older age

  • Family history of stroke

  • Race ethnicity

  • Genetic factors

Symptoms and Signs of Stroke

Initial symptoms of stroke occur suddenly. Symptoms depend on the location of infarction (see figure Areas of the brain by function Areas of the brain by function Areas of the brain by function ).

Thus, symptoms can include numbness, weakness of limbs or face; aphasia; confusion; visual disturbances in one or both eyes (eg, transient monocular blindness, diplopia Diplopia Diplopia is the perception of 2 images of a single object. Diplopia may be monocular or binocular. Monocular diplopia is present when only one eye is open. Binocular diplopia disappears when... read more ); dizziness or loss of balance and coordination; and headache.

Areas of the brain by function

Areas of the brain by function

Neurologic deficits are used to determine the location of stroke (see table Selected Stroke Syndromes Selected Stroke Syndromes Selected Stroke Syndromes ). Anterior circulation stroke typically causes unilateral symptoms. Posterior circulation stroke can cause unilateral or bilateral deficits and is more likely to affect consciousness, especially when the basilar artery is involved.


Systemic or autonomic disturbances (eg, hypertension, fever) occasionally occur.

Other manifestations, rather than neurologic deficits, often suggest the type of stroke. For example,


Stroke complications can include sleep problems, confusion, depression, incontinence, atelectasis, pneumonia, and swallowing dysfunction, which can lead to aspiration, dehydration, or undernutrition. Immobility can lead to thromboembolic disease, deconditioning, sarcopenia, urinary tract infections, pressure ulcers, and contractures.

Daily functioning (including the ability to walk, see, feel, remember, think, and speak) may be decreased.

Evaluation of Stroke

Evaluation aims to establish the following:

Stroke is suspected in patients with any of the following:

When stroke is suspected, clinicians may use standardized criteria to grade severity and follow changes over time. This approach can be particularly useful as an outcome measure in efficacy studies. The National Institutes of Health Stroke Scale (NIHSS) is often used. It is a 15-item scale to evaluate the patient's level of consciousness and language function and to identify motor and sensory deficits by asking the patient to answer questions and to perform physical and mental tasks. It is also useful for choosing appropriate treatment and predicting outcome.


Glucose is measured at bedside to rule out hypoglycemia. Measurement of blood glucose is the only laboratory test needed for all patients before thrombolytics are given. However, if the patient is receiving an anticoagulant, platelet count, international normalized ratio (INR), and partial thromboplastin time are measured.

If stroke is still suspected, immediate neuroimaging Diagnosis Ischemic stroke is sudden neurologic deficits that result from focal cerebral ischemia associated with permanent brain infarction (eg, positive results on diffusion-weighted MRI). Common causes... read more Diagnosis is required to differentiate hemorrhagic from ischemic stroke and to detect signs of increased intracranial pressure. CT is sensitive for intracranial blood but may be normal or show only subtle changes during the first hours of symptoms after anterior circulation ischemic stroke. CT also misses some small posterior circulation strokes. MRI is sensitive for intracranial blood and may detect signs of ischemic stroke missed by CT, but CT can usually be done more rapidly. If CT does not confirm clinically suspected stroke, diffusion-weighted MRI can usually detect ischemic stroke.

Images of Ischemic Stroke

If consciousness is impaired and lateralizing signs are absent or equivocal, further testing Testing Coma is unresponsiveness from which the patient cannot be aroused and in which the patient's eyes remain closed. Impaired consciousness refers to similar, less severe disturbances of consciousness... read more Testing is done to check for causes other than stroke(eg, postictal state, metabolic encephalopathies):

After the stroke is identified as ischemic or hemorrhagic, tests are done to determine the cause. Patients are also evaluated for coexisting acute general disorders (eg, infection, dehydration, hypoxia, hyperglycemia, hypertension). Patients are asked about depression, which commonly occurs after stroke. A dysphagia team evaluates swallowing; sometimes a barium swallow study is necessary.

Treatment of Stroke

  • Stabilization

  • Reperfusion for some ischemic strokes

  • Supportive measures and treatment of complications

  • Strategies to prevent future strokes

  • Rehabilitation

Specific acute treatments vary by type of stroke. They may include reperfusion Acute stroke treatment Acute stroke treatment (eg, IV thrombolysis, mechanical thrombectomy) for some ischemic strokes.

Providing supportive care, correcting coexisting abnormalities (eg, fever, hypoxia, dehydration, hyperglycemia, sometimes hypertension), and preventing and treating complications are vital during the acute phase and convalescence (see table Strategies to Prevent and Treat Stroke Complications Strategies to Prevent and Treat Stroke Complications Strategies to Prevent and Treat Stroke Complications ); these measures clearly improve clinical outcomes (1 Treatment reference Strokes are a heterogeneous group of disorders involving sudden, focal interruption of cerebral blood flow that causes neurologic deficit. Strokes can be Ischemic (80%), typically resulting... read more Treatment reference ). During convalescence, measures to prevent aspiration Prevention Aspiration pneumonitis and pneumonia are caused by inhaling toxic and/or irritant substances, most commonly large volumes of upper airway secretions or gastric contents, into the lungs. Chemical... read more , deep venous thrombosis Deep Venous Thrombosis (DVT) Prevention It is preferable and safer to prevent deep venous thrombosis (DVT) than to treat it, particularly in high-risk patients. DVT prophylaxis begins with risk assessment. Risk, along with other factors... read more , urinary tract infections Prevention Bacterial urinary tract infections (UTIs) can involve the urethra, prostate, bladder, or kidneys. Symptoms may be absent or include urinary frequency, urgency, dysuria, lower abdominal pain... read more , pressure ulcers Pressure Injuries A hospital may provide emergency medical care, diagnostic testing, intensive treatment, or surgery, which may or may not require admission. Older patients use hospitals more than younger patients... read more , and undernutrition Undernutrition A hospital may provide emergency medical care, diagnostic testing, intensive treatment, or surgery, which may or may not require admission. Older patients use hospitals more than younger patients... read more may be necessary. Passive exercises, particularly of paralyzed limbs, and breathing exercises are started early to prevent contractures, atelectasis, and pneumonia.


Depression after stroke may require antidepressants; many patients benefit from counseling.

Modifying risk factors through lifestyle changes (eg, stopping cigarette smoking) and medications (eg, for hypertension) can help delay or prevent subsequent strokes. Other stroke prevention strategies are chosen based on the patient's risk factors. For ischemic stroke prevention Long-term stroke treatment Long-term stroke treatment , strategies may include procedures (eg, carotid endarterectomy, stent placement), antiplatelet therapy, and anticoagulation.

Treatment reference

  • 1. Powers WJ, Rabinstein AA, Ackerson T, et al:Guidelines for the early management of patients with acute ischemic stroke: 2019 update to the 2018 guidelines for the early management of acute ischemic stroke: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 50 (12):3331–3332, 2019. doi: 10.1161/STROKEAHA.119.027708 Epub 2019 Oct 30.

Prognosis for Stroke

The sooner a stroke is treated, the less severe brain damage is likely to be and the better the chances for recovery.

Certain factors suggest a poor outcome. Strokes that impair consciousness or that affect a large part of the left side of the brain may be particularly grave.

Usually, the more quickly patients improve during the days after stroke, the more they will ultimately improve. Improvement commonly continues for 6 to 12 months after the stroke. In adults who have had an ischemic stroke, problems that remain after 12 months are likely to be permanent, but children continue to improve slowly for many months. Older people fare less well than younger people. For people who already have other serious disorders (eg, dementia), recovery is more limited. Of all the different causes of strokes, lacunar strokes have the best prognosis.

If a hemorrhagic stroke is not massive and intracranial hypertension is absent the outcome is likely to be better than that after an ischemic stroke with similar symptoms. Blood (in a hemorrhagic stroke) does not damage brain tissue as much as ischemia does.

Drugs Mentioned In This Article

Drug Name Select Trade
Aluvea , BP-50% Urea , BP-K50, Carmol, CEM-Urea, Cerovel, DermacinRx Urea, Epimide-50, Gord Urea, Gordons Urea, Hydro 35 , Hydro 40, Kerafoam, Kerafoam 42, Keralac, Keralac Nailstik, Keratol, Keratol Plus, Kerol, Kerol AD, Kerol ZX, Latrix, Mectalyte, Nutraplus, RE Urea 40, RE Urea 50 , Rea Lo, Remeven, RE-U40, RYNODERM , U40, U-Kera, Ultra Mide 25, Ultralytic-2, Umecta, Umecta Nail Film, URALISS, Uramaxin , Uramaxin GT, Urea, Ureacin-10, Ureacin-20, Urealac , Ureaphil, Uredeb, URE-K , Uremez-40, Ure-Na, Uresol, Utopic, Vanamide, Xurea, X-VIATE
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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