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Overview of Stroke

By

Ji Y. Chong

, MD, Weill Cornell Medical College

Last full review/revision Apr 2020
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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 Arteries of the brain Overview of Stroke 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 Overview of Stroke ), 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 frontal, parietal, and temporal lobe surfaces. 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.

Arteries of the brain

Risk factors

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

Unmodifiable risk factors include the following:

  • Prior stroke

  • Older age

  • Family history of stroke

  • Genetic factors

Risk factor reference

Symptoms and Signs of Stroke

Thus, symptoms can include numbness, weakness of limbs or face; aphasia; confusion; visual disturbances in one or both eyes (eg, transient monocular blindness); 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 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 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.

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

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

Complications

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:

  • Whether stroke has occurred

  • Whether stroke is ischemic or hemorrhagic

  • Whether emergency treatment is required

  • What the best strategies for preventing subsequent strokes are

  • Whether and how to pursue rehabilitation

Stroke is suspected in patients with any of the following:

  • Sudden neurologic deficits compatible with brain damage in an arterial territory

  • A particularly sudden, severe headache

  • Sudden, unexplained coma

  • Sudden impairment of consciousness

Glucose is measured at bedside to rule out hypoglycemia.

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

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

Specific acute treatments vary by type of stroke. They may include reperfusion Acute stroke treatment 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 Acute stroke treatment (eg, recombinant tissue plasminogen activator, 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 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 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, usually gastric contents, into the lungs. Chemical pneumonitis, bacterial pneumonia, or airway obstruction... 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.

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After a stroke, most patients require rehabilitation Stroke Rehabilitation Rehabilitation after stroke aims to preserve or improve range of motion, muscle strength, bowel and bladder function, and functional and cognitive abilities. Specific programs are based on the... read more (occupational and physical therapy) to maximize functional recovery. Some need additional therapies (eg, speech therapy, feeding restrictions). For rehabilitation, an interdisciplinary approach is best.

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

Modifying risk factors through lifestyle changes (eg, stopping cigarette smoking) and drug therapy (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 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 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: 2018 Guidelines for the early management of patients with acute ischemic stroke: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 49 (3):e46–e110, 2018. doi: 10.1161/STR.0000000000000158. Epub 2018 Jan 24.

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