Strokes are a heterogeneous group of disorders involving sudden, focal interruption of cerebral blood flow that causes neurologic deficit. Strokes can be
Hemorrhagic (20%), resulting from vascular rupture (eg, subarachnoid hemorrhage Subarachnoid Hemorrhage (SAH) Subarachnoid hemorrhage is sudden bleeding into the subarachnoid space. The most common cause of spontaneous bleeding is a ruptured aneurysm. Symptoms include sudden, severe headache, usually... read more
, intracerebral hemorrhage Intracerebral Hemorrhage Intracerebral hemorrhage is focal bleeding from a blood vessel in the brain parenchyma. The cause is usually hypertension. Typical symptoms include focal neurologic deficits, often with abrupt... read more 
)
Transient stroke symptoms (typically lasting < 1 hour) without evidence of acute cerebral infarction (based on diffusion-weighted MRI) are termed a transient ischemic attack Transient Ischemic Attack (TIA) A transient ischemic attack (TIA) is focal brain ischemia that causes sudden, transient neurologic deficits and is not accompanied by permanent brain infarction (eg, negative results on diffusion-weighted... read more (TIA).
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 
), 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.  |
Risk factors
The following are modifiable factors that contribute to increased risk of stroke:
Cigarette smoking
Abdominal obesity
Lack of physical activity
High-risk diet (eg, high in saturated fats, trans fats, and calories)
Heart disorders (particularly disorders that predispose to emboli, such as acute MI Acute Myocardial Infarction (MI) Acute myocardial infarction is myocardial necrosis resulting from acute obstruction of a coronary artery. Symptoms include chest discomfort with or without dyspnea, nausea, and diaphoresis.... read more
, infective endocarditis Infective Endocarditis Infective endocarditis is infection of the endocardium, usually with bacteria (commonly, streptococci or staphylococci) or fungi. It may cause fever, heart murmurs, petechiae, anemia, embolic... read more 
, and atrial fibrillation Atrial Fibrillation and Wolff-Parkinson-White Syndrome (WPW) In Wolff-Parkinson-White syndrome, antegrade conduction occurs over an accessory pathway. If atrial fibrillation, develops this is a medical emergency as very rapid ventricular rates can develop... read more )Hypercoagulability (thrombotic stroke only)
Use of certain drugs (eg, cocaine, amphetamines)
Unmodifiable risk factors include the following:
Prior stroke
Older age
Family history of stroke
Genetic factors
Risk factor reference
1. Kernan WN, Viscoli CM, Furie KL, et al: Pioglitazone after ischemic stroke or transient ischemic attack. N Engl J Med 374 (14):1321–1331, 2016. doi: 10.1056/NEJMoa1506930.
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 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 ).
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
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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 ). 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,
Sudden, severe headache suggests subarachnoid hemorrhage.
Impaired consciousness or coma, often accompanied by headache, nausea, and vomiting, suggests increased intracranial pressure Symptoms and Signs Intracranial tumors may involve the brain or other structures (eg, cranial nerves, meninges). The tumors usually develop during early or middle adulthood but may develop at any age; they are... read more
, which can occur 48 to 72 hours after large ischemic strokes and earlier in many hemorrhagic strokes; fatal brain herniation Pathophysiology 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 
may result.
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 
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.
This image shows low attenuation in the distribution of the right middle cerebral artery consistent with a subacute infarct.
© 2017 Elliot K. Fishman, MD.
This MRI scan shows an area of restricted diffusion consistent with an acute ischemic stroke in the left insular and frontal lobes.
Image courtesy of Ji Y. Chong, MD.
This noncontrast head CT scan shows a hyperdense left middle cerebral artery. This finding indicates a focal clot in the left middle cerebral artery (arrow).
Image courtesy of Ji Y. Chong, MD.
If consciousness is impaired and lateralizing signs are absent or equivocal, further tests 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 to check for other causes are done.
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
Stabilization may need to precede complete evaluation. Comatose or obtunded patients (eg, Glasgow Coma Score ≤ 8) may require airway support Overview of Mechanical Ventilation Mechanical ventilation can be Noninvasive, involving various types of face masks Invasive, involving endotracheal intubation Selection and use of appropriate techniques require an understanding... read more . If increased intracranial pressure is suspected, intracranial pressure monitoring Intracranial Pressure (ICP) Monitoring Some monitoring of critical care patients depends on direct observation and physical examination and is intermittent, with the frequency depending on the patient’s illness. Other monitoring... read more and measures to reduce cerebral edema Increased intracranial pressure Traumatic brain injury (TBI) is physical injury to brain tissue that temporarily or permanently impairs brain function. Diagnosis is suspected clinically and confirmed by imaging (primarily... read more 
may be necessary.
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 (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 ); 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 ). 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.
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 , 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.
