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 ), 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.
The following are modifiable risk factors that contribute to increased risk of stroke:
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 myocardial infarction 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/or 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 )
Carotid artery stenosis
Hypercoagulability (thrombotic stroke only)
Use of certain drugs (eg, cocaine, amphetamines)
Anticoagulants and antiplatelet medications
Unmodifiable risk factors include the following:
Family history of stroke
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, 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
Neurologic deficits are used to determine the location of stroke (see table 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,
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 may result.
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 Ischemic Stroke 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 or hemorrhagic 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
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 impairment of consciousness
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 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.
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 is done to check for causes other than stroke(eg, postictal state, metabolic encephalopathies):
Blood tests: Comprehensive metabolic panel (including at least serum electrolytes, blood urea nitrogen [BUN], creatinine, and calcium levels), complete blood count (CBC) with differential and platelets, liver tests, and ammonia level
Arterial blood gases (ABGs)
Blood and urine culture and routine toxicology
Electrocardiography Electrocardiography The standard electrocardiogram (ECG) provides 12 different vector views of the heart’s electrical activity as reflected by electrical potential differences between positive and negative electrodes... read more (ECG) to check for myocardial infarction and new arrhythmias
Chest x-ray to check for new lung disease that may affect brain oxygenation.
Imaging tests to check for masses, hemorrhage, edema, evidence of bone trauma, and hydrocephalus (first, noncontrast head CT, followed by MRI or contrast CT if needed for diagnosis)
Echocardiography Echocardiography This photo shows a patient having echocardiography. This image shows all 4 cardiac chambers and the tricuspid and mitral valves. Echocardiography uses ultrasound waves to produce an image of... read more to check the heart for blood clots, pumping or structural abnormalities, and valve disorders
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
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.
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 ); 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, 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.
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 Speech Therapy Speech therapists can identify the most effective methods of communication for patients who have aphasia, dysarthria, or verbal apraxia or who have had a laryngectomy: Expressive aphasia: A... read more , 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 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 , strategies may include procedures (eg, carotid endarterectomy, stent placement), antiplatelet therapy, and anticoagulation.
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.
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