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1. A sudden loss of neurological function, caused by vascular injury (loss of blood flow) to an area of the brain. Because of the long-term disability it often produces, stroke is the disease most feared by older Americans.
SYN: SEE: apoplexy; SEE: brain attack; SEE: cerebrovascular accident SEE: carotid endarterectomy; SEE: intracranial hemorrhage; SEE: transient ischemic attack; SEE TABLE: Stroke and Its Causes
Stroke is both common and deadly: about 700,000 strokes occur in the U.S. each year. Stroke is the third leading cause of death in the U.S.
In the U.S., 80% of strokes are caused by cerebral infarct; intracranial hemorrhage and cerebral emboli are responsible for most other strokes.
Risk factors for stroke include advanced age (esp. older than 65 years), atherosclerosis of the aortic arch, atrial fibrillation, carotid artery disease, cigarette use, excessive alcohol use (more than five drinks daily), heart failure, hyperlipidemia, hypertension, a history of myocardial infarction, diabetes mellitus, male gender, close relation of someone who has had a stroke, nonwhite race, peripheral vascular disease, physical inactivity, obesity, using combination hormonal contraception (the pill, ring, patch), being pregnant or immediately postpartum, or a recent transient ischemic attack (TIA [informally a “ministroke” or a “warning stroke”]).
SYMPTOMS AND SIGNS
The National Institute of Neurological Disorders and Stroke lists the following as warning signs of stroke: sudden weakness or numbness of the face, arm, or leg; sudden loss of vision, double vision, dimming of vision in one or both eyes; sudden difficulty in speaking or in understanding speech; sudden severe headache; and sudden falling, gait disturbance, or dizziness. The patient who experiences these problems should call 911 immediately. If symptoms disappear in a few minutes, the individual may have experienced a TIA and should notify his or her primary care provider immediately for preventive care. In clinical practice, stroke patients often present with more than one stroke symptom, e.g., limb paralysis and aphasia; severe headache and hemibody deficits. It is also important to note that these symptoms are not specific for stroke: sudden dizziness or gait disturbance can occur as a result of intoxication with drugs or alcohol, for example, and sudden severe head pain can result from cluster headache, migraine, and many other disorders.
Diagnosis of stroke may be made by physical examination, e.g., taking a medical history of the symptoms and a neurological status helps in evaluating the location and severity of a stroke.
Diagnosis may also be made by neurological examination, e.g., the National Institutes of Health Stroke Scale (NIH-SS), computed tomography (CT) scans (usually without contrast enhancements), magnetic resonance imaging (MRI) scans, Doppler ultrasound, and arteriography.
Innovations in the management of stroke (in prevention, the early use of thrombolytic drugs, vascular ultrasonography, and endarterectomy) have revolutionized the acute and follow-up care of the stroke patient. Acute ischemic stroke can be treated with recombinant tissue plasminogen activator (rt-PA) if the disease is recognized in the first 90 to 270 min (4.5 hr) and intracerebral hemorrhage has been excluded with urgent CT or MRI scanning of the brain. This form of therapy is not without risk; thrombolytic drugs can reduce the potential for long-term disability and death by 20%, but increase the risk of hemorrhage. Hemorrhagic strokes, which have about a 50% mortality, can sometimes be treated by evacuating blood clots from the brain or by repairing intracerebral aneurysms.
Patients with hemorrhagic stroke should never receive fibrinolytic drugs. Other contraindications to fibrinolysis in stroke include recent or active bleeding or a known propensity for abnormal bleeding; recent lumbar puncture; recent arterial puncture; recent myocardial infarction; recent surgery or major trauma; seizure at the onset of the stroke; or blood pressure over 185/110 mm Hg that does not improve with simple therapies.
Acute phase: The patient suspected of stroke should be rapidly transported to the nearest certified comprehensive stroke center, if one is available. Hospitals without emergency stroke expertise should be bypassed. A rapid basic and neurological examination that uses a stroke rating scale (such as the NIH-SS) should be performed to triage patients for emergent mechanical thrombectomy or the administration of thrombolytics. Vitals signs should be assessed. Cardiac monitoring should be initiated and maintained for at least 24 hr. An assessment of blood glucose and either a noncontrast CT or MRI are needed before giving rt-PA. Low blood glucose may mimic stroke. Correction of hypoglycemia to normal range may make such so-called pseudostroke symptoms resolve. Evidence of brain hemorrhage or of a large hypodensity (an area on an x-ray film or image that is less dense than the surrounding area or less dense than normal) involving more than one third of the middle cerebral artery are contraindications to fibrinolytic therapy. Other tests such as serum chemistries, electrocardiogram (ECG), international normalized ratio (INR), and a complete blood count (CBC) should be performed, but do not need to precede administration of rt-PA. Blood pressure (BP) should be lowered to less than 185 systolic and 110 diastolic before giving thrombolysis. If thrombolysis is not given, the BP should be lowered only if it is above 220 systolic or 120 diastolic. IV rt-PA (dose 0.9 mg/kg, to a maximum dose of 90 mg) may be given safely to all patients within 3 hr of presentation and to selected patients between 3 and 4.5 hr (under the age of 80, not treated with anticoagulant drugs, no preceding stroke or diabetes, NIH-SS 25 or less, and appropriate CT findings). Aspirin is beneficial within 24 to 48 hr of onset of stroke. Other anticoagulants or antiplatelet drugs have not been proven to be effective. Neurological status is monitored for signs of deterioration or improvement, and findings are documented on a flow sheet. The National Institute of Neurological Disorders and Stroke suggests the following order of assessment in patients with suspected stroke: level of consciousness, eye movements, visual fields, facial movements, motor function of arms and legs, limb coordination, sensory responses, and language use, including clarity of speech. The patient is prepared for prescribed diagnostic studies, including MRI and/or CT, and, possibly, arteriography.
When rt-PA administration is complete, the patient is transferred to the neurological ICU or neurology unit. If clot-busting drugs cannot or should not be administered, monitoring and supportive care are provided. The ability to speak is assessed, and, if aphasia is present, a consultation by a speech therapist is obtained. A swallowing assessment is indicated. If patients cannot safely eat, a nasogastric tube should be placed. If patients cannot protect their airway, tracheal intubation and mechanical ventilation are needed. Bladder function is assessed; noninvasive measures are used to encourage voiding in the presence of urinary retention, voiding pattern is determined, and the incontinent patient is kept clean and dry. Use of indwelling catheters is limited because these promote urinary tract infection. Bowel function is assessed, and dietary intervention and stool softeners or laxatives as necessary are used to prevent constipation. Straining at stool or use of enemas is avoided. Fluid and electrolyte balance (intake, output, daily weight, laboratory values) is monitored and maintained. Adequate enteral or parenteral nutrition is provided as appropriate. Nursing measures are instituted to prevent complications of immobility. In consultation with occupational therapists and physical therapists, a program of positioning and mobility is initiated, as appropriate. Examples of activities include repositioning at least every 2 hr, maintaining correct body alignment, supporting joints to prevent flexion and rotation contractures, and providing range-of-motion exercises (passive to involved joints, active-assisted or active to uninvolved joints). Irrigation and lubrication prevent oral mucous membranes and eyes (cornea) from drying. Prescribed medical therapy is administered to decrease cerebral edema, and antihypertensives or anticoagulants are given as appropriate for etiology. The patient is observed for seizure activity, and drug therapy and safety precautions are initiated. Most stroke patients are hospitalized for a few days. Patient education about risk modification begins prior to discharge.
Rehabilitative phase: After the acute phase of stroke, rehabilitation goals depend on the severity of the patient's deficit, the age of the patient, the presence of comorbidities and prior functional status, his or her ability to perform activities of daily living independently, and the family and social support systems available. The rehabilitation program consists of various exercises, including neuromuscular retraining, motor learning and motor control, and functional activities that emphasize relearning or retraining in basic skills required for self-care. This may include instruction in the use of adaptive and supportive devices to facilitate independence in daily tasks. The goal of rehabilitation is to achieve an optimal functional outcome that will allow the patient to be discharged to the least restrictive environment. Ideally, the patient will achieve sufficient independence to return to community living, either independently or with family and community support.
All patient efforts should receive positive reinforcement. Patient communication is a priority. Exercises, proper positioning, and supportive devices help to prevent deformities. Quiet rest periods are provided based on the patient's response to activity. The patient should either assist with or perform own personal hygiene and establish independence in other activities of daily living. The rehabilitation team evaluates the patient's ability to feed self and continues to provide enteral feeding as necessary. A bowel and bladder retraining program is initiated, and both patient and family receive instruction in its management. Both patient and family are taught about the therapeutic regimen (activity and rest, diet, and medications), including desired effects and adverse reactions to report. Emotional lability, a consequence of some strokes, is recognized and explained, and assistance is provided to help the patient deal with changes in affect.
Poststroke care should not routinely include percutaneous gastrostomy tube feeding, hyperbaric oxygen therapy, nutritional supplements, corticosteroids, aggressive normalization of blood pressure in the acute phase, or antibiotic therapy.
IMPACT ON HEALTH
The best results are achieved by patients treated in specialized treatment centers with demonstrably low complication rates. All stroke patients are advised to reduce their risk for future stroke by taking prescribed antihypertensive drugs as directed; losing excess weight; exercising regularly; eating a well-balanced diet low in fat, cholesterol, sugar, and salt; stopping smoking; limiting alcohol intake; and maintaining glycemic control. Patient and family are referred to the American Stroke Association or local stroke groups for information and support (http://www.strokeassociation.org).
2. To rub gently in one direction, as in massage.
3. A gentle movement of the hand across a surface.
4. In dentistry, a complete simple movement that is often repeated with modifications of position, strength, or speed, perhaps as a part of a continuing activity; e.g., the closing stroke in mastication when the jaw closes and the teeth come together. In scaling or planing the roots of teeth, the scaling instrument is introduced carefully into the subgingival area in what is called an exploratory stroke, perhaps followed by a power stroke designed to break or dislodge encrusted calculus. This is followed by a shaving stroke, intended to smooth or plane the root surface.
5. A sharp blow.
Stroke and Its Causes
|Cause of Stroke||Frequency of Occurrence|
|Emboli from other organs, e.g., heart||about 15%|
|Cerebrovascular disease||greater than 50%|
|Trauma||less than 5%|
|Hypercoagulable states||less than 5%|
HEMORRHAGIC STROKE Bleeding into the brain, seen on noncontrast head CT (Courtesy of Harvey Hatch, MD, Curry General Hospital)
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