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Stroke is a permanent, localized loss of brain or retinal
function due to decreased blood supply and oxygen or bleeding within the brain. It is a
major cause of death and disability in the United States.
Types
A. Ischemic. Eighty percent of all strokes are ischemic (i.e. due to a decreased blood
supply) in origin.
B. Hemorrhagic. Seventy percent of hemorrhagic (bleeding) events occur within brain tissue
(intracerebral hemorrhage).
Causes
A. Ischemic.
The majority of ischemic stroke events are due to underlying atherosclerosis (artery
disease). Nonatherosclerotic causes should be considered in children, adults less than 45
years old, and individuals without risk factors for atherosclerosis. A type of arrhythmia
(rhythm disturbance) in the heart referred to as atrial fibrillation (AF) is an important
cause of stroke.
B. Hemorrhagic.
Intracerebral hemorrhage (bleeding within the brain) is most often secondary to underlying
high blood pressure; other important causes include a bleeding disorder, local widening of
an artery in the brain, tumor, or other causes.
Symptoms
Presenting symptoms are useful for determining the location, cause, and type of stroke.
The clinical presentation of stroke depends on the vascular distribution affected. The
majority of ischemic strokes occur in the carotid system. Hemorrhage can involve cerebral
tissue of more than one vascular distribution. Symptoms include sudden blindness,
difficulties understanding or speaking, loss of feeling, and decreased stength, or
paralisis.
Diagnosis
A. History: Embolic infarctions (stroke due to a clot which occurs somewhere else and then
moves to the brain) characteristically develop suddenly, as do hemorrhagic events.
Thrombotic strokes (strokes due to a clot in the artery which causes the artery to close)
may have a slow or stuttering onset and often develop during sleep. Severe headache,
vomiting, mental status change, and nuchal rigidity are more common with hemorrhagic
events but are not always present. The presence of atherosclerotic or cardioembolic
disease or risk factors can also be helpful in determining the cause of a stroke.
B. A thorough physical examination should be performed, with particular attention to
muscle strength and the neurologic system.
C. Laboratory assessment
1. Imaging studies. CT and MRI are helpful.
2. ECG and chest radiography. Stroke can occur coincident with myocardial infarction
(heart attack). Patients at risk for AF should have cardiac monitoring. A chest radiograph
is helpful.
3. Blood tests. A complete blood test is useful.
4. Lumbar puncture. Analysis of the spinal fluid may be useful in certain circumstances.
5. Other. A lateral cervical spine film is necessary for patients with coma of unknown
cause and those with neck pain or cervical spine tenderness. An EEG is useful if seizure
is suspected. Duplex carotid imaging can determine the severity and location of carotid
atherosclerosis but may not accurately differentiate between vessel occlusion and very
high grade stenosis. Transthoracic echocardiography is useful in the presence of clinical
evidence of heart disease or a high suspicion of cardioembolism.
Treatment
A. Ischemic
1. General. Supportive treatment.
a. Blood pressure should be controlled.
b. Swallowing and bladder and bowel function should be evaluated and any disorder treated.
c. Mobilization. Daily passive range-of-motion joint exercises should begin promptly,
followed by more active exercises.
2. Pharmacologic. There is presently no treatment that reverses or lessens the amount of
acute ischemic damage after stroke. Heparin (to maintain the partial thromboplastin time
between 1.5 and 2.5 times baseline) has only been proven useful in the treatment of acute
cardioembolic stroke. Uncontrolled hypertension or a large infarct are contraindications
to early anticoagulation. No direct data support the use of aspirin, ticlopidine, or
warfarin (Coumadin) acutely, although extrapolated secondary prevention data suggest that
there may be a role for aspirin.
3. Rehabilitation This has two phases, acute and recuperative. See your physician for
details.
B. Hemorrhagic stroke
1. General. Careful lowering of blood pressure to prehemorrhage levels is necessary.
2. Pharmacologic. Seizure prophylaxis is commonly used for certain hemorrhagic stroke
patients. Patients with cerebral edema (fluid accumulation in the brain) are treated with
steroids.
3. Surgical. The decision to evacuate a hematoma (bleeding in the brain) surgically
is individualized.
4. Rehabilitation This has two phases, acute and recuperative. See your physician for
details.
Prevention and Risk Factors
Risk factors for stroke include older age, male sex, hypertension, cigarette use,
hyperlipidemia, diabetes mellitus, heavy alcohol use, obesity, inactive lifestyle, AF,
atherosclerosis, black race, and oral contraceptive use.
1. Lifestyle modification. Treatment of hypertension and cessation of cigarette use reduce
stroke risk. Moderating alcohol use, lowering blood lipids, exercising, and strict control
of glucose in diabetic patients are unproven methods of reducing stroke risk but are
recommended for their general health benefits.
2. Pharmacologic. Aspirin and warfarin are effective in certain patients to help the
prevention of strokes.
3. Surgical. Data suggest that asymptomatic but highly select patients with carotid
diameter stenosis greater than 60% have a reduced 5-year stroke rate with carotid
endarterectomy when treated in centers with perioperative morbidity and mortality of less
than 3%.
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