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Stroke Assesment and Treatments
Jay S. Luxenberg, MD and Ernest H. Rosenbaum, MD
There is a National Institutes of Health Stroke Scale that is often used for assessment. An irregular pulse may suggest atrial fibrillation or elevated blood pressure, or a hypertensive encephalopathy (brain dysfunction), and this precludes thrombolysis if blood pressures are over 185/110. A carotid bruit suggests carotid artery narrowing or stenosis.
Laboratory tests: Blood glucose for hypoglycemia, CBC, prothrombin time, and a partial thromboplastin time (PTT), especially if thrombolytic therapy is being considered, and an EKG to rule out atrial fibrillation or an acute myocardial infarction. Strokes may be complicated by myocardial ischemia or arrhythmias or a heart attack, and monitoring for these for twenty-four hours is recommended. Perform an echocardiogram if infective endocarditis is suspected.
Imaging: A cerebral infarction cannot be distinguished from a hemorrhage based on symptoms, and either a CAT scan or MRI is required to differentiate these two entities. Non-contrast CTs are more available and less expensive and can be sensitive for diagnosis of acute hemorrhage, but MRI has a higher sensitivity for acute ischemic changes.
When intra-arterial thrombolysis or mechanical clot retrieval is considered, CT or MRI angiography is useful to identify the site of arterial occlusion. They provide complete visualization from the aortic arch to the Circle of Willis and beyond.
Intravenous thrombolysis: The National Institute of Neurological Disorders and Stroke Recombinant Tissue Plasminogen Activator (NINDSrt-PA) Stroke Study demonstrated the efficacy of intravenous rt-PA within three hours of the onset of stroke symptoms. Maximal total dose is 90 mg. Thirty one to fifty percent had a favorable neurological or functional outcome at three months versus 20-38% in those who received a placebo. The mortality rates were similar in both groups. Symptomatic intracranial hemorrhage occurred in 6%. More studies that treated with rt-PA six hours after onset of symptoms failed to find benefit from thrombolysis versus treatment at three hours, but benefits are greatest when started as early as possible. The incidence of intracranial hemorrhage increases with age.
Aspirin. Two large studies have shown that between 160 to 300 mg per day initiated within 48 hours after the onset of the stroke and continued for two weeks or until discharge reduced the death rate and dependency at discharge or at six months. This was probably due to reducing the risk of recurrent ischemic strokes. The benefits were small, as one needed to treat 77 patients to obtain one patient with an improved outcome. The safety profile was good. Aspirin should be withheld during the first twenty-four hours.5
- The Role of Anticoagulant Therapy
- Six meta-analysis studies involving 21,966 patients found no evidence of the value of anticoagulants, either heparin, low molecular weight, thrombin inhibitors, or oral anticoagulants in the acute phase, improved functional outcome. Also, there was no proven functional improvement using anticoagulants with acute cardioembolic strokes, as well.
- Prevention of complications:
- 1. Nutrition is a major problem; although, routine use of oral nutritional supplements or tube feedings to prevent or treat under nutrition in hospitalized stroke patients resulted in long-term functional outcome.
2. Prevention of deep venous thrombosis and pulmonary emboli, which are increased risks, especially with age and stroke severity (often with leg paralysis). A lot is dependent on stroke severity. Anticoagulants did not improve overall functional outcomes; although, unfractionated heparin or a low-molecular weight heparin has been recommended in patients at high risk for deep vein thrombosis, especially for immobile patients.
3. Patients with large supratentorial infarcts, which are space occupying with brain edema, are at higher risk for uncal herniation between the second and fifth days with high case mortality up to 78%. There is no proven effective medical treatment thus far.
4. Surgical treatment for space occupying lesions in the region of the middle cerebral artery in the first 48 hours after stroke onset reduced fatal mortalities to 22% versus 78% in the medical management group and decreased disability to 57% from 79%.
5. It is important to control hypertension, hypercholesterolemia with statin therapy, as well as control diabetes, promote smoking cessation, and use of carotid endarterectomy for stenosis when indicated.
- Even in the United States, only a small percentage of patients receive rt-PA intravenous due to the restriction of the three-hour time window after onset of symptoms. There have been no conclusive studies proving intravenous thrombolysis recanalizes occluded arteries. There has been recanalization of an occluded middle cerebral artery two hours after thrombolysis in up to one-third of patients.
Newer technology is being developed. Improved function and less disability have been seen when the thrombolytic therapy was directed against the site of the occlusion. This could be a more rapid treatment and improved recanalization.
Other essential early treatments:
- 1. Control high blood pressure.
2. Control high glucose levels.
3. Reduce body temperature in the first few hours, as these factors lead to a higher mortality.
4. Check cholesterol. Treat if elevated (see a cardiologist).
- The Debate on Whether Lowering the Blood Pressure Affects Cerebral Profusion
- The current consensus recommends withholding anti-hypertensive therapy during the acute phase unless the diastolic blood pressure exceeds 120 mmHg of mercury or a systolic over 220mmHg of mercury. Patients with such blood pressures are not candidates for rt-PA thrombolysis therapy. Try to maintain systolic pressure under 188mmHg and diastolic at less than 105mmHg of mercury.
- Ways of Neuroprotection
- There are many strategies known, but only rt-PA and aspirin have been shown to be clearly effective.
- Hypothermia has been shown to reduce infarct volume and improve neurologic outcomes in animal models and improved functional outcomes in randomized clinical patient trials with global cerebral ischemia after cardiac arrest, but results were not consistent with traumatic brain injury.
- After a clinical evaluation, and if less than three hours, rt-PA should be considered after clearance with either a CAT scan or an MRI to rule out the chances of a hemorrhagic stroke. Aspirin should be started after twenty-four hours, 300 mg daily for the first two weeks and then a lower dose, and dypridamole is considered for secondary prevention. Aggressive management of cardiovascular diabetic hypertensive risk factors, smoking cessation, hypertension control and statins for lipid disorders are warranted.
- Contraindications to Thrombolysis
- Onset greater than three hours, intravenous hemorrhage by CT or MRI, head trauma or stroke in prior three months, myocardial infarction in less than three months, GI or other hemorrhage, major surgery two weeks earlier, history of intracranial hemorrhage, systolic blood pressure greater than 185 or diastolic greater than 110mmHg of mercury. Also, evidence of active bleeding, oral anticoagulation therapy with an INR greater than 1.7, prior use of heparin 48 hours with prolonged PTT, and a platelet count less than 100,000 per cubic mm, blood sugar less than 30 mg/dl.
- Acute Cardioembolic Stroke6
- Anticoagulants were shown to increase intracerebral bleeding and did not reduce death or disability in acute cardioembolic stroke. In a randomized control trial comparing anticoagulants (unfractionated heparin, low-molecular-weight heparin, or heparinoids) with other treatments or placebo given within 48 hours of the onset of a stroke were assessed. There were 4,624 patients in the series, of which 3797 had atrial fibrillation, and 827 had other cardioembolic sources.
The results of the study showed that anticoagulants did not differ significantly from placebo or aspirin for death or disability and recurrent strokes or all strokes, but they did increase the risk of symptomatic intracranial bleeding. Thus, there was no major difference between the anticoagulant placebo and aspirin for death or disability from stroke, but they did increase the risk for intracranial bleeding.
Of note is that short-term anticoagulation is commonly used for ischemic strokes - some ten years ago heparin was commonly used. Paciaroni and colleagues have shown that there were no benefits of anticoagulation when given within hours of an ischemic stroke, but did increase the risk for hemorrhagic complications. They felt that short-term anticoagulation for reducing the risk for recurrent ischemic stroke, and there was no net benefit in mortality or disability.
The prophylactic use of heparins for deep venous thrombosis still remains somewhat uncertain in non- ambulatory patients, and this is still being investigated. A lower dose for prophylaxis is more effective than compression devices, but those with cardioembolic transischemic attacks may also benefit in short-term anticoagulation, as the risk for recurrence is particularly high for patients, and the risk for brain hemorrhages should be substantially lower in the absence of major brain infarction.
- The Role of Exercise and Your Brain
- Doing aerobic exercise increases the blood flow to the brain, which can help brain cell nourishment and can improve brain function and cognition.
There are summary searches, showing the growth of new brain cell neurons in the hippocampus area of the brain, which controls learning and memory. Walking twenty to thirty minutes a day is a good exercise.
Researchers say specialized treadmill may help stroke patients re-learn how to walk. A "specialized treadmill can help stroke patients learn to walk correctly again,"7 ..."seven stroke patients who did what's called locomotor treadmill training with partial body-weight support, which uses a treadmill outfitted with a harness. By securing patients to a harness to support a portion of their body weight while they walk on the treadmill helped patients re-learn how to walk in a safe and controlled way. Early intervention is vital for success. Patients started on the treadmill as soon as possible during the acute period of recovery after their stroke."
Vigorous walking for about an hour a day five times a week can chop a dozen years off the biological age of persons 64 and older.8
Physical activity can extend a patient's functional independence, suggested Roy Shephard, MD, PhD., of the University of Toronto and colleagues.9
The researchers found that "a loss of at least four to five mL/kg/min" of oxygen "per decade continues into advanced old age," limiting "the amount of activity a patient could participate in without becoming fatigued."
In patients over 64, vigorous walking boosted "maximal oxygen intake by about 25 percent within three months." Moreover, those individuals had an "increase in maximal oxygen intake of six mL/kg/min, or a decrease of about 12 years of biological age."
Physical activity "also hastens recovery from injuries, and any additional muscle power may prevent falls."
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