Oilman Wyatt in the hospital after suffering stroke Houston Chronicle, United States - Nov 26, 2008 Wyatt also helped lead and finance a proxy battle to oust management and install a new board at El Paso in 2003 after its shares cratered throughout 2002 in ...
Once you warn Web addicts, follow through Anchorage Daily News, AK - The referral agency we partner with in this asked if we would consider an individual who had aphasia as the result of a stroke. She tells us this individual ...
Obama looks to FDR as pacesetter San Francisco Chronicle, USA - Nov 30, 2008 ... blocking the Bureau of Land Management from opening 360000 acres of sensitive public lands in Utah to oil and gas drilling. With the stroke of a pen, ...
Stroke: Practical Management Journal of American Medical Association (subscription), IL - Nov 18, 2008 The problem of slow implementation of geographically defined acute stroke units in all hospitals admitting patients with acute stroke is worrisome to all ...
Drugs you can't have Stuff.co.nz, New Zealand - Nov 30, 2008 Injections of synthetic insulin several times a day are needed to avoid acute problems such as hypoglycaemia and coma, and serious long-term problems such ...
Rub?n Rosario: In Lydia Lunney's eyes, everyone was royalty Pioneer Press, MN - Nov 29, 2008 Only a massive stroke Nov. 18 could stop Lunney from her nearly eight-decade-long work duties. It apparently took place in her St. Paul home, sometime after ...
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Recent News and Articles on the Keywords: acute stroke + stroke + acute Related to the article below (Last Update: 8/5/2008)
Telemedicine Improves Rural Stroke Care MedPage Today, NJ - Aug 4, 2008 4 -- Video consultation improves accuracy of diagnosis and treatment of acute stroke in remote areas, researchers found. Telemedicine consultation with a ...
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Patients With Suspected Stroke Should Be Admitted Directly To ... Medical News Today (press release), UK - Jul 29, 2008 The NICE guideline 'Diagnosis and initial management of acute stroke and transient ischaemic attack (TIA)' covers the acute stage of a stroke or TIA, ...
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[CITATION] … trial of streptokinase, aspirin, and combination of both in treatment of acute ischaemic stroke MAS Trial-Italy - Lancet, 1995
Introduction A stroke occurs when there is interruption of blood flow to the brain. As a result, there is inadequate delivery of oxygen and glucose to brain tissue, which results in death of brain cells (neurons). In order to prevent irreversible death of brain tissue, blood flow must be restored as quickly as possible. Persons must therefore be familiar with the signs and symptoms of a stroke so they can access and receive immediate medical attention. The symptoms of a stroke can vary, depending upon which part of the brain is affected. It is important to realize that a stroke is not painful and generally does not cause a headache (the one exception is subarachnoid hemorrhage, which is discussed below). Examples of common stroke symptoms include the following:
numbness on one side of the body (hemi-anesthesia) weakness on one side of the body (hemiparesis) difficulty with eyesight or vision
complete or partial loss of the visual field (vision to one side), which involves both eyes (hemianopia) complete or partial loss of vision in one eye (amaurosis fugax)
double vision (diplopia)
the sensation of spinning (vertigo) slurred speech (dysarthria)
disturbance of language functions (aphasia)
inability to express oneself, through both speech and writing (expressive aphasia, Broca's aphasia, non-fluent aphasia)
inability to comprehend what is being said or read (receptive aphasia, Wernicke's aphasia, fluent aphasia)
These symptoms can occur in isolation or in combination with each other. Recognition of these symptoms by the individual experiencing them or by family or friends should prompt an immediate 911 call for transport to the nearest emergency room.
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Management of Acute Stroke
Related Programs:
Secondary Prevention: Stopping the Next Stroke
Caregiver Involvement in Post-Stroke Care
TIA: A Warning Not to be Ignored
Treating Stroke: How to Reduce the Damage
By: Kyra Becker, MD
Introduction
Different Stroke Classes
Tissue Plasminogen Activator (tPA)
Post-Stroke Conditions
Conclusion
Introduction
A stroke occurs when there is interruption of blood flow to the brain. As a result, there is inadequate delivery of oxygen and glucose to brain tissue, which results in death of brain cells (neurons).
In order to prevent irreversible death of brain tissue, blood flow must be restored as quickly as possible. Persons must therefore be familiar with the signs and symptoms of a stroke so they can access and receive immediate medical attention. The symptoms of a stroke can vary, depending upon which part of the brain is affected. It is important to realize that a stroke is not painful and generally does not cause a headache (the one exception is subarachnoid hemorrhage, which is discussed below).
Examples of common stroke symptoms include the following:
numbness on one side of the body (hemi-anesthesia)
weakness on one side of the body (hemiparesis)
difficulty with eyesight or vision
complete or partial loss of the visual field (vision to one side), which involves both eyes (hemianopia)
complete or partial loss of vision in one eye (amaurosis fugax)
double vision (diplopia)
the sensation of spinning (vertigo)
slurred speech (dysarthria)
disturbance of language functions (aphasia)
inability to express oneself, through both speech and writing (expressive aphasia, Broca's aphasia, non-fluent aphasia)
inability to comprehend what is being said or read (receptive aphasia, Wernicke's aphasia, fluent aphasia)
These symptoms can occur in isolation or in combination with each other. Recognition of these symptoms by the individual experiencing them or by family or friends should prompt an immediate 911 call for transport to the nearest emergency room.
Different Stroke Classes
The first step in treating a stroke is to identify whether the symptoms are caused by an ischemic stroke, which results from interruption of blood flow through an artery, or a hemorrhagic stroke, which results from bleeding in or around the brain, since the therapeutic interventions and prognosis differ dramatically. The distinction between the two major classes of stroke is made by doing a CT scan (a special x-ray test that produces images of thin cross sections of the body) of the head. In the case of a hemorrhagic stroke, blood may be seen in the brain tissue itself (intracerebral hemorrhage) or surrounding the brain (subarachnoid hemorrhage). In the case of subarachnoid hemorrhage, further evaluation is required to identify the source of bleeding, which is usually due to rupture of an aneurysm (an abnormality in the wall of a blood vessel). Aneurysmal subarachnoid hemorrhage is a neurosurgical emergency requiring immediate operative intervention.
Appropriate therapy for intracerebral hemorrhage is not clearly established, but may involve the placement of a catheter or fiber-optic device into the brain to measure the intracranial pressure (ICP). In some circumstances, surgery may be needed to remove the clot.
If a CT scan is done shortly after the onset of symptoms in ischemic stroke, it may reveal no abnormalities. Most hospitals now have the ability to do diffusion-weighted imaging (DWI) with an MRI scanner. A diffusion-weighted image will show abnormalities in the brain within minutes after the onset of symptoms. Ischemic strokes occur when a blood clot enters the cerebrovascular circulation and blocks an artery (embolic stroke), when a clot forms at the site of a diseased blood vessel (hrombosis), or when a small blood vessel occludes (closes) due to chronic hypertensive or diabetic injury (lacunar stroke).
Irrespective of the cause of an ischemic stroke, the most appropriate first therapy is aspirin. Two large studies show that for every 1,000 acute stroke patients treated with aspirin, approximately 10 deaths and bad outcomes can be prevented. The optimal dose of aspirin to use is not clear, but a standard 325-milligram tablet should suffice.
Tissue Plasminogen Activator (tPA)
The only therapy approved by the FDA proven to improve outcome in ischemic stroke, is tissue plasminogen activator (tPA), which is administered through a catheter placed in a vein (an IV). Other therapies have been proven to work, but have not yet been approved by the FDA.
Tissue plasminogen activator is a thrombolytic agent. Thrombolytics dissolve blood clots and thereby restore blood flow (and thus oxygen and glucose) to ischemic brain tissue. In order for tPA to be effective (and safe), it must be given within three hours of stroke onset. Practically speaking, this means that the stroke victim must arrive to the ER no later than two and a half hours after symptom onset in order for a history, examination, and necessary studies to be done. In order to receive tPA, the CT scan must be completed, interpreted, and show no signs of bleeding in or around the brain. Blood pressure must be adequately controlled to prevent bleeding into the brain.
Drugs like labetalol may be used to achieve predefined goals of a systolic blood pressure less than 185 mmHg and a diastolic blood pressure less than 110 mmHg. Blood studies need to be done in order to assure that there is nothing that would increase the risk of bleeding, such as a low platelet count (thrombocytopenia) or abnormal clotting tests (coagulopathy). People who take warfarin (Coumadin), which prolongs the clotting time, are not eligible to receive tPA. Because the most significant risk associated with tPA use is bleeding (either systemically or into the brain), recent major surgery is also a contraindication to receiving tPA.
tPA studies
The study that established the efficacy of tPA in acute stroke was sponsored by the National Institute of Neurological Disorders and Stroke (NINDS), a division of the National Institutes of Health (NIH). In this study, outcome from a stroke was assessed three months after its occurrence; 41 percent of people that received tPA experienced full or near full recovery from their stroke compared to 29 percent of people not receiving tPA. In those that received tPA, 6.4 percent suffered a worsening of their symptoms due to intracerebral hemorrhage, compared with 0.6 percent of patients who did not receive tPA. The risk of intracerebral hemorrhage increases with the severity of stroke and with abnormalities referable to the stroke on the initial CT scan.
Despite the increase in intracerebral hemorrhage with tPA use, there was a non-significant trend towards decreased mortality in people treated with tPA (17 percent vs. 21 percent).
There have been two European Cooperative Acute Stroke Studies (ECASS I and ECASS II) that have failed to show a benefit to tPA therapy in stroke. The major difference between the ECASS studies and the NINDS study is the time window for therapy. In ECASS, patients were treated up to six hours after symptom onset; in NINDS, therapy commenced within three hours of symptom onset. Atlantis, another North American study, addressed the benefit of tPA therapy given three to five hours following symptom onset; no benefit was seen. Thus, it is very clear that intravenous tPA must be given within three hours of symptom onset to be of benefit.
Thrombolytics studies
Thrombolytics can also be administered through a catheter positioned in an artery at the site of occlusion.
Local or intra-arterial infusion of a thrombolytic agent theoretically decreases the risk of hemorrhage because the effect of the agent is concentrated at the site of infusion. One study (PROACT) suggests that patients with closure the middle cerebral artery can benefit from intra-arterial therapy if it is started within six hours of symptom onset. Occlusion of the basilar artery, the vessel that provides circulation to the brainstem, carries a grave prognosis with a mortality rate of almost 85 percent. Because of its deadly nature, intra-arterial thrombolysis is frequently done for patients with strokes due to occlusion of the basilar artery. While there are anecdotal reports of its efficacy, the benefit of intra-arterial thrombolysis for basilar artery occlusion remains unproven. The major limitation to intra-arterial therapy is time. Very few hospitals have the capability of providing intra-arterial therapy, which requires a skilled interventional neuroradiologist, and even in hospitals where intra-arterial therapy is done routinely, it takes time to set up the angiographic suite and perform the procedure
Most studies done since the approval of tPA for stroke by the Food and Drug Administration (FDA) support the findings of the NINDS study, and administration of intravenous tPA for an acute ischemic stroke is now considered standard of care. Unfortunately, very few patients (approximately 5 percent) actually receive the drug. Failure to receive tPA is generally related to the fact that very few people who have had strokes actually make it to the hospital in time to qualify for therapy. There are many reasons for the delay to a hospital evaluation in stroke patients. Studies reveal that most people don't know the signs and symptoms of a stroke (or even that a stroke involves the brain) and therefore fail to correctly interpret their symptoms. People often deny the significance of their symptoms and wait to see if they will go away. Finally, failure to call 911, due to embarrassment or other concerns, results in a significant delay to evaluation. A somewhat trite, but very accurate saying is, "Time is Brain." Indeed, with every minute that passes, the chance of intervening in a meaningful way slips away.
Post-Stroke Conditions
With the exception of aspirin and tPA, no other therapies have been demonstrated to improve outcome in stroke. There are other stroke treatment strategies, however, that seem intuitive and should be part of routine practice.
For instance, while hypertension is the leading risk factor for stroke, hypertension that occurs in the face of acute stroke shouldn't be treated. Normally, the amount of blood flow to the brain remains constant, irrespective of the blood pressure, a concept known as autoregulation. In the case of a stroke, however, the amount of cerebral blood flow is determined by the blood pressure. Most individuals develop hypertension at the time of a stroke, even if they have no prior history of hypertension. The elevation in blood pressure, in part, reflects a compensatory mechanism of the brain to improve blood flow. While patients who receive tPA are required to have their blood pressure treated to the parameters mentioned previously, patients not receiving tPA should be allowed to be hypertensive in the acute phase of their strokes-approximately three days.
Hyperglycemia
Persons with stroke will often develop hyperglycemia (elevated blood glucose). While diabetes mellitus is a risk factor for stroke, the hyperglycemic response in acute stroke appears to be independent of a prior history of diabetes. Post-stroke hyperglycemia may represent a stress response to the stroke, but it also appears to contribute to brain damage. In addition, hyperglycemia predisposes to brain hemorrhage in patients receiving tPA, and may even increase the risk of intracerebral hemorrhage in persons not receiving tPA. While no clear guidelines for the management of hyperglycemia in stroke have been established, hyperglycemia should probably be treated aggressively (less than 140 mg/dl).
Fever
Fever is also common following stroke. Like hyperglycemia, fever may reflect a stress response to the stroke itself, but likely contributes to ischemic brain injury. Fever increases the metabolic rate and oxygen consumption of the brain, thereby increasing the mismatch between the oxygen supply and demand that already exists in stroke. Fever also appears to increase the release of excitotoxic amino acids (amino acids that are normally found in the brain but can cause injury if present in high concentrations) and enhances the inflammatory response in the brain, both of which may promote further brain injury. Thus, fever should be prevented with drugs such as acetaminophen (Tylenol) and ibuprofen. Cooling blankets should be used if needed. Induced cooling to body temperatures lower than normal (hypothermia) is currently being explored as a therapy for stroke as well as other types of brain injury.
Conclusion
Over the past years, there has been an explosion in knowledge about how the brain works and how it responds to injury, like ischemia and hypoxia.
Drugs, or neuroprotective agents, have been developed to interfere with the cellular events that occur following an ischemic or hypoxic insult. In the laboratory setting, these drugs appear to be highly effective at reducing brain injury even when blood flow can't be restored. Unfortunately, none of these drugs have been shown to reduce brain injury or improve outcome from stroke when tested in people. Understanding why the clinical trials of neuroprotective agents are overwhelmingly negative in the face of repeatedly positive laboratory studies is now a priority in stroke research. The one thing that is clear, however, is that whatever is to be done to lessen the injury in stroke needs to be done soon after its onset.
Effective therapies for acute stroke are limited, and the best treatment for stroke remains prevention. If one does experience a stroke, it is imperative to get to the hospital as soon as possible in order to benefit from interventions that can improve outcome.
