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"Time is Brain": Treating Stroke as an Emergency
Dr. Campbell is Assistant Professor of Medicine, Department of Neurology, University of Texas Medical School at Houston.
If oxygen-rich blood is blocked from reaching the brain, brain nerve cells will die, producing damage and disability we call "stroke." Not too long ago, the treatment for most types of stroke was passive — wait for it to be over and then manage the consequences. With this approach, most stroke victims simply died. Those who survived faced the challenge of years of rehabilitation and, often, permanent brain damage or other disability. Today, however, there are several new treatments available that help to restore blood flow to the brain and, as a result, minimize damage.
What is a Stroke?A stroke happens when blood flow to the brain is blocked by a blood clot in a brain artery or because a brain blood vessel has burst. Obstruction is the more common cause. Stroke symptoms include headache, mental confusion, inability to speak, loss of consciousness and paralysis.
When a stroke occurs, part or all of the brain is deprived of oxygen. Without oxygen, affected nerve cells in the brain stop functioning and begin to die within minutes. This is a disaster for the body because dead brain cells cannot be replaced. Because the brain controls the rest of the body, the death of certain brain cells often means a loss of functioning elsewhere.
Stroke affects 700,000 people annually in the US. It is the third leading cause of death and the number one cause of long-term adult disability.
A New Treatment and TimetableIn 1996, stroke treatment changed dramatically when the FDA approved the use of a new drug called tissue plasminogen activator, or tPA, to treat stroke. tPA immediately dissolves the blood clots that cause many strokes, drasically reducing the amount of damage strokes produce. Since then, several other drugs have been developed that are similar to tPA. These include r-tPA, streptokinase, urokinase and prourokinase. Together they are known as thrombolytic drugs from the Ancient Greek word, thrombolysis, meaning "clot-dissolving."
Thrombolytics, however, only work if delivered directly into the bloodstream, either through a vein or an artery (intra-arterial). Both are complicated processes, especially intra-arterial treatment, which involves assembling a medical team and performing an elaborate test called cerebral angiography. Most importantly, these drugs must be administered within a few hours of the stroke before the oxygen-deprived nerve cells suffer permanent damage. Emergency rooms and emergency medical services have to work quickly because "time is brain." In other words, the faster stroke victims are treated, the less damage to the body and, especially, to the brain.
If a loved one or friend suffers a stroke, you need to make sure that he or she gets to the hospital as soon as possible. The time window for getting the best results from thrombolytic drugs is three hours from the first signs of stroke.
Treating Stroke with tPAThe FDA's approval of tPA in June 1996 was a major advance in stroke management.(1) tPA works by traveling through the bloodstream to the clot or other blockage; it then dissolves the material causing the obstruction and allows blood flow to resume. The result is that far less brain tissue is deprived of oxygen and victims suffer less damage. But tPA and other thrombolytics can cause increased bleeding. This is the reason that they are never used to treat strokes that result from burst blood vessels.
Studies demonstrated that patients given intravenous tPA within three hours of suffering a stroke were far better off three months afterward. Later studies showed that while 10-20% of all stroke victims could benefit from tPA, only 1-2% are actually getting it, or getting it in time.(2)(4)
Today, the medical community has been gradually adjusting to view stroke as a true emergency. As in any other profession, it has proven to be a difficult and frustrating task to change long-standing beliefs and attitudes. Extensive efforts are needed to educate medical professionals, from physicians to EMS personnel, as well as the general public, about stroke awareness.(5)
Part of the difficulty is that in order to provide state-of-the-art stroke treatment, hospital emergency rooms and stroke treatment centers need to build a multidisciplinary support network including emergency medicine, primary care, neurology and radiology. This requires a great deal of time, money and effort.(3)(6)(7)(8)
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