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A Better Understanding of Stroke
2/5/2009 12:00:00 AM (MST)
A Better Understanding of Stroke
Your brain is an amazing organ. Its nerve cells are always sending signals to one another and throughout your body, telling your mouth to form words, your feet to move or your eyes to focus.
During a stroke, the brain cells that send these signals may die because blood isn?t getting to them. Consequently, you may lose the ability to talk, move or even think clearly.
Fast action can help minimize the damage done by a stroke, says the American Heart Association (AHA). A stroke is a medical emergency. That?s why some doctors call strokes ?brain attacks.? Call 911 or your local emergency number if you notice the sudden appearance of any of these symptoms:
Numbness or weakness in the face, arms or legs, often affecting only one side of the body
Trouble speaking or understanding what others are saying
Problems seeing with one or both eyes, or sudden double vision
Loss of balance, dizziness or difficulty walking
Severe headache that comes on suddenly with no known cause
The two main types of stroke?ischemic and hemorrhagic?may share symptoms, but the causes and treatments aren?t the same. Successful treatment depends on differentiating between the two.
Ischemic stroke
This type of stroke occurs when a blood vessel in or near the brain becomes blocked, the AHA says. Without blood bringing oxygen and nutrients to brain cells, they may stop functioning and die. Depending on the area of the brain that?s affected, a stroke may impair your ability to speak, walk, see or think clearly. About 80 percent of all strokes fall into this category.
Atherosclerosis is a common cause of ischemic stroke. It occurs when fatty deposits, or plaques, accumulate on blood vessel walls. Eventually, the plaques may build up enough to block blood flow. Or, blood clots may form where the blood vessel narrows. A clot that develops where the blockage occurs is a thrombus. These clots cause most strokes. An embolism is a clot that usually starts in a larger blood vessel?such as the carotid artery?breaks free and flows with the blood until it clogs a smaller blood vessel. Heart rhythm disorders, such as atrial fibrillation, may cause clots to form in the heart chambers. If one of these clots breaks free, it can travel to the brain and cause a stroke.
Medication can help dissolve clots and restore blood flow. But, you need to receive it within three hours of when symptoms begin. The longer it takes to restore blood circulation, the more damage may be done. Rarely, surgery also may be necessary. A blood thinner, such as aspirin or warfarin, may be recommended to help prevent future clots and another stroke.
Transient ischemic attack (TIA)
Up to 25 percent of strokes are signaled by one of these ?warning strokes.? Symptoms are the same as those of a stroke, but they last less than 24 hours. Approximately 75 percent of TIAs last less than five minutes. A TIA can occur days or months before a major stroke does, but risk of stroke is highest within 48 hours of a TIA, the AHA says. That?s why it?s important to seek immediate medical care for a possible TIA.
Hemorrhagic stroke
Burst blood vessels account for approximately 20 percent of all strokes, the AHA says. When blood spills into or around the brain, it puts pressure on cells in the area. If this pressure isn?t relieved quickly, brain cells may die.
High blood pressure, aging, diabetes, and smoking can weaken vessels and lead to an aneurysm. This is a ballooning weak spot in the wall that makes the blood vessel more likely to rupture. A head injury also may cause bleeding in the brain and a stroke.
Giving clot-busting drugs to someone with a hemorrhagic stroke can worsen bleeding. Instead, surgery may be needed to fix damaged vessels and remove blood in the brain. Medication to help control bleeding may be used, too.
Stroke recovery
What the future holds after a stroke depends on which part of the brain was affected and how much it was damaged. About 10 percent of those who survive a stroke regain most or all function. Half can live at home with medical assistance. An additional 40 percent need long-term care in a facility.
How fully you recover also depends on the type of stroke.
?For people who survive hemorrhagic stroke, recovery often is better than it is for those with a similarly severe ischemic stroke,? says Alexander Dromerick, M.D., associate professor of neurology at Washington University.
Once the blood is removed, the affected brain cells still may function somewhat. But, brain cells that die during an ischemic stroke don?t grow back.
?People who?ve had [a stroke] may experience lots of changes that affect their daily lives," says physical therapist Carolyn Baum, Ph.D., OTR/L. "But, appropriate medical care and occupational therapy may help them resume doing the things that are important in their lives."
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