Stroke Signs & Symptoms
A stroke occurs when part of the brain is suddenly deprived of blood because of a narrowed, blocked, or ruptured blood vessel. When blood fails to reach any part of the brain, brain cells die from a lack of oxygen and nutrients. As a result, the functions controlled by those brain cells become impaired or lost.
Stroke can cause various symptoms depending on the part of the brain that was affected. Stroke symptoms are usually sudden and may include paralysis or weakness on one side of the body, numbness or tingling, difficulty speaking or understanding, visual impairment, imbalance, or clumsiness. Headache with such symptoms may indicate that the stroke is a result of rupture of an artery in the brain, bleeding from which creates a rapid increase in pressure within the head.
Diagnosing & Treating Stroke
There are two different kinds of stroke – Ischemic and Hemorrhagic. Doctors review imaging studies of the brain to determine the type of stroke and best course of therapy.
A transient ischemic attack is often a warning sign of stroke. This occurs when blood flow to part of the brain is temporarily reduced or blocked, often caused by a blood clot. Symptoms of a TIA are the same as a stroke, however, after a few minutes, blood flow is restored and the symptoms do go away without significant or any permanent damage. With a stroke, the damage to the brain can be permanent because the blood flow is not restored.
Most strokes (approximately 83%) are ischemic, caused by a blood clot that blocks or limits blood flow to the brain. Doctors treat this kind of stroke by removing the clot blocking blood flow to the brain. The most promising treatment for ischemic stroke is the FDA-approved clot-busting drug tPA, which must be administered within a 3-hour window from the onset of symptoms to work best. Generally, however, just 3 to 5 percent of those who suffer a stroke reach the hospital in time to be considered for this treatment. In many cases, advanced treatments and clinical trials can extend the window of time for effective treatment to 8 hours or more.
*Hemorrhagic (bleeding) strokes
About 20 percent of strokes are called hemorrhagic or bleeding strokes and occur when a blood vessel weakens and ruptures. Clot busters cannot be used in hemorrhagic strokes because they can increase dangerous bleeding in the brain. Hemorrhagic or bleeding strokes usually result from a rupturing aneurysm or arteriovenous malformation (AVM, or an abnormality in the vessels to the brain). Surgical intervention is usually recommended to either clamp the base of the aneurysm or remove the abnormal vessels comprising an AVM.
Some patients benefit from a clot-dissolving therapy (tPA) when it is administered within three hours of the onset of stroke; however, not all patients are eligible for this treatment, or they may arrive at a hospital too late for standard treatments. In some cases, the hospital may lack the specialists, equipment and organization to effectively treat them in time.
Sarasota Memorial’s advanced endovascular techniques – which are not available at many other hospitals – can extend the emergency treatment window to eight hours or more after a stroke begins. People who miss the 3-hour window of treatment or who are ineligible for IV tPA due to other circumstances may still benefit from specialized tools and minimally invasive techniques to extract dangerous blood clots in the brain, clear its delicate blood vessels of blockages and repair other cerebrovascular abnormalities.