Stroke, also known as cerebrovascular accident (CVA), cerebrovascular insult(CVI), or brain attack, is when poorblood flow to the brain results in cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. They result in part of the brain not functioning properly.Signs and symptoms of a stroke may include aninability to move or feel on one side of the body, problems understanding orspeaking, feeling like the world is spinning, or loss of vision to one sideamong others.Signs and symptoms often appear soon after the stroke has occurred. If symptoms last less than one or two hours it is known as atransient ischemic attack (TIA).Hemorrhagic strokes may also be associated with a severe headache.The symptoms of a stroke can be permanent. Long term complications may include pneumonia or loss of bladder control.

The main risk factor for stroke is high blood pressure.Other risk factors include tobacco smoking, obesity, high blood cholesterol, diabetes mellitus, previous TIA, and atrial fibrillationamong others. An ischemic stroke is typically caused by blockage of a blood vessel. A hemorrhagic stroke is caused by bleeding either directly into the brain or into the space surrounding the brain.Bleeding may occur due to a brain aneurysm. Diagnosis is typically with medical imaging such as acomputerized axial tomography (CT) scan or magnetic resonance imaging(MRI) scan along with a physical exam. Other tests such as anelectrocardiogram (ECG) and blood tests are done to determine risk factors and rule out other possible causes. Low blood sugar may cause similar symptoms.

Prevention includes decreasing risk factors as well as possibly aspirin,statins, surgery to open up the arteries to the brain in those with problematicnarrowing, and warfarin in those withatrial fibrillation.A stroke often requires emergency care.An ischemic stroke, if detected within three to four and half hours, may be treatable with a medication that can break down the clot. Aspirin should be used. Some hemorrhagic strokes benefit fromsurgery. Treatment to try recover lost function is called stroke rehabilitationand ideally takes place in a stroke unit; however, these are not available in much of the world.