Stroke is when poor blood flow to the brainresults 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 an inability to move or feel on one side of the body, problems understanding or speaking, feeling like the world is spinning, or loss of vision to one side among 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 a transient 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 fibrillation. 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 a computerized axial tomography (CT) scan or magnetic resonance imaging (MRI) scan along with a physical exam. Other tests such as an electrocardiogram (ECG) and blood tests are done to determine risk factors and rule out other possible causes. Prevention includes decreasing risk factors as well as possibly aspirin, statins, surgery to open up the arteries to the brain in those with problematic narrowing, and warfarin in those with atrial fibrillation. A stroke often requires emergency care.