A stroke is an acute medical emergency caused by interruptions to the blood supply in the brain, which are caused by blockages in brain arteries or hemorrhages. Patients with high blood pressure, diabetes and unsafe cholesterol levels are at increased risk of stroke, as are the elderly. Symptoms of a stroke include dizziness, loss of balance, paralysis on one side of the body, vision disruptions, and an inability to speak. A patient experiencing these symptoms should seek immediate medical attention. While the effects of stroke can be limited if the episode is not severe, strokes can result in permanent disability or death.