Ischemic strokes happen when a blood clot blocks a vessel and cuts off blood flow. Hemorrhagic strokes occur when a blood vessel ruptures, leaking blood into brain tissue and raising pressure inside the skull. One is obstruction, the other is rupture.
An ischemic stroke is caused by a lack of blood flow to an area of the brain because there's a blood clot that blocks that blood flow. A hemorrhagic stroke is when a blood vessel breaks and blood is leaking out of that vessel, which leads to two problems. A lack of blood flow to the designated area and an increase in intracranial pressure, since the blood is leaking out of the vessel, increasing the pressure in the brain. So in an ischemic stroke, there's an actual clot that cuts off blood flow. But in a hemorrhagic stroke, the blood vessel breaks and blood is now leaking out around the brain.
