History of Stroke Hippocrates, the father of medicine, first recognized stroke over 2,400 years ago. At this time stroke was called apoplexy, which means "struck down by violence" in Greek. Overview of Stroke Stroke occurs when blood flow to the brain is disrupted. The disruption is caused when either a blood clot or piece of plaque blocks one of the vital blood vessels in the brain or when a blood vessel in the brain bursts. Types of Stroke Strokes are classified as either ischemic or hemorrhagic. Ischemic strokes are caused by blockage of an artery. Hemorrhagic strokes are caused by bleeding in the brain. Stroke Stroke occurs when blood flow to the brain is disrupted. A blood clot can block one of the vital blood vessels in the brain or a blood vessel in the brain can burst, spilling blood into surrounding tissues. Subarachnoid Hemorrhage An aneurysm is a weakened area in a blood vessel that’s at risk of bursting. A subarachnoid hemorrhage means that there is bleeding in the space that surrounds the brain. Most often, it occurs when an aneurysm that's located on the outer surface of the brain bursts and leaks blood around the brain and inside the skull. What Is a Transient Ischemic Attack? A transient ischemic attack (TIA), also called a ministroke or warning stroke, causes symptoms similar to those of a stroke. Statistics of Stroke Almost every 40 seconds in the United States, a person experiences a stroke.