Ischemic stroke is caused by an interruption of blood flow to the brain. Hemorrhagic stroke is caused by bleeding inside the head. Doctors call this area of dead cells an infarct. Over hours, this chain reaction endangers brain cells in a progressively larger area of brain where blood supply is compromised but not completely cut off. Immediate medical care is critical.
New treatments work only if given within a few hours after the onset of a stroke.
For example, a clot-busting drug must be given within three hours. Before treatment, the neurologist or emergency physician must carefully examine the patient to determine the patient's condition and what caused the stroke. Once the doctor completes these tests, the treatment is selected. For all stroke patients, the aim is to prevent further brain damage. The disability depends on the size and location of the stroke.