A stroke produces sudden brain damage due to a disturbance of the brain’s blood supply. The most common type (called an ischemic stroke) is due to blockage of an artery supplying the brain, caused by a clot.
A stroke can also be caused by bleeding in the brain—due, for example, to a ruptured balloonlike swelling in a blood vessel (which is called an aneurysm).
This is known as a hemorrhagic stroke.
Risk factors for a stroke include high blood pressure, not getting enough exercise, an unhealthy diet, smoking, and disorders such as hyperlipidemia (high levels of fat in blood), diabetes, and certain heart conditions.
Typical symptoms are facial weakness, which may cause drooping of the face, mouth, or eye on one side; weakness or numbness of the arms; and speech problems, such as slurred speech.
A severe stroke may cause unconsciousness and coma, which may be life-threatening. A stroke requires urgent medical help.
Treatment varies according to the type of stroke. Some people make a good recovery, but many are left with long-term problems.