Strokes

Strokes are a medical condition that occurs when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients. Strokes are a major cause of death and disability worldwide.

Causes

Strokes can be caused by a blocked artery (ischemic stroke) or the leaking or bursting of a blood vessel (hemorrhagic stroke). Some people may experience only a temporary disruption of blood flow to the brain (transient ischemic attack, or TIA) that doesn't cause permanent damage.

Ischemic stroke

Ischemic strokes are the most common type of stroke. They occur when the arteries to your brain become narrowed or blocked, causing severely reduced blood flow (ischemia). The most common ischemic strokes include:

• Thrombotic stroke: A thrombotic stroke occurs when a blood clot (thrombus) forms in one of the arteries that supply blood to your brain.
• Embolic stroke: An embolic stroke occurs when a blood clot or other debris forms away from your brain — commonly in your heart — and is swept through your bloodstream to lodge in narrower brain arteries.

Hemorrhagic stroke

Hemorrhagic stroke occurs when a blood vessel in your brain leaks or ruptures. Brain hemorrhages can result from many conditions that affect your blood vessels, including uncontrolled high blood pressure (hypertension) and weak spots in your blood vessel walls (aneurysms).

Symptoms

The symptoms of stroke include trouble with walking, speaking, and understanding, as well as paralysis or numbness of the face, arm, or leg. Because stroke occurs rapidly and requires immediate treatment, knowing the signs can be of vital importance.

Treatment

Treatment for stroke depends on whether it's ischemic or hemorrhagic. Treatment for ischemic stroke may include medications to prevent blood clots and strokes, and a procedure to remove the clot. Hemorrhagic stroke treatment involves surgery to repair the damage.

Prevention

Prevention includes controlling high blood pressure, quitting tobacco use, managing diabetes, and treating obstructive sleep apnea.

See also

• Heart disease
• Hypertension
• Aneurysm