A stroke occurs when the blood supply to part of your brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients. Brain cells begin to die in minutes.
A stroke is a medical emergency, and prompt treatment is crucial. Early action can reduce brain damage and other complications.
The good news is that many fewer Americans die of stroke now than in the past. Effective treatments can also help prevent disability from stroke.
If you or someone you're with may be having a stroke, pay particular attention to the time the symptoms began. Some treatment options are most effective when given soon after a stroke begins.
Signs and symptoms of stroke include:
Trouble speaking and understanding what others are saying. You may experience confusion, slur your words or have difficulty understanding speech.
Paralysis or numbness of the face, arm or leg. You may develop sudden numbness, weakness or paralysis in your face, arm or leg. This often affects just one side of your body. Try to raise both your arms over your head at the same time. If one arm begins to fall, you may be having a stroke. Also, one side of your mouth may droop when you try to smile.
Problems seeing in one or both eyes. You may suddenly have blurred or blackened vision in one or both eyes, or you may see double.
Headache. A sudden, severe headache, which may be accompanied by vomiting, dizziness or altered consciousness, may indicate that you're having a stroke.
Trouble walking. You may stumble or lose your balance. You may also have sudden dizziness or a loss of coordination.
When to see a doctor
Seek immediate medical attention if you notice any signs or symptoms of a stroke, even if they seem to come and go or they disappear completely. Think "FAST" and do the following:
Face. Ask the person to smile. Does one side of the face droop?
Arms. Ask the person to raise both arms. Does one arm drift downward? Or is one arm unable to rise?
Speech. Ask the person to repeat a simple phrase. Is his or her speech slurred or strange?
Time. If you observe any of these signs, call 911 or emergency medical help immediately.
Call 911 or your local emergency number right away. Don't wait to see if symptoms stop. Every minute counts. The longer a stroke goes untreated, the greater the potential for brain damage and disability.
There are two main causes of stroke: a blocked artery (ischemic stroke) or leaking or bursting of a blood vessel (hemorrhagic stroke). Some people may have only a temporary disruption of blood flow to the brain, known as a transient ischemic attack (TIA), that doesn't cause lasting symptoms.
This is the most common type of stroke. It happens when the brain's blood vessels become narrowed or blocked, causing severely reduced blood flow (ischemia). Blocked or narrowed blood vessels are caused by fatty deposits that build up in blood vessels or by blood clots or other debris that travel through your bloodstream and lodge in the blood vessels in your brain.
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. Factors related to hemorrhagic stroke include:
Uncontrolled high blood pressure
Overtreatment with blood thinners (anticoagulants)
Bulges at weak spots in your blood vessel walls (aneurysms)
Trauma (such as a car accident)
Protein deposits in blood vessel walls that lead to weakness in the vessel wall (cerebral amyloid angiopathy)
Ischemic stroke leading to hemorrhage
A less common cause of bleeding in the brain is the rupture of an abnormal tangle of thin-walled blood vessels (arteriovenous malformation).
Many factors can increase your stroke risk. Potentially treatable stroke risk factors include:
Lifestyle risk factors
Being overweight or obese
Heavy or binge drinking
Use of illegal drugs such as cocaine and methamphetamine
Medical risk factors
High blood pressure
Cigarette smoking or secondhand smoke exposure
Obstructive sleep apnea
Cardiovascular disease, including heart failure, heart defects, heart infection or abnormal heart rhythm, such as atrial fibrillation
Personal or family history of stroke, heart attack or transient ischemic attack
Age — People age 55 or older have a higher risk of stroke than do younger people.
Race — African Americans have a higher risk of stroke than do people of other races.
Sex — Men have a higher risk of stroke than women. Women are usually older when they have strokes, and they're more likely to die of strokes than are men.
Hormones — Use of birth control pills or hormone therapies that include estrogen increases risk.