What is a stroke? Symptoms, causes, risks and more

Someone has a stroke every 40 seconds in the U.S., according to the Centers for Disease Control and Prevention. The risk increases as people get older, but strokes can happen at any age.

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What is a stroke?

Also called a “brain attack,” a stroke happens when blood flow to an area of the brain is blocked or if there is sudden bleeding in the brain.

What happens during a stroke?

It depends on the type:

• An ischemic stroke is caused by a blood clot or plaque that blocks a blood vessel in the brain. About 87 percent of all strokes are this type, according to the CDC.
• A hemorrhagic stroke is caused by a blood vessel that bursts and bleeds into the brain.

Brain cells can be damaged or die within minutes, causing symptoms in the parts of the body they control. A stroke is a medical emergency. It can cause brain damage, long-term disability and death.

Recent guidelines have expanded the "golden window" when doctors can minimize or prevent permanent stroke damage with clot removal and treatments from six to 24 hours.

What is the main cause of stroke?

High blood pressure, high cholesterol, smoking, obesity, and diabetes are leading causes of stroke, according to the CDC.

How can you tell is someone is having a stroke?

A good acronym to remember is FAST, according to the American Stroke Association:

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• Face drooping: Ask the person to smile – is the smile uneven? Is one side of the face numb?
• Arm weakness: Ask the person to raise both arms. Is one arm weak or numb?
• Speech: Is the person slurring words, not able to speak at all or hard to understand?
• Time to call 911: If the person shows any of these symptoms, call for help.

What are the early warning signs of a stroke?

A “mini stroke,” also known as a transient ischemic attack, is often a precursor to a major stroke, occurring a few days before or on the day of the main attack. It happens when the blood supply to the brain is briefly interrupted and lasts a few minutes.

But strokes often happen without warning. Symptoms include:

• sudden numbness, especially on one side of the body
• confusion or trouble speaking
• trouble seeing in one or both eyes
• sudden difficulty walking
• sudden severe headache

What are the first signs of a mini stroke?

The symptoms of a mini stroke are similar to regular stroke symptoms, but don’t last as long. They also happen suddenly.