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Learn About Stroke Types, Causes, Symptoms, and Diagnosis

In the United States, stroke affects more than 750,000 people each year. It's the leading cause of adult disability and is the fifth-leading cause of death.

On this page:

The Three Types of Stroke

The different types of stroke include:

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Stroke Causes

A stroke most often occurs when blood flow to the brain becomes blocked (called ischemic stroke).

One of the following problems may cause this blockage:

  • A build-up of fatty substances (atherosclerotic plaque) along an artery's inner lining causes it to narrow, reduces its elasticity, and decreases its blood flow.
  • A clot forms in an artery supplying blood to the brain.
  • A clot forms somewhere in the body — often the heart — and breaks free, traveling to an artery supplying blood to the brain and becoming lodged there.

A stroke also may occur if a blood vessel breaks and bleeds into or around the brain. If this happens, it is called a hemorrhagic stroke.

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Stroke Symptoms

If you suspect someone is having a stroke, watch for these common warning signs:

  • One-sided weakness
  • Numbness on one side of face, arm, or leg
  • Slurred or garbled speech
  • Difficulty talking to or understanding others
  • Loss of vision or difficulty seeing in one eye
  • Double vision
  • Difficulty with balance or coordination of arms or legs
  • Severe headache (the worst headache of your life)

It’s important to call 911 immediately at any sign of a stroke.

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Diagnosing Stroke

Tests that help doctors diagnose stroke include:

  • Neurological exams
  • Blood tests
  • Other tests to quickly determine the cause, location, and amount of damage

Imaging scans that can help diagnose stroke include:

  • Computed tomography (CT) scan — a type of x-ray that uses a computer to make pictures of the brain.
  • Magnetic resonance imaging (MRI) scan— a test that uses magnetic waves to make pictures of the brain.
  • Arteriography (angiography) — shows arteries in the brain.
  • Magnetic resonance angiography (MRA) — creates a of blood flow& in the brain's vessels.
  • Functional MRI — shows brain activity by picking up signals from oxygenated blood.
  • Doppler ultrasound — reveals narrowing of the arteries supplying blood to the brain.

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Stroke Resources

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