A stroke happens when part of the brain is injured because blood flow is blocked or because bleeding occurs in or around the brain. Stroke is a medical emergency.

Common warning signs

Warning signs can include face drooping, arm weakness, speech trouble, sudden confusion, vision changes, severe dizziness, loss of balance, or a sudden severe headache.

Why fast action matters

Brain cells can be damaged quickly when oxygen and blood flow are interrupted. Emergency care can reduce damage and may offer time-sensitive treatments.

High blood pressure, atrial fibrillation, diabetes, smoking, high cholesterol, and some blood vessel problems can increase stroke risk.