Stroke
A stroke is a medical emergency in which blood flow to part of the brain is blocked or a blood vessel breaks, causing brain cells to lose oxygen and nutrients.
What a stroke is
A stroke happens when part of the brain suddenly loses the blood flow it needs or when bleeding disrupts brain tissue. Because blood carries oxygen and nutrients, affected brain cells can begin to die quickly. The effects depend on which part of the brain is injured and how much tissue is involved.
Ischemic and hemorrhagic strokes
Most strokes are ischemic, meaning a clot or narrowed blood vessel blocks blood flow to brain tissue. Hemorrhagic strokes happen when a blood vessel breaks and blood leaks into or around the brain. The distinction matters because treatments differ: a clot-busting or clot-removal approach can help some ischemic strokes, while bleeding strokes require controlling bleeding, pressure, and the underlying cause.
Warning signs
Stroke symptoms usually appear suddenly. Warning signs include face drooping, arm weakness, speech trouble, confusion, trouble seeing, dizziness, loss of balance or coordination, trouble walking, or a severe headache with no known cause. The FAST memory aid highlights Face, Arms, Speech, and Time to call emergency services.
What to do
If stroke is possible, call emergency services immediately. Do not wait to see if symptoms pass, and do not drive yourself or someone else instead of calling an ambulance. Note the time symptoms began or when the person was last known well, because that timing helps clinicians decide which emergency treatments may be safe and useful.
Diagnosis and acute treatment
Emergency teams assess symptoms, neurological function, blood pressure, medicines, and medical history. CT or MRI imaging helps identify bleeding, blockage, and the affected brain area. Treatment may include clot-dissolving medicine, procedures to remove a clot, blood-pressure control, surgery or procedures for bleeding or aneurysm, and close monitoring in a stroke unit.
Recovery and rehabilitation
Recovery can involve physical therapy, occupational therapy, speech-language therapy, swallowing care, vision support, mood care, and help with memory or attention changes. Some abilities return quickly, while others improve gradually through practice and adaptation. Family education matters because stroke can change communication, movement, emotions, fatigue, and independence.
Risk and prevention
Important risk factors include high blood pressure, diabetes, heart disease, atrial fibrillation, smoking, high cholesterol, prior stroke or transient ischemic attack, physical inactivity, unhealthy diet, older age, and some family or social risk patterns. Prevention can include blood-pressure control, not smoking, physical activity, heart-healthy eating, medicine when prescribed, and managing heart rhythm or artery disease.
Why it matters
Stroke matters because it is both common and time-sensitive. Public recognition of warning signs can change outcomes before a specialist ever sees the patient. Prevention also has a broad reach: the same choices and treatments that reduce stroke risk can often reduce risk for heart disease, kidney disease, dementia, and other long-term health problems.