A medical condition where poor blood flow to the brain causes cell death.A stroke is a medical emergency in which the blood supply to part of the brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients. Within minutes, brain cells begin to die, which can lead to lasting brain damage, disability, or death. It is one of the leading causes of death and long-term disability worldwide, and it can happen to anyone at any age, though risk increases with certain conditions like high blood pressure, diabetes, and smoking.
The condition has been recognized since antiquity, but the modern understanding of stroke as a vascular event emerged in the 17th century with Thomas Willis, who described its anatomy and coined the term 'apoplexy.' The distinction between ischemic and hemorrhagic strokes was clarified in the 19th and 20th centuries with advances in pathology and imaging.
The brain relies on a constant flow of blood to deliver oxygen and glucose. When a blood vessel in the brain is blocked by a clot (ischemic stroke) or bursts (hemorrhagic stroke), the downstream tissue is starved. Without energy, neurons fail to maintain their ion gradients, leading to a cascade of cellular damage, swelling, and cell death. The extent of damage depends on how long the blood flow is interrupted and which brain region is affected.
Stroke care relies on rapid diagnosis and treatment, such as clot-busting drugs (tPA) or mechanical thrombectomy, to restore blood flow and minimize brain damage. Preventive strategies include managing blood pressure, cholesterol, and atrial fibrillation.
The phrase 'brain attack' is used by some medical professionals to emphasize that a stroke is as urgent as a heart attack, because 'time is brain' — every minute without treatment, about 1.9 million neurons are lost.