Causes of Stroke: Why Stroke Happens in Adults

Sudden weakness in an arm, a smile that droops on one side, slurred speech — the brain stops receiving blood, and cells begin to die within minutes. The cause of a stroke is always the same: disruption of blood supply to an area of the brain. But why this happens depends on the type of stroke.

What Happens in the Brain During a Stroke

A stroke is an acute disruption of blood supply to the brain with the sudden onset of neurological symptoms that persist for more than 24 hours or lead to death sooner. Without oxygen and nutrients, brain cells die, and this threatens permanent brain damage, long-term disability, and death. There are two main types: ischemic, in which a clot blocks a vessel, and hemorrhagic, in which a vessel ruptures and blood enters the brain. Ischemic strokes account for about 80% of all cases.

Causes of Ischemic Stroke

Ischemic stroke develops when the arteries supplying the brain narrow or become blocked. A clot may form at the site of an atherosclerotic plaque or come from the heart in atrial fibrillation and other heart diseases. Atherosclerosis is called the main cause of stroke. A transient ischemic attack, or mini-stroke, is distinguished separately: blood flow is blocked briefly, cell damage is not permanent, but a prior TIA sharply increases the risk of a true stroke.

Causes of Hemorrhagic Stroke

Hemorrhagic stroke occurs when a vessel ruptures and bleeds into the brain. Its causes include high blood pressure, an aneurysm (a bulging vessel), and an arteriovenous malformation, a tangle of improperly formed arteries and veins. Hemorrhages account for 20–25% of stroke cases.

Main Risk Factors for Stroke

Stroke risk may be increased in people over 50 years of age, as well as in people of Black or South Asian origin. Incidence rises noticeably with age: 95% of strokes occur after age 45. Among the conditions that increase risk are arterial hypertension (the main factor), diabetes mellitus, atrial fibrillation, high cholesterol, and a prior TIA. Lifestyle, smoking, alcohol, excess weight, and low physical activity also play a role.

• High blood pressure
• Diabetes mellitus and heart disease, including atrial fibrillation
• Smoking, alcohol, and illicit drug use
• High cholesterol, unhealthy diet, obesity
• Prior transient ischemic attack or stroke in the past

Why Stroke Happens in Young People

A stroke can occur at any age. In young people, the cited causes include sickle cell disease, migraines, use of combined contraceptives, as well as pregnancy with preeclampsia and recent childbirth. The causes of stroke in men and in women remain the same diseases and habits, and mortality is higher in men.

When Emergency Help Is Needed for Suspected Stroke

Stroke symptoms usually appear suddenly. These are numbness or weakness of the face, arm, or leg, especially on one side, confusion and difficulty speaking, vision problems, impaired gait and balance, and a severe headache without cause. The FAST test is used for recognition: face, arm, speech, time. The diagnosis is confirmed with a CT or MRI of the brain and cardiac examinations, including ECG and echocardiography.

Call 103 or 112 immediately if a person suddenly has a drooping corner of the mouth, weakness in an arm or leg, slurred speech, confusion, loss of vision, impaired balance, or a very severe headache without cause. Every minute matters.

This article is for reference; it helps you understand why stroke happens but does not replace a doctor's consultation: only a specialist can assess your personal risk.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer