A stroke can lead to severe damage and even death. But what causes a stroke?

USA Today

24-04-2025

A stroke can lead to severe damage and even death. But what causes a stroke?
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Study: Low-calorie sweetener has been linked to risk of heart disease and stroke
A common zero-calorie sweetener could raise your risk for heart disease according to a new study. (Scripps News)
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People are understandably concerned when health conditions or infectious diseases that were once well-managed start increasing again, but proper education and advancements in medicine mean we often see the opposite. Declining rates of smoking, for instance, have led to far fewer people getting lung cancer. Ditto for the way serious cases of COVID-19 rapidly declined as the number of people who got vaccinated against the virus increased.
Despite still being the fifth leading cause of death in the United States, stroke is another example of an area we're seeing improvement. Data from U.S. Centers for Disease Control and Prevention show that far fewer Americans die of stroke today than in years past. This decrease is due, in part, to improvements in controlling major stroke risk factors such as high cholesterol and high blood pressure.
Significant improvements are still needed, however, as someone in the country is dying of stroke about every three minutes.
Here's what a stroke is, what causes it and what treatment usually looks like.
What is a stroke?
There are two main types of stroke. An ischemic stroke is what happens when something blocks the arteries or reduces blood flow from the heart to the brain. This blockage deprives brain tissue of vital oxygen and nutrients, which causes brain cells to die within minutes. Sometimes called a brain attack, a hemorrhagic stroke is caused by blood vessels in the brain bursting or leaking, which increases pressure on brain cells and kills or damages them. "About 85% of strokes are ischemic and about 15% are hemorrhagic," says Dr. Lawrence Wechsler, a professor of neurology at the University of Pittsburgh School of Medicine.
When brain cells are damaged in either way, it can cause difficulty seeing out of one or both eyes, numbness in the face, legs or arms (which usually manifests more on one side of the body than the other), a sudden and acute headache or slurred speech/difficulty talking. "General confusion or difficulty understanding speech can be another sign to look out for," says Dr. Jonathon Parker, a neurosurgeon at Mayo Clinic.
Some strokes are more severe than others, with people experiencing only mild confusion or a drooping smile while others can lose mobility or even consciousness. "The severity depends on which part of the brain is affected and how long the brain goes without blood flow – which is why some strokes can sadly be life-threatening," explains Dr. Rosy Thachil, director of the cardiovascular intensive care unit at NYC Health + Hospitals/Elmhurst.
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What causes strokes?
An ischemic stroke is caused by blood vessels becoming narrowed or arteries being blocked by fatty deposits. Other forms of blockage include "plaque buildup in the arteries or blood clots from the heart," says Wechsler.
The leaks and ruptures associated with a hemorrhagic stroke can be the result of any number of things that include head trauma, bulges at weak spots in blood vessel walls (known as aneurysms) or uncontrolled high blood pressure.
Many of these various causes are preventable or modifiable, explains Dr. John Hanna, a vascular neurologist for the Atlantic Health System in New Jersey. This is why risk factors such as obesity, smoking, excessive drinking and limited physical activity are all recommended against. Medical conditions such as type 2 diabetes, sleep apnea, high cholesterol and high blood pressure commonly increase one's risk of stroke and are also often within a person's control to reduce or avoid.
"Atrial fibrillation, which is a specific type of irregular heartbeat, can be another risk factor," adds Parker; and taking certain medications is yet another.
Two non-avoidable factors that predispose some individuals to vascular issues like stroke are getting older and genetics/a family history of heart disease, says Thachil.
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What is the best treatment for stroke?
It's critical to get medical treatment as soon as a stroke begins to improve recovery time and diminish or avoid longer-term damage, disability or death. If you suspect a person may be having a stroke, the "F.A.S.T." warning signs can help – as recommended by the American Stroke Association. This acronym includes signs of stroke to look out for that include:
F . Face drooping to one side that will be obvious if you ask the person to smile and it appears uneven.
. Face drooping to one side that will be obvious if you ask the person to smile and it appears uneven. A . Arm weakness or numbness that may be apparent if you ask the person to raise both arms and they can't lift one or one arm drifts downward after being raised.
. Arm weakness or numbness that may be apparent if you ask the person to raise both arms and they can't lift one or one arm drifts downward after being raised. S . Speech difficulty such as being hard to get words our or words that sound slurred.
. Speech difficulty such as being hard to get words our or words that sound slurred. T. Time to call 911 if you identify such signs, as a stroke is a medical emergency that requires immediate care.
Once in the hospital, "treatment depends on the type and severity of the stroke," says Thachil. Ischemic strokes, he explains, may be treated with clot-busting medications like tPA, or, in more severe cases, with specialized devices introduced through a catheter. "Hemorrhagic strokes require a different approach and are typically managed by neurosurgery," says Hanna.
After oxygen stabilization and treatment, blood thinning or antiplatelet medications are often prescribed to decrease the patient's risk of having another stroke. Blood pressure and cardiovascular health are also carefully monitored going forward to prevent future damage.
"Recovery approaches such as rehab, medications and/or lifestyle changes," says Thachil, "are tailored to the needs of each individual patient based on the extent of their brain injury."