A stroke may be caused by a blocked artery (ischemic stroke) or the leaking or bursting of a blood vessel (hemorrhagic stroke). Some people may experience only a temporary disruption of blood flow to the brain (transient ischemic attack, or TIA) that doesn’t cause permanent damage.
About 80 percent of strokes are ischemic strokes. Ischemic strokes occur when the arteries to your brain become narrowed or blocked, causing severely reduced blood flow (ischemia). The most common ischemic strokes include:
- Thrombotic stroke. A thrombotic stroke occurs when a blood clot (thrombus) forms in one of the arteries that supply blood to your brain. A clot may be caused by fatty deposits (plaque) that build up in arteries and cause reduced blood flow (atherosclerosis) or other artery conditions.
- Embolic stroke. An embolic stroke occurs when a blood clot or other debris forms away from your brain — commonly in your heart — and is swept through your bloodstream to lodge in narrower brain arteries. This type of blood clot is called an embolus.
Hemorrhagic stroke occurs when a blood vessel in your brain leaks or ruptures. Brain hemorrhages can result from many conditions that affect your blood vessels. These include:
- Uncontrolled high blood pressure (hypertension)
- Overtreatment with anticoagulants (blood thinners)
- Weak spots in your blood vessel walls (aneurysms)
A less common cause of hemorrhage is the rupture of an abnormal tangle of thin-walled blood vessels (arteriovenous malformation). Types of hemorrhagic stroke include:
- Intracerebral hemorrhage. In an intracerebral hemorrhage, a blood vessel in the brain bursts and spills into the surrounding brain tissue, damaging brain cells. Brain cells beyond the leak are deprived of blood and are also damaged.High blood pressure, trauma, vascular malformations, use of blood-thinning medications and other conditions may cause an intracerebral hemorrhage.
- Subarachnoid hemorrhage. In a subarachnoid hemorrhage, an artery on or near the surface of your brain bursts and spills into the space between the surface of your brain and your skull. This bleeding is often signaled by a sudden, severe headache.A subarachnoid hemorrhage is commonly caused by the bursting of a small sack-shaped or berry-shaped aneurysm. After the hemorrhage, the blood vessels in your brain may widen and narrow erratically (vasospasm), causing brain cell damage by further limiting blood flow.
Transient ischemic attack (TIA)
A transient ischemic attack (TIA) — sometimes known as a ministroke — is a temporary period of symptoms similar to those you’d have in a stroke. A temporary decrease in blood supply to part of your brain causes TIAs, which may last as little as five minutes.Like an ischemic stroke, a TIA occurs when a clot or debris blocks blood flow to part of your nervous system — but there is no permanent tissue damage and no lasting symptoms.
Seek emergency care even if your symptoms seem to clear up. Having a TIA puts you at greater risk of having a full-blown stroke, causing permanent damage later. If you’ve had a TIA, it means there’s likely a partially blocked or narrowed artery leading to your brain or a clot source in the heart.It’s not possible to tell if you’re having a stroke or a TIA based only on your symptoms. Even when symptoms last for under an hour, there is still a risk of permanent tissue damage.
Risk Factors Of Stroke
Many factors can increase your Risk Factors Of Stroke. Some factors can also increase your chances of having a heart attack. Potentially treatable Risk Factors Of Stroke include:
Lifestyle Risk Factors Of Stroke
- Being overweight or obese
- Physical inactivity
- Heavy or binge drinking
- Use of illicit drugs such as cocaine and methamphetamines
Medical Risk Factors Of Stroke
- Blood pressure readings higher than 120/80 millimeters of mercury (mm Hg)
- Cigarette smoking or exposure to secondhand smoke
- High cholesterol
- Obstructive sleep apnea
- Cardiovascular disease, including heart failure, heart defects, heart infection or abnormal heart rhythm
- Personal or family history of stroke, heart attack or transient ischemic attack.
Other factors associated with a higher risk of stroke include:
- Age —People age 55 or older have a higher Risk Factors Of Stroke than do younger people.
- Race — African-Americans have a higher Risk Factors Of Stroke of stroke than do people of other races.
- Sex — Men have a higher risk of stroke than women. Women are usually older when they have strokes, and they’re more likely to die of strokes than are men.
- Hormones — use of birth control pills or hormone therapies that include estrogen, as well as increased estrogen levels from pregnancy and childbirth.