Strokes are life-threatening emergencies. They happen when the blood flow to the brain is disrupted, and your brain cells can’t get the oxygen and nutrients they need.
Knowing the difference between types of strokes helps with preventing them and with getting the right treatment. For example, clot-busting drugs can be lifesaving in ischemic strokes but could make a hemorrhagic stroke worse.
The three main types of strokes are called ischemic, hemorrhagic and transient ischemic attack (TIA).
An ischemic stroke is the most common type of stroke. About 87% of all strokes are this type.
An ischemic stroke occurs when an artery that supplies blood to the brain becomes blocked. That usually happens due to a blood clot that forms in the blood vessels in or leading to the brain. A buildup of fatty deposits in the artery walls (atherosclerosis) may make the arteries more narrow and increase the risk of clots forming in them.
With an ischemic stroke, brain cells in the area begin to die. You start to lose the functions controlled by that part of the brain. How severe the effects are depends on where in the brain the stroke is located and how much of the brain tissue is blocked.
There are two main subtypes of ischemic stroke.
These strokes happen when a clot forms directly in one of the brain’s arteries. They are usually linked to atherosclerosis.
You’re at higher risk for a thrombotic stroke if you have high cholesterol, diabetes or a family history of heart disease. Smoking, eating a lot of unhealthy foods and being physically inactive increase your risk.
These strokes happen when a clot forms somewhere else in the body, often the heart, and travels to the brain. The clot becomes lodged in a smaller artery and blocks blood flow.
You’re at higher risk for an embolic stroke if you have a history of heart attack or heart failure or you have certain heart conditions, including atrial fibrillation, which causes irregular heartbeats that can lead to clots.
A hemorrhagic stroke happens when a blood vessel in the brain ruptures and causes bleeding in or near the brain. Hemorrhagic strokes are less common than ischemic strokes, but they are usually more severe and can be life-threatening.
They happen when high blood pressure or weak blood vessel walls cause vessels to burst. Abnormalities in the blood vessels such as aneurysms and arteriovenous malformations (AVMs) and liver disease can lead to this bleeding.
With a hemorrhagic stroke, the bleeding causes swelling and pressure that damages brain cells. The extent of the brain damage depends on how quickly the bleeding is stopped and the pressure on the brain eases up.
There are two main subtypes of hemorrhagic stroke.
These strokes happen when you have bleeding directly into the brain tissue.
They are often caused by high blood pressure, which stresses and weakens small arteries in the brain. Other causes include trauma, blood-thinning medications (anticoagulants) and brain tumors.
These strokes happen when you have bleeding in the space between the brain and the surrounding membrane (the subarachnoid space).
They are often caused by ruptured aneurysms or head injuries. With one, you may have a sudden, severe headache that feels like the worst headache of your life.
A transient ischemic attack (TIA), often called a mini stroke, happens when the blood flow to the brain is blocked temporarily. TIAs have similar symptoms to other strokes but the symptoms go away in minutes or hours.
TIAs happen when a clot blocks an artery, but your body dissolves it and your blood flow returns to normal. The same risk factors that cause ischemic strokes, like high blood pressure, high cholesterol and atrial fibrillation, also raise your risk of a TIA.
A TIA is a major warning sign that you might have a stroke in the future. About one-third of people who have a TIA have a more severe stroke within a year if they don’t manage their risk factors. If you have a TIA, you need an immediate medical evaluation to identify and reduce your risk of another stroke.
Time is critical with any type of stroke. Recognizing symptoms and acting quickly can make a difference.
The letters FAST can help you remember the main stroke symptoms:
You may also notice other symptoms based on the type of stroke:
Describing stroke symptoms you notice in yourself or someone else can help health care providers figure out which type of stroke is happening so they can provide the right treatment.
At Banner Health, we are dedicated to stroke care and education. We can help you understand your stroke risk, manage health conditions that are linked with stroke and support you in preventing them. Our team of specialists is here to guide you every step of the way.
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