Understanding the 2 Main Types of Stroke: What Causes Them and How They’re Treated

How the stroke occurs will affect how doctors treat it.

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If you suspect someone could be having a stroke, your main concern is making sure they get help and end up safe, supported, and healthy. Knowing what specific kind of stroke they’re having may not be on your mind; however, the type of stroke matters big time to the paramedics who arrive on the scene and to doctors at the hospital who decide on a course of treatment. That information will affect everything they do to support the patient.

“A stroke is an injury to the brain,” says Carolyn Brockington, MD, neurologist at Mount Sinai Hospital. “The injury is caused by an interruption of blood flow suddenly.”

Without blood flow, the brain lacks the oxygen it needs to function and live, and brain cells become damaged or die off. This results in permanent injury to the brain that may affect personality, communication, or coordination. Learn more about what having a stroke does to your brain.

There are two main types of stroke: ischemic strokes and hemorrhagic strokes.

What Is an Ischemic Stroke?

In the United States, the majority of strokes—over 80 percent— are ischemic strokes. “Ischemia means reduction in blood flow,” says Dr. Brockington. This could be caused by a blood clot or some other blockage in the artery.

Often, these obstructions in the arteries are caused by a hardening of the arteries known as atherosclerosis, according to the American Stroke Association. This begins when fatty deposits and cholesterol build up on the inner lining of the artery, which hardens and becomes plaque over time.

If the plaque from atherosclerosis ruptures, it can form blood clots that travel through the artery. If the artery leads to the heart, it can cause a heart attack; if it leads to the brain, it can cause a stroke.

What Is a Hemorrhagic Stroke?

The less common type of stroke is hemorrhagic stroke, which means there is bleeding in the brain. This type of stroke occurs when a weak blood vessel ruptures and blood begins to pool in the brain. The accumulating blood puts pressure on the nearby brain tissue.

This rupture can occur if a blood vessels “balloons” and fills up with blood (an aneurysm) or if the blood vessels are formed abnormally (an arteriovenous malformation). It’s possible to treat these conditions before the vessel ruptures and the hemorrhagic stroke occurs.

How Does the Type of Stroke Affect Treatment?

Both stroke types have present similar symptoms of a stroke, and both types require immediate attention. Find out here why calling 911 is so critical for stroke treatment.

Despite the similarities in stroke symptoms, treatment for the two types of stroke is very different. One of the first-line treatments for ischemic stroke—but NOT hemorrhagic stroke—is tPA, which stands for “tissue plasminogen activator.” A tPA is a thrombolytic drug—throm meaning “clot” and lytic meaning “dissolve.”

“If we think that ischemic strokes are from not enough blood flow getting to the brain, we know that tPA is a very strong blood thinner that improves blood flow to the brain,” says Dr. Brockington.

However, if you’re having a hemorrhagic stroke, increasing blood flow with a blood thinner could make your condition worse. Doctors will also look at your medical history for previous bleeding, and will find out if you are on blood thinners already for another condition, such as deep vein thrombosis or atrial fibrillation.

“Since we’re not going to give a blood thinner when somebody’s bleeding in the brain [from a hemorrhagic stroke], really what we have to do is support them through the injury,” says Dr. Brockington. The goal is to limit the amount of swelling in the brain, which reduces the amount of injury to the brain cells.

To treat a hemorrhagic stroke, doctors may use medications to control blood pressure. If the patient is already on blood thinners, doctors may provide a transfusion of blood clotting agents to halt the bleeding, according to UpToDate from Wolters Kluwer.

“Time Is Brain”

Regardless of the type of stroke, fast treatment is crucial. “In stroke treatment, we say ‘time is brain,’” says Dr. Brockington. “Every moment that goes by, there are a million brain cells that die.” The faster you can begin medical treatment, the fewer cells will be damaged, and the less severe your injury will be.

Find out how to use the acronym F-A-S-T to recognize stroke to get treatment sooner.