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Three Types of Strokes

There are three basic types of strokes: ischemic, hemorrhagic, or a transient ischemic attack (TIA). Each can have different warning signs and symptoms, occur in different areas of the brain, and can result in differing outcomes.

Ischemic Stroke

About 80 percent of strokes are ischemic. An ischemic stroke is most frequently caused by a blood clot that lodges in an artery and blocks the flow of blood to a part of the brain. High blood pressure is the most important risk factor for ischemic stroke.

Ischemic strokes are typically preceded by symptoms or warning signs that may include loss of strength or sensation on one side of the body, problems with speech and language or changes in vision or balance.  They usually occur at night or first thing in the morning. Symptoms develop over a few minutes or worsen over hours. Often a TIA (transient ischemic attack) [see below] or “mini-stroke” may offer some warning of a major ischemic stroke.

There are three types of ISCHEMIC strokes:

  • Thrombotic strokes are caused by a blood clot (thrombus) in an artery going to the brain.
  • Embolic strokes occur when a clot that’s formed elsewhere (usually in the heart or neck arteries) travels in the blood stream and clogs a blood vessel in or leading to the brain.
  • Systemic hypoperfusion (low blood flow) is caused by circulatory failure of the heart.

Hemorrhagic Stroke

A hemorrhagic stroke occurs when a blood vessel ruptures within the brain. About 15 to 20 percent of strokes are hemorrhagic. There are two kinds of stroke due to ruptured blood vessels:  subarachnoid hemorrhage due to ruptured aneurysms and intracerebral hemorrhage due to ruptured blood vessels.   In both types of hemorrhagic stroke, blood flow is disrupted to part of the brain.

  • Subarachnoid hemorrhage most commonly occurs when an aneurysm ruptures and bleeds into the space between the brain and the skull. Most aneurysms are congenital and rupture due to high blood pressure.
  • Intracerebral hemorrhage occurs when a blood vessel bleeds into the tissue deep within the brain.  The main causes are chronically high blood pressure and aging blood vessels. Arteriovenous Malformations (AVMs) are also congenital malformations of blood vessels in the brain which can rupture into brain tissue as they get larger.

Victims of hemorrhagic strokes are often younger and the fatality rate is higher than for ischemic stroke.  Overall prognosis is also poorer for those who have hemorrhagic strokes. The symptoms of a hemorrhagic stroke usually appear suddenly and often include:

  • very severe headache
  • nausea and vomiting.
  • partial or total loss of consciousness

Transient Ischemic Strokes (TIA)

About 10 percent of strokes follow incidents called transient ischemic attacks, or TIAs. A TIA is a “mini-stroke” that occurs when a blood clot blocks an artery for a short time. TIAs may occur days, weeks or months before the onset of a stroke. The symptoms of a TIA are like the warning signs of a stroke, but they usually last only a few minutes. TIAs are strong predictors of stroke risk. Don’t ignore them. Call 9-1-1 or seek emergency medical attention immediately.

Self Assessment

Ask yourself these questions to find out if you may be at risk for stroke.

Controllable Risk Factors

Yes No
1. Is your blood pressure over 140/90?
2. Do you have a total cholesterol over 200?
3. Is your LDL (bad cholesterol) value over 130?
4. Are you a smoker or live with someone who smokes?
5. Do you exercise less than 3 days a week, less than 30 minutes each time?
6. Is you BMI out of range for your age?
7. Do you have diabetes?
8. Do you drink more than two glasses of wine/beer/liquor per day?
9. Do you drink more than two glasses of wine/beer/liquor per day?

I have _______ controllable risk factors.

Uncontrollable Risk Factors

Yes No
1. Are you over 55 years of age?
2. Are you a male?
3. Are you an African American or do you have a history of stroke in your family?
4. Have you suffered a heart attack or stroke previously?

I have _______ uncontrollable risk factors.

Answering YES to any of these questions can increase your risk of stroke. Contact your physician if you are not being treated for any of the above controllable risk factors. If you have questions about any of the tests, or would like more information about stroke, please call (863)676-6386.