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. To learn more about stroke prevention, click here.
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.
Risk Factors for Stroke
| Controllable |
Uncontrollable |
| High blood pressure |
Family History |
Atrial Fibrillation
(irregular heart beat) |
African American, Hispanic,
or Asian |
| High Cholesterol |
Age |
Diabetes
|
Gender |
| Tobacco Use/Smoking |
History of Previous strokes or blocked
arteries leading to the brain |
| Alcohol Use |
|
| Overweight |
|