Stroke is the fourth leading cause of death and the leading cause of disability in the United States. When a stroke occurs, a blood vessel in the brain becomes blocked or bursts, sometimes causing permanent brain injury or even death. However, prompt treatment and follow-up care may protect brain cells and help patients lead healthy, productive lives.
There are two main types of strokes:
- Ischemic Stroke — This type of stroke accounts for about 80 to 85 percent of all strokes in the United States. With ischemic stroke, the blood supply to a part of the brain becomes blocked. This prevents oxygen and nutrients from reaching brain cells. Within a few minutes, these cells may begin to die.
The underlying cause for this type of obstruction is usually atherosclerosis, a condition in which plaque or fatty deposits within the wall of the arteries in the brain and neck can lead to obstruction or narrowing. These fatty deposits can cause cerebral thrombosis or cerebral embolism. With a cerebral thrombosis, a blood clot forms within the blood vessel. Cerebral embolisms are clots that can form at another location in the circulatory system, break loose from an artery wall or from the inside lining of the heart, travel through the brain's blood vessels and can lodge in an artery in the brain.
- Hermorrhagic Stroke — With hemorrhagic stroke a blood vessel within the brain leaks or ruptures and bleeds into the surrounding brain tissue. This is called an intracerebral hemorrhage. The blood can accumulate and exert pressure on the surrounding tissue. High blood pressure is a common cause of intracerebral hemorrhage. In a subarachnoid hemorrhage, blood leaks under the lining of the brain. This is often caused by a small bubble on an artery known as an aneurysm.
Risk Factors for Stroke
Risk factors for stroke that cannot be changed:
- Family History — The risk of having a stroke is higher for people whose parents or siblings have had a stroke.
- Age — Stroke risk increases with age — doubling every 10 years after age 55.
- Gender — Before age 55, men are more likely than women to have strokes. After 55, the risk is the same for men and women. However, women are more likely than men to die of stroke.
- History of Prior Stroke, TIA or Heart Attack — A person who has had a stroke in the past is at much greater risk for having another one. Risk of stroke after a TIA is greatest within the first 48 to 72 hours. Therefore, you should seek immediate medical attention for all acute neurologic changes, even if they have resolved.
- Race — African Americans have higher incidence of stroke and a higher risk of death from a stroke than Caucasians do. Asian Americans have higher incidence of hemorrhagic stroke than other ethnic groups.
Risk factors for stroke that are modifiable:
- High Blood Pressure — This is probably the most important modifiable risk factor for stroke. Controlling high blood pressure will greatly reduce your risk of stroke and heart attack.
- Cardiovascular Disease — Congestive heart failure, a previous heart attack, a diseased aortic valve and atrial fibrillation can all raise the risk of stroke.
- Cigarette Smoking — The risk of stroke is two to three times greater for smokers versus nonsmokers. The use of oral contraceptives with cigarette smoking greatly increases the risk of stroke.
- Carotid Artery Disease — Fatty deposits from atherosclerosis may cause significant narrowing in the carotid arteries. This can limit blood flow to the brain as well as acts as a potential source for cerebral emboli.
- Diabetes — Diabetes doubles stroke risk. Many people with diabetes also have high blood pressure, obesity and high cholesterol, which increase their stroke risk even further.
- Undesirable Blood Cholesterol Levels — High blood levels of low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol increase stroke risk.
- Obesity — Excess weight can double the risk of an ischemic stroke.
- Lack of Exercise and Physical Activity — Both increase the risk of high blood pressure and therefore the risk for stroke. Taking the stairs, going on a brisk walk, doing some kind of activity for at least 30 minutes every day will help decrease your stroke risk.
- Use of Birth Control and Hormone Therapy — Women who use birth control pills, especially if they smoke and are over age 35, have a higher risk of stroke. There is also a higher risk of stroke among women using hormone therapy for menopause.
If you are experiencing any symptoms of stroke, you should go to a doctor or hospital right away, preferably by dialing 911.
Common symptoms of stroke include:
- Sudden paralysis of a leg, arm or one side of the face
- Sudden trouble speaking or understanding speech
- Sudden vision problems, such as blurred or double vision
- Sudden loss of coordination or problems with balance
- A severe, sudden headache without apparent cause
- Sudden numbness, weakness or dizziness
Transient Ischemic Attack (TIA)
Transient ischemic attacks are sometimes called "mini-strokes." Although strokes typically occur without warning, some people may feel a temporary numbness, weakness or tingling in one arm or leg, or problems with speech, vision or balance before the actual onset of the stroke. This occurs because the blood supply to the brain is temporarily reduced, called a transient ischemic attack (TIA).
The neurovascular team at UCSF Medical Center, along with your primary care doctor, will design a treatment plan tailored to your medical condition, state of health and individual needs. You may need more than one kind of treatment, and you may require several visits to UCSF. You may be referred to additional doctors or other medical professionals.
It is critical to come to the hospital immediately if you experience a stroke because treatments might reduce or completely reverse the brain injury from stroke. These treatments must be given within the first few hours of stroke symptoms, so call 911 to get transportation to the Emergency Room quickly. These treatments include administration of a t-PA — a drug that opens blocked blood vessels — or devices to remove the clot from the brain using a catheter.
The next step in treating a stroke is to carefully control and monitor your blood pressure. Once your blood pressure is under control, we focus on cholesterol, smoking cessation, control of diabetes and analysis of any heart conditions you may have.
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Reviewed by health care specialists at UCSF Medical Center.