Stroke

Introduction

Although death rates from stroke have declined over the recent years, it remains the third leading cause of death in the United States. Most stroke symptoms are not associated with pain, causing people to delay medical treatment. Signs and symptoms of stroke can range from difficulty with speech to sudden numbness or weakness in the face or limbs. Prevention is of primary importance, and proper prevention requires reduction of risk factors in persons at the highest risk.

What is it?

There are two main types of strokes:

1. An ischemic stroke occurs when there is a decrease in the amount of oxygen that is delivered to the brain by the blood vessels.

2. A hemorrhagic stroke occurs when a blood vessel wall is torn and bleeding occurs in the brain as a result of the tear in the blood vessel.

About 88% of all strokes are ischemic in nature, with hemorrhagic stroke occurring only 12% of the time. Ischemic strokes are more common because there are more causes or risk factors associated with ischemic strokes, such as high cholesterol, heart disease, other heart conditions (heart failure), and high blood pressure, as opposed to a hemorrhagic stroke, where trauma to the head or high blood pressure are the main causes or risk factors.

Transient ischemic attacks (TIAs) are a condition related to strokes. A TIA is a "mini" ischemic stroke that lasts only a few minutes. It occurs when the blood supply to the brain is temporarily interrupted. TIA symptoms, which usually occur suddenly, are similar to those of a full-blown ischemic stroke, but they don't last as long. Most symptoms of a TIA disappear within an hour, although they may persist for up to 24 hours. Symptoms of a TIA can include sudden difficulty with vision, speech, behavior, and thought.

TIAs occur before an ischemic stroke in about 60% of cases, and 35% of untreated patients will develop a stroke within 5 years of a TIA. The greatest risk for stroke is early, within the first year after the TIA, with about 20% occurring within the first month and 50% within the first year after the TIA. The more frequently TIAs occur, the higher the possibility of stroke.

What causes it?

Ischemic Strokes

There are two causes of ischemic strokes:

1. Atherosclerosis and Thrombosis: Thrombosis is the formation of a blood clot (or thrombus). Atherosclerosis (hardening of the blood vessels as a result of the build up of fatty contents and cholesterol plaques on the vessel wall) causes blood vessels to narrow and restrict blood flow, which can lead to formation of a blood clot. If a blood clot develops in a blood vessel that supplies blood to the brain, the oxygen supply to the brain can be diminished or completely blocked leading to an ischemic stroke.

2. Atrial Fibrillation and Embolism: An embolism is a dislodged blood clot that has traveled through the blood vessels and it becomes wedged in an artery. In about 15% of all strokes, the emboli are blood clots that originally formed in the heart as a result of a rhythm disorder known as atrial fibrillation -- a rapid, irregular beat in the upper chambers of the heart (the atria). Because of the irregular pumping, some blood may pool in the heart chamber and form a clot, which can then break off and travel to the brain as an emboli, causing an ischemic stroke.

Hemorrhagic Stroke

A hemorrhagic stroke occurs when there is a sudden bleed in the brain. A hemorrhagic stroke is usually the result of high blood pressure combined with arteriosclerosis (hardening of the blood vessels due to the build up of fatty contents and cholesterol plaques on the vessel wall), resulting in too much pressure on the blood vessel walls.

Hemorrhagic strokes can occur in two places:

1. A cerebral hemorrhage occurs when a faulty blood vessel in the brain bursts, flooding the nearby areas of the brain. The most common sites are the basal ganglia (an area in the brain responsible for controlling voluntary movements and establishing postures), the cerebellum (an area in the brain that provides coordination of finely executed complex movements, including speech) the thalamus (an area in the brain that is the center of pain, touch, and temperature) and the pons (an area in the brain that acts as a relay station for messages in the brain and is important centers for regulating breathing).

2. A subarachnoid hemorrhage occurs when a blood vessel in the brain bursts, causing sudden bleeding into the space between the middle lining of the brain (the arachnoid membrane) and the brain itself. A subarachnoid hemorrhage causes sudden, severe pain in the head; a person may describe it as "the worst headache I have ever had."

Who has it?

As mentioned previously, stroke is the third leading cause of death in the United States. Stroke can occur in both women and men and in all ethnic groups although certain groups are at higher risk for dying from strokes (see "What are the risk factors?"). Strokes mainly occur in adults; children are rarely afflicted.

In 2006, the American Stroke Association estimated that in the United States nearly 157,00 people die from a stroke each year, and that cumulatively 4.6 million people survived a stroke. It is estimated that 700,000 people per year have a new or recurrent stroke. One of the major impacts of stroke is the resultant disability -- up to 50% of stroke victims experience some form of physical or mental disability after their stroke.

What are the risk factors?

Risk factors are characteristics that may increase your chance for developing a condition. For ischemic and hemorrhagic stroke, risk factors include the following:

Risk factors that can't be controlled:

• Age -- The risk for stroke increases with age. This risk doubles every decade that a person is over the age of 55 years. Most stroke victims are 65 years or older.

• Gender -- Men have about a 30% higher risk for stroke than women do until the age of 55 years. After the age of 55 years, the risk is the same for men and women.

• Race -- Higher death rates from stroke occur in African Americans, Asian-Pacific Islanders, and Hispanics than in whites as a result of increased incidence of high blood pressure.

• Heredity -- The risk for stroke is greater if a parent, brother, or sister has a stroke or transient ischemic attack.

Risk factors that can be changed or that can be controlled:

• High blood pressure
• Heart disease
• TIAs
• Diabetes
• High cholesterol
• Cigarette smoking
• Alcohol
• Illicit drug use
• Lifestyle factors - inactivity, obesity, poor diet and stress
• High estrogen oral contraceptives, especially in women over 35 years who smoke and women over 40 years who have hypertension or diabetes
• Sickle cell disease

What are the symptoms?

Ischemic stroke

General symptoms of an ischemic stroke include a sudden onset of the following:

• Numbness, weakness, or inability to move (paralysis) of face, arm, or leg, usually isolated to on one side of the body

• Trouble seeing in one or both eyes (such as dimness, blurring, double vision, or loss of vision)

• Confusion, trouble speaking or understanding

• Trouble walking, dizziness, loss of balance or coordination

• Severe headache with no known cause

Symptoms can develop suddenly (within minutes). They may also progress over hours or days. Symptoms of an ischemic stroke may be so minor that they are ignored or go unnoticed, but medical attention should not be delayed.

TIA

General symptoms of TIA include sudden onset of the following:

• Numbness or weakness in the face or limbs
• Dimming or loss of vision in one eye
• Unexpected falls
• Unexplained dizziness
• Nausea
• Double vision
• Drowsiness

The difference between the symptoms of TIA and stroke is that TIA symptoms usually end after 10 to 20 minutes when blood flow resumes.

Hemorrhagic stroke

General symptoms of a hemorrhagic stroke include sudden onset of the following:

• Headache (severe and in a specific area)
• Nausea and vomiting
• Neck stiffness
• Dizziness, seizures, or changes in mental state, such as irritability, confusion, and possibly, unconsciousness

Hemorrhagic strokes often occur during the daytime and during physical activity, although this is not always true. Symptoms of a hemorrhagic stroke typically begin suddenly (within seconds) and progress over several hours.

People with very high, uncontrolled blood pressure may have one or more symptoms before they have a hemorrhagic stroke, including the following:

• Severe headache in the back of the head or top of the neck
• Dizziness or fainting
• Tingling or numbness in an arm or leg, or an inability to move an arm or leg that comes and goes

How is it treated?

Strokes can be treated and often prevented. At the moment, no treatment can cure a stroke, and most people will have some form of residual damage, which will vary from person to person. Residual damage can range from a slight limp to paralysis on one side of the body. Prevention will be the key to avoid further damage and subsequent strokes.

Prevention:

Antihypertensive agents: Reducing even mild to moderate blood pressure has been shown to lower the risk of stroke.

Cholesterol lowering agents: These agents -- "statins" like Zocor, Lipitor, Crestor, Lescol, Mevacor and Pravachol -- reduce the risk of stroke in people with existing coronary artery disease.

Treatment of Atrial Fibrillation (irregular heartbeat): The main goal of treatment for atrial fibrillation (irregular heartbeat) is to prevent blood clots from forming by first restoring and then maintaining normal heart rhythm.

Treatment for ischemic stroke:

Acute Treatment:

An acute ischemic stroke is usually treated with a thrombolytic agent. Thrombolytics, sometimes called "clot busters," dissolve the blood clot that is blocking the flow of blood through the vessel. They are considered a first-line treatment for stroke because of their high rate of effectiveness. Despite this, there is a risk of causing an intracranial hemorrhage (bleeding in the brain) with thrombolytics. Due to this increased risk for bleeding, doctors have several specific criteria that a patient must meet before thrombolytic therapy can be administered. One of the key criteria is that thrombolytics need to be administered within a certain time frame after stroke symptoms are initially recognized. So, it is really important for the patient or family members to recognize the symptoms of stroke and to get the patient to the nearest hospital within 3 hours of the onset of stroke symptoms to even qualify for thrombolytic therapy. Call 911 if you witness anyone having a stroke because time is of the essence.

Aspirin is the other important agent in the treatment of an acute ischemic stroke. Aspirin should be given more than 24 hours after the thrombolytic, but within 48 hours of symptoms. Early aspirin use has been shown to decrease long-term death and disability in stroke patients.

Chronic Treatment:

After hospitalization, most patients will need to be placed on either an antiplatelet or anticoagulant as well as other medications to control blood pressure and lower cholesterol for the rest of their lives in order to prevent another stroke.

Blood clots are also responsible for TIAs, so medications that prevent blood from clotting are also used in people who have had a TIA and are at risk for stroke.

Carotid endarterectomy is a surgical procedure used to treat and prevent an acute ischemic stroke. This procedure is an effective treatment in protecting against a first stroke in patients with severe stenosis (constriction or narrowing of a blood vessel by 70%-99%) of the main blood vessel in the brain.

Treatment for hemorrhagic stroke:

A cerebral hemorrhage is associated with extremely high death rates. It can be treated with either surgery or medical intervention and there is currently no medical consensus as to which treatment is best.

Surgical treatment involves removing the large clot from the area. The blood clot (referred to as a hematoma) size and level of consciousness of the patient are critical. Patients who are awake and have small hematomas (less than 3 centimeters diameter or less than 20cc) will usually improve without surgery, whereas comatose patients with large hematomas (greater than 6 centimeters diameter or greater than 80cc ) will usually do very poorly, regardless of management. The best candidates for surgery may be patients with moderate to large hematomas who are still awake or conscious.

Medical treatment involves monitoring blood pressure while providing adequate blood flow to the brain. If increased pressure is suspected treatment with intravenous manntiol (which reduces the pressure and excess fluids by reducing the clot) with or without furosemide (a diuretic that reduces pressure and removes excess water) may be helpful.

A subarachnoid hemorrhage can be treated with either surgery or medical treatment. Surgical treatment involves not only finding the site of the bleeding, but also stopping the bleeding in the brain. Currently, surgery in all patients in good neurological condition (meaning there are no other complications affecting the nervous system) would be the treatment of choice, if the site is surgically easy to get to and there are no other medical complications present. Medical treatment involves normalizing blood pressure, bedrest, analgesics (acetaminophen) to relieve headache and nimodipine (Nimotop) (to reduce pressure and decrease brain cell loss). Nimodipine has been shown to reduce death and hospitalizations.

Helping Yourself

For the Patient:

• A well balanced diet can help you reduce your risk for stroke. A healthful eating plan means choosing the right foods to eat and preparing foods in a healthy way. People whose diets are rich in fruits and vegetables appear to have a significantly lower risk of both ischemic and hemorrhagic stroke.

• Limit the use of alcohol to two drinks a day. Heavy drinking increases the risk of stroke and many other diseases.

• Reduce total cholesterol by eating low-fat or low-cholesterol meals.

• For patients with diabetes, maintain appropriate blood sugar levels by taking your medicine as directed by your doctor and eating a well-balanced diet approved by your doctor or nutritionist.

• Reduce mild to moderate high blood pressure by swimming, cycling, jogging, skiing, aerobic dancing, walking, or any of dozens of other activities. Studies consistently find a lower incidence of stroke in people who exercise regularly.

• Ask your doctor if you have circulation problems or an irregular heartbeat, which can increase your risk for stroke.

• If you're a woman, speak to your doctor about hormone replacement therapy and if you experience any symptoms, seek immediate medical attention.

• Seek medical attention immediately if you think you are having signs and symptoms of a stroke.

After a stroke:

As much as you may want to return to a normal life, normality may not be easy to achieve. Activities that were once done with ease will now take time to perform. At times you may become angry or sad and you may feel like no one understands what you are experiencing. This may be the time when you want to consider joining a support group. Check with your local hospital or rehab program for local support groups for you and your family members. It's important that you and your family understand the difficulties that lie ahead in living with a stroke.(To learn more about stroke recovery, visit http://www.stroke.org/.)

For the Caregiver:

The process of helping a loved one recover from a stroke can sometimes be stressful. Stroke recovery will vary from patient to patient. Recovering from a stroke usually includes treatment, natural recovery, rehabilitation, and the return to community living.

Treatment for stroke begins in the hospital. This first step includes helping the patient survive, preventing another stroke, and taking care of any other medical problems.

After the stroke, several abilities that have been lost generally start to come back. This process, known as natural recovery, happens to most people. The amount of recovery will also vary from person to person.

Rehabilitation helps the person maintain the abilities they still have and gain back the lost abilities to become more independent. It usually begins while the patient is still in the hospital. For many patients, it continues afterward. The patient, family, and hospital staff will make decisions about rehabilitation before discharge.

The last stage in stroke recovery begins with the person's return to community living after hospitalization or rehabilitation. This stage can last for a lifetime as the stroke survivor and the family learn to live with the effects of the stroke. This may include doing common tasks in new ways or making up for damage to or limits of one part of the body by greater activity of another. For example, a stroke survivor can wear shoes with velcro closures instead of laces or may learn to write with the opposite hand.

What is on the horizon?

New therapy for prevention of TIAs and stroke includes a number of new and emerging interventions. Different strategies that restore blood flow to the brain, including longer-acting thrombolytics, anti-platelets and laser-guided clot removal are being researched. Therapies that help reverse the effects of an acute stroke are also being investigated.

References

Pulsinelli WA. Neurology. In Cecil Textbook of Medicine. 20th ed. W.B. Saunders Company eds. 1996: 2057-2080.

Fagan SC, Hess DC. Stroke. In Diprio JT, Talbert RL eds. Pharmacotherapy A Pathophysiologic Approach. 6th ed. McGraw-Hill 2005: 415-427.

Easton JD, Hauser SL, Martin JB. Cerebrovascular diseases. In Fanci AS, Braunwald E, Isselbacher KJ, Wilson JD, Martin JB, eds. Harrison's Principles of Internal Medicine. 14th ed. New York, NY: McGraw-Hill; 1998: chapter 366.

Frishman WH, Klein MD, and others. Antiplatelet and Other Antithrombotic Drugs. In: Frishman WH, Sonnenblack EH, eds. Cardiovascular Pharmacotherapeutics. U.S. McGraw-Hill. 1996: 323-379.

Vornov JJ. Stroke. In Enna SJ, Coyle JT, eds. Pharmacological Management of Neurological and Psychiatric Disorders. U.S. McGraw-Hill. 1998: 505-524.

Stroke. American Stroke Association. Available at: http://www.strokeassociation.org. Accessed December 2007.

Stroke. National Stroke Association. Available at: http://www.stroke.org/. Accessed December 2007.

Stroke Health Condition Last Updated: December 2007

Note: The above information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist, or other healthcare professional. It is not intended to diagnose a health condition, but it can be used as a guide to help you decide if you should seek professional treatment or to help you learn more about your condition once it has been diagnosed.

Back