Stroke (Brain Attack)

Stroke is the No. 3 cause of death in the United States and is the leading cause of serious, long-term disability. Among people over age 55, the incidence of stroke more than doubles with each additional decade (see bar graph). There are an estimated 4.4 million stroke survivors.

Each year about 500,000 Americans suffer new stroke and 100,000 suffer a recurrent stroke. About 29 percent of those who have a new stroke diet within the year and this proportion increases among those who are older. Among those who survive, 31 percent will no longer live independenntly; 20 percent will need help walking; 71 percent are no longer able to work; and 16 percent require insitutionalization. More than half of those who survive their stroke will die within 8 years.

A stroke or "brain attack" occurs because the blood flow to the brain is restricted which damages or kills (infarcts) brain cells. Depending on the severity and location of the stroke, people may have difficulty speaking, numbness on one half of the body, double vision, weakness of the face, and weakness on both sides of the body. Approximately 85% of strokes are occlusive and the remainder are hemorrhagic. Regardless of the type of stroke, the outlook will depends on the size and location

In an occlusive stroke, a blockage of a cerebral blood vessel prevents blood flow from reaching the brain. The occluding matter may form at the site of blockage or may travel from elsewhere in the body.

The most common cause of thrombotic stroke is atherosclerosis which occludes an artery and deprives an area of the brain area of oxygen. Thrombotic strokes are dynamic and may progress after the initial onset over several hours or days. They are thought to occur more commonly during sleep or shortly upon awakening.

The heart is the major source of emboli in most cases of embolic stroke. Embolic stroke is not generally preceded by any forewarning symptoms. It is classically described as a "bolt out of the blue" with the full-blown neurological deficit developing within a few minutes.

In a hemorrhagic stroke, a blood vessel ruptures causing blood to leak into brain tissues. Hemorrhagic strokes are associated with advancing age and hypertension. The mortality rate from a hemorrhagic stroke is higher (30% to 50%) than it is for an ischemic infarction (15% to 20%).

Neurological symptoms which last less than 24 hours are called transient ischemic attacks (TIAs). TIAs require immediate evaluation and intervention because half of all strokes occur within a year of the last TIA. One third of all persons with TIAs suffer a stroke within 5 years.

Diagnosis

An angiogram is the definitive method for evaluating the circulation to the brain and diagnosing cerebrovascular disease. Brain imaging studies such computerized axial tomography (CAT) scan or magnetic resonance imaging (MRI) scan are often used to confirm a diagnosis of a stroke and to determine the cause.

• Sudden, severe headache
• Unexplained dizziness, unsteadiness, or falls,
• Sudden dimness or loss of vision
• Difficulty speaking or understanding speech
• Weakness or numbness of the face, arm, or leg on one side of the body.

Treating Stroke

Until recently, prognosis following an acute stroke was grim. However, advances in treatment have resulted in more positive outcomes that have restored hope to stroke victims and their families. For those who have suffered a stroke, the aim of therapy is to prevent or reduce the amount of injury to brain tissues. Aspirin and/or anticoagulant therapy (e.g. heparin, coumadin) is initiated to prevent new clot formation. It is critical that this therapy is not given in the hemorrhagic type of stroke.

Recently, the FDA has approved tissue plasminogen activator (t-PA), a clot dissolving or thrombolytic drug for treating acute occlusive stroke. A large study found that patients who received t-PA had a 30% better chance of recovery and better survival at 3 months compared with those who didn't receive the drug. However, t-PA must be given within 3 hours to be effective and often people do not seek medical help soon enough. The drug dissolves artery-blocking clots and can rapidly restore blood flow to the brain thereby minimizing damage to brain tissue. However, this drug is not without risk-- it can cause additional bleeding and possibly death.

Recovery from stroke often requires intensive rehabilitation. People with stroke may have disabilities that include paralysis, cognitive deficits, speech problems, emotional difficulties, daily living problems, and pain. A common disability is hemiplegia- paralysis on one side of the body. A stroke in the left hemisphere will cause right-sided paralysis while a stroke in the right hemisphere causes deficits in the left side. Stroke patients often have dysphagia which causes trouble eating and swallowing. Stroke can also affect thinking, attention, judgement and memory. Stroke survivors may experience problems understanding or forming speech. A stroke may also result in emotional problems. One in three stroke victims suffer clinical depression in the year following the stroke which can hamper recovery and rehabilitation.

The level of functioning before the stroke is a significant factor in determining their rehabilitation potential. Most patients regain their maximum function by about 9 months later. Support groups can be helpful in providing an environment for problem solving, support, and acceptance.

Prevention of Stroke

The most effective way to prevent a stroke is to reduce your risk. Hypertension is one of the most prevalent and modifiable risk factors for stroke. Hypertension can increase risk six fold and therefore an elevated blood pressure-- either systolic or diastolic-- should be treated aggressively. Decreasing diastolic blood pressure by 6 mm HG reduces the risk for stroke by 42%.

Heart disease is another common cause of stroke. In particular, people with cardiac arrhythmias, are vulnerable to clots and have 6 times the risk of stroke.

High Cholesterol increases the risk for stroke because it accelerates atherosclerosis and thereby increases the chances of an occluded vessel. A study following 9,014 patients found that those who have heart disease who used provastin (a statin drug) to reduce their cholesterol levels experienced a 20% risk reduction for stroke (LIPID trial, 1995). Diabetes increases risk for stroke threefold and diabetics need to closely control their blood sugar levels to reduce risk. Lifestyle choices such as smoking and alcohol increase risk for stroke by three to four times.

Risk Factors For Stroke

• Age
• Male
• Transient Ischemic Attacks (TIAs)
• Hypertension
• Heart and arrhythmias disease
• Atrial fibrillation
• Diabetes
• High Cholesterol
• Asymptomatic carotid artery stenosis
• Smoking
• Heavy alcohol use