Stroke

A stroke occurs when blood flow to the brain is interrupted. If the brain lacks sufficient blood for a long enough period of time, brain damage or death can result.

There are two major types of stroke:

Ischemic stroke, in which an artery becomes blocked; and
Hemorrhagic, or bleeding, stroke.

Ischemic stroke is the most common type. Blockages can occur if major arteries in the neck or the arteries in the brain become narrowed by atherosclerosis. Usually, a piece of plaque or a blood clot that lodges in the narrowed artery causes the blockage. Sometimes the arteries themselves block blood flow if enough plaque builds up in the artery walls. Approximately 10 to 15 percent of strokes are hemorrhagic. In hemorrhagic stroke, a blood vessel inside the brain leaks or bursts. Hemorrhagic strokes are more deadly than ischemic strokes.

WHAT ARE THE SYMPTOMS?

Many patients experience a warning sign of a stroke called a transient ischemic attack (TIA), or mini-stroke. The symptoms of TIA are:

Partial loss of vision in one eye;
Weakness, tingling, or numbness in one arm and/or leg;
Temporary loss of control of movement in one arm and/or leg;
Inability to pronounce words or speak clearly; and
Unsteadiness, vertigo, double vision, or drop attacks.

TIA symptoms clear up without treatment but are potentially serious and should be promptly reported to a physician. The above symptoms indicate a stroke if they last longer than a few hours.

Most stroke-related brain damage occurs within a few hours of the onset of symptoms. Patients who experience any of the following symptoms should seek help immediately:

Difficulty swallowing;
Memory loss;
Vertigo;
Loss of balance;
Personality or mood changes;
Drowsiness or loss of consciousness; or
Uncontrollable eye movements or eye drooping.

CAUSES AND RISK FACTORS

Atherosclerosis commonly causes ischemic strokes.

Transient ischemic attack (TIA), or mini-stroke, is an important stroke risk factor.

Causes of hemorrhagic stroke include:

High blood pressure;
Aneurysms;
Arteriovenous malformations;
Brain tumors;
Coagulopathy;
Anticoagulant medications; and
Cocaine use.

Factors that increase the risk of strokes include:

Advanced age;
Male gender;
Pregnancy;
African American race;
Family history of stroke;
Prior heart attack or stroke;
Smoking;
Artery disease;
Diabetes mellitus;
Heart disease;
High cholesterol;
Alcohol or drug abuse; and
Obesity and lack of exercise.

DIAGNOSIS

To diagnose stroke, the physician will obtain a detailed description of the patient's symptoms and perform physical and neurological examinations.

Tests that the physician may order include:

Blood tests;
Computed tomography (CT) scan;
Magnetic resonance imaging (MRI);
Angiography;
Transcranial Doppler ultrasound;
Electroencephalogram (EEG); and
Evoked response test.

TREATMENT APPROACH

Ischemic stroke and hemorrhagic stroke are treated differently. Generally, physicians treat an ischemic stroke by removing the blockage that is preventing blood flow in the brain. The physician administers clot-dissolving drugs through the bloodstream to remove the blockage.

Endovascular treatments that use tiny devices to retrieve clots in the brain are being studied for ischemic stroke.

Several treatments may be used to prevent ischemic stroke, including:

Lifestyle changes;
Anticoagulant or antiplatelet medications;
Angiotensin-converting enzyme (ACE) inhibitors;
Carotid endarterectomy; and
Carotid stenting.

To treat hemorrhagic stroke, physicians create an obstruction in the damaged blood vessel to stop bleeding using surgery or minimally invasive treatments. LIFESTYLE

Lifestyle factors can contribute to the development of a stroke. Behavior modifications that can decrease stroke risk include:

Quitting smoking;
Losing weight;
Exercising regularly;
Controlling high blood pressure; and
Reducing alcohol intake.

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