A stroke is an interruption of the blood supply to any part of the brain. A stroke is sometimes called a "brain attack."

Cerebrovascular disease; CVA; Cerebral infarction; Cerebral hemorrhage; Ischemic stroke; Stroke - ischemic

Every 45 seconds, someone in the United States has a stroke. A stroke can happen when:

• A blood vessel carrying blood to the brain is blocked by a blood clot. This is called an ischemic stroke.
• A blood vessel breaks open, causing blood to leak into the brain. This is a hemorrhagic stroke.

If blood flow is stopped for longer than a few seconds, the brain cannot get blood and oxygen. Brain cells can die, causing permanent damage.

ISCHEMIC STROKE

This is the most common type of stroke. Usually this type of stroke results from clogged arteries, a condition called atherosclerosis. (See stroke secondary to atherosclerosis.) Fatty deposits collect on the wall of the arteries, forming a sticky substance called plaque. Over time, the plaque builds up. Often, the plaque causes the blood to flow abnormally, which can cause the blood to clot. There are two types of clots:

• A clot that stays in place in the brain is called a cerebral thrombus.
• A clot that breaks loose and moves through the bloodstream to the brain is called a cerebral embolism.

The symptoms of stroke depend on what part of the brain is damaged. In some cases, a person may not even be aware that he or she has had a stroke.

Usually, a SUDDEN development of one or more of the following indicates a stroke:

• Weakness or paralysis of an arm, leg, side of the face, or any part of the body
• Numbness, tingling, decreased sensation
• Vision changes
• Slurred speech, inability to speak or understand speech, difficulty reading or writing
• Swallowing difficulties or drooling
• Loss of memory
• Vertigo (spinning sensation)
• Loss of balance or coordination
• Personality changes
• Mood changes (depression, apathy)
• Drowsiness, lethargy, or loss of consciousness
• Uncontrollable eye movements or eyelid drooping

If one or more of these symptoms is present for less than 24 hours, it may be a transient ischemic attack (TIA). A TIA is a temporary loss of brain function and a warning sign for a possible future stroke.

In diagnosing a stroke, knowing how the symptoms developed is important. The symptoms may be severe at the beginning of the stroke, or they may progress or fluctuate for the first day or two (stroke in evolution). Once there is no further deterioration, the stroke is considered completed.

During the exam, your doctor will look for specific neurologic, motor, and sensory deficits. These often correspond closely to the location of the injury in the brain. An examination may show changes in vision or visual fields, abnormal reflexes, abnormal eye movements, muscle weakness, decreased sensation, and other changes. A "bruit" (an abnormal sound heard with the stethoscope) may be heard over the carotid arteries of the neck. There may be signs of atrial fibrillation.

Tests are performed to determine the type, location, and cause of the stroke and to rule out other disorders that may be responsible for the symptoms. These tests include:

• Head CT or head MRI -- used to determine if the stroke was caused by bleeding (hemorrhage) or other lesions and to define the location and extent of the stroke.
• ECG (electrocardiogram) -- used to diagnose underlying heart disorders.
• Echocardiogram -- used if the cause may be an embolus (blood clot) from the heart.
• Carotid duplex (a type of ultrasound) -- used if the cause may be carotid artery stenosis (narrowing of the major blood vessels supplying blood to the brain).
• Heart monitor -- worn while in the hospital or as an outpatient to determine if a heart arrhythmia (like atrial fibrillation) may be responsible for your stroke.
• Cerebral (head) angiography -- may be done so that the doctor can identify the blood vessel responsible for the stroke. Mainly used if surgery is being considered.
• Blood work may be done to exclude immune conditions or abnormal clotting of the blood that can lead to clot formation.