Stroke is the third-leading cause of death in the United States and the leading cause of serious, long-term disability. A stroke occurs when a blood vessel (artery) that supplies blood to the brain leaks, bursts or is blocked by a blood clot. Within an hour, the nerve cells in that area of the brain become damaged and die. As a result, the part of the body controlled by the damaged area of the brain cannot work properly.
At Cedars-Sinai, the Stroke Center is dedicated to preventing, diagnosing and treating strokes, applying the latest technology and medications while treating the stroke patient's entire needs. Care is coordinated from the first point of contact with the patient, whether through the Emergency Department, the Stroke Center's inpatient or outpatient services or Medical Rehabilitation.
Symptoms of a Stroke
A person having symptoms of a stroke needs immediate emergency care, just as if he or she were having a heart attack. The sooner medical treatment begins, the fewer brain cells that are damaged.
The effects of a stroke may range from mild to severe and may be temporary or permanent. A stroke can affect vision, speech, behavior, the ability to think and the ability to move parts of the body. Sometimes it can cause a coma or death. The effects of a stroke depend on the specific brain cells that are damaged, how much of the brain is affected and how fast blood flow is restored to the affected area.
One or more mini-strokes (transient ischemic attacks or TIAs) may occur before a person has a full-blown stroke. Symptoms for both are similar. However, unlike stroke symptoms, TIA symptoms disappear within minutes (usually 10 to 20) up to 24 hours. A TIA is a warning signal that a stroke may soon occur, and the condition needs to be treated as an emergency.
There are two major types of strokes. Ischemic stroke is caused by a blocked or narrowed artery. Hemorrhagic stroke is caused by sudden bleeding from an artery.
General symptoms of a stroke include sudden onset of:
- Numbness, weakness or inability to move (paralysis) of the face, arm or leg, especially on one side of the body
- Trouble seeing in one or both eyes, such as dimness, blurring, double vision or loss of vision
- Confusion or trouble speaking
- Trouble walking, dizziness or loss of balance or coordination
- Severe headache with no known cause
Causes and Risk Factors for Strokes
Ischemic stroke occurs when blood flow through a blood vessel (artery) that supplies blood to the brain is blocked.
Blockage may develop from a blood clot in an artery leading to the brain (thrombus) or one formed in another part of the body, usually the heart (embolus). The clot travels with the blood until it blocks an artery in the brain.
These blood clots can be caused by an irregular heart beat, heart valve problems, infection of the heart muscle, hardening of the arteries, blood-clotting disorders, inflammation of the blood vessels or heart attack. They may also be caused by a clot that breaks away from a ruptured cerebral aneurysm or a bleeding arteriovenous malformation.
A less common cause of ischemic stroke occurs when blood pressure becomes too low (hypotension), reducing blood flow to the brain. This usually occurs with narrowed or diseased arteries. Low blood pressure can result from a heart attack, large loss of blood or severe infection. Each of these conditions affects the flow of blood through the heart and blood vessels and increases the risk of stroke. Additionally, surgery to correct narrowed or blocked arteries in the neck may sometimes cause a stroke.
Hemorrhagic stroke is caused by sudden bleeding from a blood vessel inside the brain (cerebral hemorrhage) or in the spaces around the brain (subarachnoid hemorrhage). Sudden bleeding may result from the bursting of a blood vessel that has stretched and thinned (aneurysm). The most common cause of bleeding inside the brain is high blood pressure.
Uncommon causes of hemorrhagic stroke include inflamed blood vessels, which may develop from syphilis or tuberculosis, blood-clotting disorders, head or neck injuries, radiation treatment for cancer or cerebral amyloid angiopathy (a condition in which a protein substance builds up and weakens the blood vessels in the brain, causing bleeding and a stroke).
Diagnosing a Stroke
Diagnosis of a stroke is based on the patient's medical history and a physical exam. A variety of diagnostic tests are available through the Stroke Center at Cedars-Sinai. If stroke is suspected, the doctor will order magnetic resonance imaging (MRI) or a computed tomography (CT) scan to determine whether the stroke was caused by a clot or from bleeding inside the brain. Additional tests may be done depending on the scan results.
If disease or narrowing of one of the large arteries in the neck (carotid arteries) is suspected, the following tests may be done:
- Ultrasound of the carotid artery
- Magnetic resonance angiography (MRA) scan to show the flow of blood through the blood vessels
- Carotid arteriography (injecting radioactive material into the blood stream) to show specific arteries
- If evidence shows that the stroke is caused by a clot that formed in the heart, the doctor may order a chest X-ray, ECG or EKG, echocardiograph or other heart imaging test
- Other laboratory tests may be done to see if other conditions are present, check the person's overall health and see if the patient's blood clots too easily
Treating a Stroke
People who have symptoms of a stroke need to seek emergency medical care. Prompt medical attention may prevent life-threatening complications and more widespread brain damage and is critical for the best recovery. If emergency treatment is sought within the first one to two hours after symptoms begin, some people with a stroke caused by a blood clot may be able to receive a medication to dissolve the clot, helping to increase the chance of a full recovery.
The goals of treatment are to prevent life-threatening complications that may occur soon after stroke symptoms develop, prevent future strokes, reduce disability, prevent long-term complications and help the patient get back as much normal functioning as possible through rehabilitation.
Treatment may include medication to dissolve a blood clot (tPA) or clot removal using the Penumbra Stroke System or surgery. The type of treatment is based on the type of stroke and the seriousness of the symptoms.