Stroke
(Cerebrovascular Accident; CVA; Cerebral Infarct; Brain Attack)
by Debra Wood, RN
En Español (Spanish Version)
More InDepth Information on This Condition
Definition
Stroke is a brain injury. It occurs when the brain's blood supply is interrupted. Without oxygen and nutrients from blood, brain tissue dies quickly (less than 10 minutes). This causes a sudden function loss.
Causes
A stroke occurs when blood flow to the brain is blocked (called ischemic stroke). This is caused by one of the following:
Sudden decreased blood flow
Damage to a blood vessel supplying blood to the brain can occur suddenly from either: Injury
A clot that forms and breaks off from another part of the body (such as the heart or neck) There are certain conditions which predispose people to form blood clots, such as:
Cancer Pregnancy Atrial fibrillation
Certain autoimmune diseases Local blood clot
A build-up of fatty substances ( atherosclerotic plaque) along the inner lining of the artery causes: Narrowing of artery
Reduced elasticity Local inflammation
Decreased blood flow in the artery Clot in an artery supplying the brain
Inflammatory conditions in the blood vessels (vasculitis)
A stroke may also occur if a blood vessel breaks and bleeds into or around the brain. This is called hemorrhagic stroke.
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Risk Factors
These risk factors increase your chance of developing a stroke. Tell your doctor if you have any of these risk factors.
Risk factors you can affect:
High blood pressure (the number one risk factor for ischemic stroke) High blood homocysteine level
Drug abuse (heroin, cocaine, amphetamines)
Narrowing of arteries supplying the brain due to atherosclerosis
High cholesterol levels, particularly low-density lipoprotein (LDL) cholesterol Smoking
Diabetes mellitus
Atrial fibrillation (abnormality of heart rhythm)
Use of birth control pills if you are over 35 years old and smoke Long-term use of hormone replacement therapy*²
Risk factors you cannot affect:
Prior stroke or pre-existing cardiovascular disease such as heart attack Prior transient ischemic attack (TIA)
Some people experience a "warning stroke" or TIA. This is a temporary interruption of the brain's blood supply (mini-stroke). These are stroke symptoms that resolve completely within minutes. There may be a very high risk of having a full-blown stroke in the near future.
Age: 60 or older
Family members who have had a stroke Gender: males are at greater risk than females Race: Black, Asian, Hispanic
Blood disorders which increase clotting in sickle cell disease and polycythemia Valvular heart disease such as mitral stenosis
Symptoms
Symptoms occur suddenly. They differ depending on the part of the brain affected. Multiple symptoms arise at the same time. Call emergency help right away. Brain tissue dies quickly when deprived of oxygen.
Symptoms:
Weakness or numbness on one side of the body, including the face Seizures
Confusion
Nausea and vomiting of sudden onset Blurry, dimming, double vision, or no vision
Difficulty swallowing, talking, or comprehending others Dizziness, falling, or loss of balance
Severe or unusual headache
Diagnosis
Having a stroke is an emergency situation. Diagnosis includes: Neurological exams
Electrocardiogram (ECG, EKG) —a test that records the heart's activity by measuring electrical currents through the heart muscle
Brain and blood vessel imaging by:
CT scan —a type of x-ray that uses a computer to make pictures of the brain This test helps doctors identify hemorrhagic versus ischemic stroke. MRI scan —a test that uses magnetic waves to make pictures of the brain Ultrasonography—a test that uses sound waves to examine the brain
Blood tests especially homocysteine, prothrombin time, and other coagulation tests Some tests may include:
Arteriography (angiography)—a catheter is placed in a blood vessel in the groin and threaded up to the brain; to show arteries in the brain
Magnetic resonance angiography (MRA)—shows brain blood vessels by mapping blood flow
CT angiogram (CTA)—this test uses a CT scanner and can give images of the blood vessels inside the brain, after a dye is injected into the veins
Functional MRI—shows brain activity by picking up signals from oxygenated blood
Doppler ultrasound—shows narrowing of the arteries (carotid and vertebral) supplying the brain; evaluates flow of blood in brain
Echocardiography—a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart; to show if the clot comes from one of the heart's chambers
Treatment
Immediate treatment is needed to:
Dissolve a clot causing an ischemic stroke Stop the bleeding during a hemorrhagic stroke Other treatment aims to:
Reduce the chance of later strokes Improve functioning
Overcome disabilities
Medications
Clot-dissolving drugs
Given shortly after the start of symptoms—typically given within 3 hours by IV, or intraarterially (IA) within 6 hours
Used in carefully selected patients Blood-thinning drugs (anticoagulants)
Heparin given by vein
Oral medication ( warfarin) given if long-term treatment with blood-thinner is expected Lovenox or other related medications, given subcutaneously (under skin)
.
Antiplatelet drugs Aspirin
Clopidogrel (Plavix), dipyridamole (Persantine), and ticlopidine (Ticlid) Other drugs are used to:
Control blood pressure (labetalol, the first-line drug, or sodium nitroprusside) Reduce chance of additional clot formation (aspirin or similar medications) Reduce brain swelling
Correct irregular heart rhythm (eg, atrial fibrillation) Other interventions during an acute stroke:
Adequate oxygen
Precautions to prevent choking Frequent neurological examinations
Surgery
Surgery may be performed following a stroke or TIA to prevent a recurrence. Surgical techniques:
Carotid endarterectomy—fatty deposits are removed from a carotid artery (major arteries in the neck that lead to the brain)
Carotid angioplasty and stenting—less invasive procedure than carotid endarterectomy; the carotid artery is widened and a mesh tube is placed into the artery to keep it open
Extracranial/intracranial bypass—blood supply is rerouted around a blocked artery using a healthy scalp artery
Craniotomy—done with a hemorrhagic stroke, to relieve pressure build-up in the brain caused by swelling A study was done to compare endarterectomy to stenting. Even though endarterectomy is more invasive it led to fewer deaths. It also had fewer repeat strokes than stenting within the first six months. *¹
Rehabilitation
Physical therapy—to regain as much movement as possible Occupational therapy—assist in every day tasks and self care Speech therapy—to improve swallowing and speech challenges
To help reduce your chance of getting a stroke, take the following steps: Exercise regularly.
Eat more fruits and vegetables. Limit dietary salt and fat. Stop smoking.
Drink alcohol only in moderation (1-2 drinks per day). Maintain a healthy weight.
Frequently check blood pressure. Follow your doctor's recommendations for keeping it in a safe range. Take a low dose of aspirin (75 milligrams per day) if your doctor says it is safe.
Keep chronic medical conditions under control. This includes high cholesterol and diabetes. Seek medical care if you have symptoms of a stroke, even if symptoms stop.
Stop the use of recreational drugs (cocaine, heroin, marijuana, amphetamines).
RESOURCES:
American Heart Association http://www.americanheart.org/ National Stroke Association http://www.stroke.org/
CANADIAN RESOURCES:
Heart and Stroke Foundation of Canada http://ww2.heartandstroke.ca/
Prevent Stroke
http://www.preventstroke.ca/
REFERENCES:
Adams H, Adams R, Del Zoppo G, Goldstein LB. Guidelines for the early management of patients with ischemic stroke: 2005 guidelines update: a scientific statement from the Stroke Council of the American Heart
Association/American Stroke Association. Stroke . 2005;36:916-923.
Duncan PW, Zorowitz R, Bates B, et al; Stroke Council of the American Heart Association/American Stroke Association. Management of adult stroke rehabilitation care: a clinical practice guideline. Stroke .
2005;36:100-143.
Grau AJ, Barth C, Geletneky B, et al. Association between recent sports activity, sports activity in young adulthood, and stroke. Stroke. 2009;40:426-431. Epub 2008 Dec 24.
Rowland LP, Merritt HH. Merritt's Neurology . 11th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005. Sacco RL, Adams R, Albers G, et al. Guidelines for prevention of stroke in patients with ischemic stroke or transient ischemic attack: a statement for healthcare professionals from the AHA/ASA Council on Stroke: co-sponsored by the Council on Cardiovascular Radiology and Intervention. Stroke . 2006;37:577-617.
Silver B. Ischemic stroke. In: Gilman S, ed. MedLink Neurology website. Available at: http://www.medlink.com . Accessed February 23, 2008.
Stroke. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/stroke/stroke.htm . Accessed June 25, 2008. Stroke (acute management). EBSCO Publishing Dynamed website.Available at:
Stroke treatment. American Heart Association website. Available at: http://www.americanheart.org . Accessed June 25, 2008.
What is stroke? National Stroke Association website. Available at:
http://www.stroke.org/site/PageServer?pagename=STROKE . Accessed June 25, 2008.
*¹11/20/06 DynaMed's Systematic Literature Surveillance http://www.dynamicmedical.com/what.php : Mas JL, Chatellier G, Beyssen B, et al. Endarterectomy versus stenting in patients with symptomatic severe carotid stenosis. N Engl J Med . 2006;355:1726-1729.
*² 12/16/2008 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Farquhar C, Marjoribanks J, Lethaby A, Suckling J, Lamberts Q. Long term hormone therapy for perimenopausal and postmenopausal women. Cochrane Database Syst Rev. 2008;CD004143.
Last reviewed February 2009 by Rimas Lukas, MD Last Updated: 3/16/2009
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