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

See also:

• Arteriovenous malformation (AVM)
• Hemorrhagic stroke
• Stroke secondary to carotid dissection (bleeding from the carotid arteries)
• Stroke secondary to carotid stenosis (narrowing of the carotid arteries)
• Stroke secondary to cocaine use
• Stroke secondary to FMD (fibromuscular dysplasia)
• Stroke secondary to syphilis

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

Approximately every 40 seconds, someone in the United States has a stroke. A stroke can happen when the following occurs:

• A blood vessel that supplies 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 called 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

Ischemic stroke 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) Fat, cholesterol, and other substances collect on the wall of the arteries, forming a sticky substance called plaque. Over time, the plaque builds up. This often makes it hard for blood to flow properly, 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 blood to the brain is called a cerebral embolism.

Watch this video about: Stroke

Other causes of ischemic stroke include:

• Abnormal heart valve
• Inflammation of the inside lining of the heart chambers and heart valves ( endocarditis)
• Mechanical heart valve

A clot can form on a heart valve, break off, and travel to the brain. For this reason, those with mechanical or abnormal heart valves often must take blood thinners.

Watch this video about: Stroke - secondary to cardiogenic embolism

HEMORRHAGIC STROKE

A second major cause of stroke is bleeding in the brain. This is called a hemorrhagic stroke. It can occur when small blood vessels in the brain become weak and burst. Some people have defects in the blood vessels of the brain that make this more likely. The flow of blood that occurs after the blood vessel ruptures damages brain cells.

STROKE RISKS

High blood pressure is the number one risk factor for strokes. The following also increase your risk for stroke:

• Diabetes
• Family history of stroke
• Heart disease
• High cholesterol
• Increasing age

Watch this video about: Hypertension - overview

Certain medications make blood clots more likely, and therefore your chances for a stroke. Birth control pills can increase the chances blood clots, especially in woman who smoke and who are older than 35.

Men have more strokes than women. But, women have a risk of stroke during pregnancy and the weeks immediately after pregnancy.

The following can increase the risk of bleeding into the brain, which makes you more likely to have a stroke:

• Alcohol use
• Bleeding disorders
• Cocaine use
• Head injury

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.

Symptoms usually develop suddenly and without warning. They may be episodic (occurring and then stopping) or they may slowly get worse over time.

Symptoms may include:

• Change in alertness (consciousness)
  • Coma
  • Lethargy
  • Sleepiness
  • Stupor
  • Unconsciousness
  • Withdrawn
• Difficulty speaking or understanding others
• Difficulty swallowing
• Difficulty writing or reading
• Headache
  • Occurs when lying flat
  • Wakes you up from sleep
  • Gets worse when you change positions or when you bend, strain, or cough
  • Starts suddenly
• Loss of coordination
• Loss of balance
• Movement changes, usually on only one side of the body
  • Difficulty moving any body part
  • Loss of fine motor skills
• Nausea or vomiting
• Seizure
• Sensation changes, usually on only one side of the body
  • Decreased sensation
  • Numbness or tingling
• Suddent confusion
• Weakness of any body part
• Vision changes
  • Decreased vision
  • Loss of all or part of vision

Knowing how the symptoms developed is important when it comes to diagnosing a stroke. Symptoms may be severe at the beginning of the stroke, or they may slowly get worse or occur off and on for the first day or two.

A neurological exam may suggest increased intracranial pressure or decreased brain function. The person's specific symptoms can help tell which part of the brain is affected.

An eye exam may show swelling of the optic nerve from pressure in the brain, or there may be changes in eye movement. Abnormal reflexes may be present.

The health care provider may hear an abnormal sound, called a "bruit," when using a stethoscope to listen to the carotid arteries in the neck.

Tests can help your doctor determine the type, location, and cause of the stroke and to rule out other disorders that may be responsible for the symptoms. Tests may include:

• Angiogram of the head to see which blood vessel is blocked or bleeding and help your doctor decide if the artery can be reopened using a thin tube
• Complete blood count (CBC)
• Bleeding time
• Blood clotting tests (Prothrombin time or partial thromboplastin time)
• Electrocardiogram (ECG) to diagnose underlying heart disorders
• Echocardiogram if the stroke may have been caused by a blood clot from the heart
• Carotid duplex (a type of ultrasound) if narrowing of the neck arteries (carotid stenosis) led to the stroke
• Head CT or head MRI or newer tests, called magnetic resonance angiography (MRA) or CT angiography, to determine the location and severity of the stroke and which blood vessel is blocked or bleeding
• Heart monitoring to determine if an irregular heart beat (such as atrial fibrillation) caused the stroke

Additional support and resources are available from the American Stroke Association -- www.strokeassociation.org.

The outlook depends on the type of stroke and how quickly treatment is received. Recovery may occur completely, or there may be some permanent loss of function.

• Breathing in a food into the airway (aspiration)
• Decreased life span
• Difficulty communicating
• Permanent loss of brain functions
• Permanent loss of movement or sensation in one or more parts of the body
• Problems due to loss of mobility, including joint contractures and pressure sores
• Fractures
• Malnutrition
• Muscle spasticity
• Reduced ability to function or care for self
• Reduced social interactions
• Side effects of medications

Stroke is a medical emergency that requires immediate treatment. Call your local emergency number (such as 911) if someone has symptoms of a stroke.

To help prevent a stroke:

• Avoid fatty foods. Follow a healthy, low-fat diet.
• Do not drink more than 1 to 2 alcoholic drinks a day.
• Exercise regularly: 30 minutes a day if you are not overweight; 60 - 90 minutes a day if you are overweight.
• Get your blood pressure checked every 1 - 2 years, especially if high blood pressure runs in your family.
• Have your cholesterol checked. If you are at high risk for stroke, your LDL "bad" cholesterol should be lower than 100 mg/dL. Your doctor may recommend that you try to reduce your LDL cholesterol to 70 mg/dL.
• Follow your doctor's treatment recommendations if you have high blood pressure, diabetes, high cholesterol, and heart disease.
• Quit smoking.

Aspirin therapy (81mg a day or 100mg every other day) is recommended for stroke prevention in women under 65 as long as the benefits outweigh the risks. It should be considered for women over age 65 only if their blood pressure is controlled and the benefit is greater than the risk of gastrointestinal bleeding and brain hemorrhage. Ask your doctor if aspirin is right for you.

Your doctor may also recommend aspiring therapy or another blood thinner if you have had a transient ischemic attach (TIA) or stroke in the past or if you currently have:

• Congestive heart failure
• Irregular heart beat (such as atrial fibrillation)
• Mechanical heart valve
• Other risk factors for stroke

A type of surgery calledcarotid endarterectomy may help prevent new strokes from occurring in persons with large blockages in their neck arteries.

Goldstein LB. Prevention and management of stroke. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Libby: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Saunders;2007:chap 58.

Zivin JA. Hemorrhagic cerebrovascular disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 432.