Definition

Stroke is a brain injury caused by an interruption in blood flow. Brain tissue that does not get oxygen and nutrients from blood can die within minutes. The damage to the brain can cause a sudden loss in bodily functions. The types of function that are affected will depend on the part of the brain that is damaged.

There are two blood flow problems that cause a stroke. Strokes may be ischemic or hemorrhagic.

• An ischemic stroke is caused by a blocked blood vessel. It is the most common cause of stroke.
• A hemorrhagic stroke is caused by a ruptured blood vessel.

Causes

An ischemic stroke occurs when something stops the flow of blood. It may be a buildup or swelling of the walls of the blood vessels and/or something in the blood that becomes stuck in the blood vessel. A blockage in a small blood vessel will affect a smaller area of the brain. A blockage in larger blood vessels can block the flow of blood to several smaller blood vessels, leading to more brain damage.

The blockage may be the result of one or more of the following:

• Atherosclerosis —a build-up of fatty substances along the inner lining of the artery that gradually decrease the area the blood can flow through
• A blood clot that has traveled from other parts of the body such as the neck or heart
• Inflammation of the blood vessels

Risk Factors

Certain factors increase your risk of stroke but can not be changed, such as:

• Race—People of African American, Hispanic, or Asian/Pacific Islander descent are at increased risk.
• Age: Older than 55 years of age
• Family history of stroke

Other factors that may increase your risk can be changed such as:

• Drug abuse from cocaine, amphetamines, or heroin use
• Smoking
• Physical inactivity

Certain medical condition that can increase your risk of stroke. Management or prevention of these conditions can significantly decrease your risk. Medical conditions include:

• High blood pressure
• High cholesterol levels —specifically high-LDL bad cholesterol
• Low bone mineral density, especially in women
• Obesity and metabolic syndrome
• Sleep apnea
• High blood homocysteine level
• Atherosclerosis
• Diabetes mellitus or impaired glucose tolerance
• Atrial fibrillation
• Blood disorders such as sickle cell disease and polycythemia
• Vascular dementia
• Disease of heart valves, such as mitral stenosis
• Prior stroke or cardiovascular disease, such as heart attack
• Peripheral artery disease
• Transient ischemic attack (TIA) —a warning stroke with stroke-like symptoms that go away shortly after they appear
• Conditions that increase your risk of blood clots such as:
  • Cancer
  • Certain autoimmune diseases
• Migraine with aura
• Having a blood vessel abnormality

Risk factors specific to women include:

• Previous pre-eclampsia
• Use of birth control pills, especially if you are over 35 years old and smoke
• Long-term use of hormone replacement therapy
• Menopause
• Pregnancy—due to increased risk of blood clots

Symptoms

Symptoms occur suddenly. Exact symptoms will depend on the part of the brain affected. Rapid treatment is important to decrease the amount of brain damage. Brain tissue without blood flow dies quickly.

Call for emergency medical services right away if you notice any of the following sudden symptoms:

• Weakness or numbness of face, arm, or leg, especially on one side of the body
• Confusion
• Trouble speaking or understanding
• Trouble seeing in one or both eyes
• Lightheadedness, trouble walking, loss of balance, or coordination
• Severe headache with no known cause

Diagnosis

A physical exam will be done to look for muscle weakness, visual and speech problems, and movement difficulty. If possible, you will be asked about your symptoms and medical history.

Images may be taken of your bodily structures. This can be done with:

• CT scan
• MRI scan
• Magnetic resonance angiography (MRA)
• CT angiogram (CTA)
• Doppler ultrasound

Blood tests can also help determine if there is a bleeding problem.

Treatment

Immediate treatment is needed to open the blocked blood vessel. This should restore blood flow to the brain tissue and stop further damage.

Treatment after immediate care will aim to:

• Reduce the chance of later strokes
• Improve function affected by the stroke
• Overcome disabilities

Supportive care may also include:

• Oxygen therapy
• Precautions to prevent choking

Prevention

Many of the risk factors for stroke can be changed. Lifestyle changes that can help reduce your chance of getting a stroke include:

• Exercise regularly.
• Eat more fruits, vegetables, and whole grains. Limit dietary salt and fat.
• Stop smoking.
• Increase your consumption of fish.
• Drink alcohol only in moderation: no more than 1-2 drinks per day.
• Maintain a healthy weight.
• Check blood pressure frequently. Follow your doctor’s recommendations for keeping it in a safe range.
• Take a low dose of aspirin if your doctor says it is safe.
• Keep chronic medical conditions under control. This includes high cholesterol and diabetes.
• Talk to your doctor about the use of a statins. These types of drugs may help prevent certain kinds of strokes in some people.
• Seek medical care if you have symptoms of a stroke, even if symptoms stop.
• If you abuse drugs, talk to your doctor about rehabilitation programs.

National Stroke Association http://www.stroke.org

Heart and Stroke Foundation http://www.heartandstroke.com

Ischemic strokes (clots). American Heart Association American Stroke Association website. Available at:
http://www.strokeassociation.org/STROKEORG/AboutStroke/TypesofStroke/IschemicClots/Ischemic-Strokes-Clots_UCM_310939_Article.jsp
Updated August 29, 2014. Accessed November 18, 2014.

Long term management of stroke. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated September 30, 2014. Accessed November 18, 2014.

Nueroimaging for acute stroke. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated October 14, 2014. Accessed November 18, 2014.

Recognizing stroke. National Stroke Association website. Available at:
http://www.stroke.org/site/PageServer?pagename=SYMP
Accessed November 18, 2014.

Stroke (acute management). EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated October 17, 2014. Accessed November 18, 2014.

11/20/06 DynaMed’s Systematic Literature Surveillance
http://www.ebscohost.com/dynamed:
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.

12/16/2008 DynaMed’s Systematic Literature Surveillance
http://www.ebscohost.com/dynamed:
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.

10/9/2009 DynaMed’s Systematic Literature Surveillance
http://www.ebscohost.com/dynamed:
Mitchell PH, Veith RC, Becker KJ, et al. Brief psychosocial-behavioral intervention with antidepressant reduces poststroke depression significantly more than usual care with antidepressant: living well with stroke: randomized, controlled trial. Stroke. 2009;40:3073-3078.

3/28/2011 DynaMed’s Systematic Literature Surveillance
http://www.ebscohost.com/dynamed:
Park Y, Subar AF, Hollenbeck A, Schatzkin A. Dietary Fiber Intake and Mortality in the NIH-AARP Diet and Health Study. Arch Intern Med. 2011 Feb 14. [Epub ahead of print]

2/7/2014 DynaMed’s Systematic Literature Surveillance
http://www.ebscohost.com/dynamed:
Bushnell C, et al. AHA/ASA Guideline for the Prevention of Stroke in Women. Stroke. 2014 Feb 6. [Epub ahead of print]

6/2/2014 DynaMed’s Systematic Literature Surveillance
http://www.ebscohost.com/dynamed:
Myint PK, Cleark AB, et al. Bone mineral density and incidence of stroke: European prospective investigation into cancer-norfolk population-based study, systemic review, and meta-analysis. Stroke. 2014 Feb;45(2):373-82.

6/2/2014 DynaMed’s Systematic Literature Surveillance
http://www.ebscohost.com/dynamed:
Imfeld P, Bodmer M, et al. Risk of incident stroke in patients with Alzheimer disease or vascular dementia. Neurology. 2013 Sep 3;81(10):910-919.

8/11/2015 DynaMed’s Systematic Literature Surveillance
http://www.ebscohost.com/dynamed:
Molnar MZ, Mucsi I, Novak M, et al. Association of incident obstructive sleep apnoea with outcomes in a large cohort of US veterans. Thorax. 2015 Jun 2 [Epub ahead of print].