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 neurologic functions. The types of functions that are affected will depend on the part of the brain that is damaged.

Two blood flow problems that cause a stroke. Strokes may be hemorrhagic or ischemic.

• A hemorrhagic stroke is caused by a ruptured blood vessel. It may be:

  • Intracerebral hemorrhage—bleeding in the brain
  • Subarachnoid hemorrhage

    —bleeding in the tissue around the brain

• An ischemic stroke is caused by a blocked blood vessel.

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Causes

A hemorrhagic stroke can occur because of abnormal blood vessels in the brain. These vessels are weaker than normal vessels and break open under pressure. The blood leaks out of the broken blood vessel and into the brain. This can lead to brain damage because blood flow is interrupted and the pooled blood can cause pressure on the brain.

Blood vessels may be weakened by:

• Abnormality in blood vessel structure
• Arterio-venous (AV) malformation

  —an abnormal knot of blood vessels

• Aneurysm

  —a weakened spot in a blood vessel wall

• Other illness or medical conditions like

  hypertension

Blood vessels damage can also be caused by trauma like a blow to the head or a car accident.

Risk Factors

Factors that may increase your chance of stroke include:

• Gender: Men are more likely to have a stroke than women
• Age: Risk of stroke increases with age particularly after 55 years of age.
• Family history of stroke

Factors that can weaken your blood vessels and increase your risk of hemorrhagic stroke include:

• Having a vessel abnormality
• High blood pressure
• Smoking
• Sleep apnea
• Cocaine use
• Alcohol use disorder

Blood disorders or medications that reduce blood clotting can also increase your risk of a hemorrhagic stroke.

Symptoms

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 symptoms.

Symptoms will depend on the part of the brain affected. Call for emergency medical services right away for:

• Sudden weakness or numbness of face, arm, or leg, especially on one side of the body
• Sudden confusion
• Sudden trouble speaking or understanding
• Sudden trouble seeing in one or both eyes

• Sudden

  dizziness, trouble walking, loss of balance, or coordination

• Sudden severe headache with no known cause
• Loss of consciousness

Other symptoms that may go along with the above symptoms include:

• Neck stiffness
• Nausea or vomiting
• Sensitivity to light

Diagnosis

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

CT scan

may be done to confirm the diagnosis.

Detailed images of blood vessels will help identify the cause of the bleeding. Images may be taken with one or more of the following tests:

• MR angiography
• CT angiogram
• Conventional angiogram
• Doppler ultrasound

Blood tests can also help identify clotting problems in the blood. Your doctor may also examine the fluid that surrounds your brain and spine.

Treatment

Immediate treatment is needed to stop the bleeding and relieve pressure on the brain.

Prevention

Management and monitoring of medical conditions like aneurysms and high blood pressure can prevent complications like stroke.

Other habits that may reduce your risk of stroke include:

• Getting regular exercise.
• Eating more fruits, vegetables, and whole grains.
• Limiting dietary salt and fat.
• Quitting smoking.
• Drinking alcohol only in moderation (1-2 drinks per day).
• Maintaining a healthy weight.
• Check blood pressure frequently. Follow your doctor’s recommendations for keeping it in a safe range.
• Stop the use of recreational drugs (such as cocaine).

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

Public Health Agency of Canada http://www.phac-aspc.gc.ca

Hemorrhagic stroke. The Children’s Hospital of Philadelphia website. Available at:
http://www.chop.edu/conditions-diseases/hemorrhagic-stroke#.VYl2_RtViko
Accessed June 7, 2013.

Hemorrhagic stroke. National Stroke Association. Available at:
http://www.stroke.org/understand-stroke/what-stroke/hemorrhagic-stroke?pagename=HEMSTROKE
Accessed June 10, 2013.

Intracerebral hemorrhage. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated March 21, 2013. Accessed June 6, 2013.

Stroke (acute management). EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated May 2, 2013. Accessed June 6, 2013.

Stroke treatments. American Heart Association American Stroke Association website. Available at:
http://www.strokeassociation.org/STROKEORG/AboutStroke/Treatment/Stroke-Treatments_UCM_310892_Article.jsp
Update May 23, 2103. Accessed June 7, 2013.

Subarachnoid hemorrhage. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated January 22, 2013. Accessed June 6, 2013.

8/11/2015 DynaMed’s Systematic Literature Surveillance
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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].