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Left-side Stroke by Rebecca J. Stahl, MA

Definition

The cerebrum, the largest part of the brain, is separated into the right and left hemispheres. In most people, the left hemisphere is in charge of the functions on the right-side of the body, as well as the ability to speak, use language, and other abilities.

A left-side stroke happens when the brain’s blood supply is interrupted in this area. Without oxygen and nutrients from blood, the brain tissue quickly dies. A stroke is a serious condition. It requires emergency care.

Causes

There are two main types of stroke:

Ischemic
Hemorrhagic

An ischemic stroke (the more common form) is caused by a sudden decrease in blood flow to a region of the brain, which may be due to:

A clot that forms in another part of the body (eg, heart or neck) breaking off and blocking the flow in a blood vessel supplying the brain (embolus).
A clot that forms in an artery that supplies blood to the brain (thrombus)
A tear in a blood vessel supplying a part of the brain (arterial dissection)

A hemorrhagic stroke is caused by a burst blood vessel that results in bleeding in the brain.

Hemorrhagic vs. Ischemic Stroke

Risk Factors

Examples of risk factors that you can control or treat include:

Certain conditions, like:
- High blood pressure
- High cholesterol
- High levels of the amino acid homocysteine (may lead to blood clots)
- Atherosclerosis (narrowing of the arteries due to build-up of plaque)
- Atrial fibrillation (abnormal heart rhythm)
- Obesity
- Metabolic syndrome
- Type 2 diabetes
- Alcohol or drug abuse

Medicines (eg, long-term use of birth control pills )
Lifestyle factors
- Smoking
- Physical inactivity
- Diet high in sodium and processed foods

Risk factors that you cannot control include:

History of stroke , heart attack , or other type of cardiovascular disease
History of transient ischemic attack (TIA)—With a TIA, stroke symptoms often resolve within minutes (and always within 24 hours). They may signal a very high risk of having a stroke in the future.
Age: 60 or older
Family members who have had a stroke
Gender: males
Race: Black, Asian, Hispanic
Blood disorder that increases clotting
Heart valve disease (eg, mitral stenosis )

Symptoms

The immediate symptoms of a left-side stroke come on suddenly and may include:

Weakness or numbness of face, arm, or leg, especially on the right side of the body
Confusion
Trouble speaking or understanding ( aphasia )
Dizziness, loss of balance
Vision problems (on the right side of vision in both eyes)
Difficulty swallowing
Headache

If you or someone you know has any of these symptoms, call 911 right away. A stroke needs to be treated as soon as possible.

Longer-lasting effects of the stroke may include problems with:

Movement on the right-side of the body
Speaking, understanding language, reading, and writing
Organizing, analyzing, reasoning, planning
Memory and learning
Completing tasks (difficulty doing activities, difficulty planning)
Short attention span
Vision (difficulty seeing out of the right field of vision)
Mental health (eg, depression , cautiousness, compulsive behavior, lack of motivation, frustration)

Diagnosis

The doctor will make a diagnosis as quickly as possible. Tests may include:

Exam of nervous system
Computed tomography (CT) scan —a type of x-ray that uses a computer to make pictures of the brain
CT angiogram—a type of CT scan that evaluates the blood vessels in the brain and/or neck
Magnetic resonance imaging (MRI) —a test that uses magnetic waves to make pictures of the brain
Magnetic resonance angiography (MRA) —a type of MRI scan that evaluates the blood vessels in the brain and/or neck
Angiogram —a test that uses a catheter (tube) and x-ray machine to assess the heart and its blood supply
Heart function tests (eg, electrocardiogram , echocardiogram )
Doppler ultrasound —a test that uses sound waves to examine blood vessels
Blood tests
Tests to check the level of oxygen in the blood
Kidney and liver function tests
Tests to evaluate the ability to swallow

Treatment

Immediate treatment is needed to:

Dissolve or remove a clot causing an ischemic stroke
Stop the bleeding during a hemorrhagic stroke

In some cases, oxygen therapy is needed.

Medications

Medicines may be given right away for an ischemic stroke to:

Dissolve clots and prevent new ones from forming
Thin blood
Control blood pressure
Reduce brain swelling
Treat an irregular heart rate

For a hemorrhagic stroke, the doctor may give medicines to:

Work against any blood-thinning drugs that you may regularly take
Reduce how your brain reacts to bleeding
Control blood pressure
Prevent seizures

Surgery

For an ischemic stroke, procedures may be done to:

Reroute blood supply around a blocked artery
Remove the clot or deliver clot-dissolving medicine
Remove fatty deposits from a carotid artery (major arteries in the neck that lead to the brain)
Widen carotid artery and add a mesh tube to keep it open (eg, carotid angioplasty or stenting )

For a hemorrhagic stroke, the doctor may:

Remove a piece of the skull to relieve pressure on the brain and remove the blood clot
Place a clip or tiny coil in the aneurysm to stop it from bleeding

Rehabilitation

A rehabilitation program focuses on:

Physical therapy—to regain as much movement as possible
Occupational therapy—to assist in everyday tasks and self-care
Speech therapy—to improve swallowing and speech challenges
Psychological therapy—to help adjust to life after the stroke

Prevention

To help reduce your chance of having a stroke, take the following steps:

Exercise regularly .
Eat a healthy diet that includes fruits, vegetables, whole grains, and fish.
Maintain a healthy weight.
Drink alcohol only in moderation (1-2 drinks per day).
If you smoke, quit .
If you have a chronic condition, like high blood pressure or diabetes, get proper treatment.
If recommended by your doctor, take a low-dose aspirin every day.
If you are at risk for having a stroke, talk to your doctor about statin medicines.

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/splash/
Stroke Survivors Association of Ottawa http://www.strokesurvivors.ca/

References:

Am I at risk for a stroke? National Stroke Association website. Available at: http://www.stroke.org/site/PageServer?pagename=risk . Accessed April 22, 2011.
Anatomy of the brain. The University Hospital website. Available at: http://www.theuniversityhospital.com/stroke/anatomy.htm . Accessed April 22, 2011.
Effects of left middle cerebral artery stroke. Ohio State University Medical Center website. Available at: http://medicalcenter.osu.edu/PatientEd/Materials/PDFDocs/dis-cond/stroke/LeftMidCerebralArteryStroke.pdf . Accessed April 15, 2011.
Effects of stroke. Magee Rehabilitation website. Available at: http://www.mageerehab.org/effects-of-stroke.php . Accessed April 22, 2011.
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Stroke effects. American Hear Association website. Available at: http://www.americanheart.org/presenter.jhtml?identifier=4761 . Accessed April 22, 2011.
Stroke facts. St. John’s Hospital website. Available at: http://www.st-johns.org/services/stroke_center/stroke_facts.aspx . Accessed April 22, 2011.
Stroke: treatments and drugs. Mayo Clinic website. Available at: http://www.mayoclinic.com/health/stroke/DS00150/DSECTION=treatments-and-drugs . Accessed July 1, 2010. Accessed April 22, 2011.
Types of stroke. NYU Medical Center website. Available at: http://www.med.nyu.edu/strokecenter/aboutstroke/types/ . Updated November 15, 2010. Accessed April 22, 2011.
Wood D. Stroke. EBSCO Health Library website. Available at: http://www.ebscohost.com/healthLibrary/ . Updated March 28, 2011. Accessed April 22, 2011.

Last reviewed June 2012 by Rimas Lukas, MD

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