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.

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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

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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.

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.