Embolic Stroke Causes, Symptoms, Diagnosis & Management

An embolic stroke is a type of ischemic stroke. It happens when a blood clot or other debris forms elsewhere in the body, travels through the bloodstream and blocks an artery in the brain.

A stroke, or cerebrovascular accident (CVA), is a sudden loss of brain function caused by a problem with the brain's blood supply. Symptoms usually start suddenly and may include weakness or numbness of the face, arm or leg, often on one side of the body. Stroke risk rises with age.

A stroke is a medical emergency. If you notice signs of a stroke, call 911 (or your local emergency number) right away. Fast treatment can save brain tissue.

Stroke or cerebrovascular disease can present as:

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• Acute focal stroke due to hemorrhage or infarction
• The gradual decline in brain function due to cerebral ischemia

Risk Factors

Some risk factors for stroke can be changed, and others cannot.

Modifiable factors

These factors can often be controlled with lifestyle changes or treatment. They include:

• Hypertension
• Cigarette smoking
• Diabetes mellitus
• Heart failure
• Atrial fibrillation and other heart rhythm or valve problems
• Hyperlipidemia
• High alcohol intake
• Oral contraceptives (especially in people who smoke)

Non-modifiable factors

These factors can't be changed or reversed. They include:

• Age
• Gender
• Genetics and family history
• History of previous heart attack, stroke or transient ischemic attack (TIA)

Mechanism of Occurrence

Strokes are divided into two major groups according to how they happen.

1- Ischemic Stroke

In an ischemic stroke, an artery supplying the brain is blocked, so blood flow drops and brain tissue is injured (cerebral infarction). The blockage may be due to:

• Thrombosis

A clot forms at the site of a fatty plaque (atherosclerosis) in an artery in the neck or brain, blocking blood flow.

• Embolism

A clot or piece of plaque forms somewhere else, breaks loose, travels to a brain artery and blocks it. This is an embolic stroke, and the traveling clot is called an embolus.

Many emboli come from the heart, especially in people with atrial fibrillation. Others come from narrowed arteries in the neck. Without blood flow, brain cells start to die within minutes, and swelling can add to the damage over the following hours.

2- Hemorrhagic stroke

This type of stroke occurs when a blood vessel in the brain bursts. It may be bleeding into the brain tissue (intracerebral hemorrhage) or bleeding around the brain, often from a ruptured aneurysm (subarachnoid hemorrhage).

Symptoms of Embolic Stroke

An embolic stroke usually starts suddenly. Some people first have a transient ischemic attack (TIA), or "mini-stroke," with symptoms that go away. A TIA is a warning sign that needs emergency care.

Embolic Stroke symptoms vary from person to person, depending on the part of the brain involved. Not every patient has every symptom.

• Sudden weakness or paralysis, often on one side of the body
• Weakness of one or more limbs
• Facial drooping
• Difficulty speaking or aphasia
• Difficulty understanding words
• Numbness in the limbs
• Sudden vision problems
• Difficulty walking, dizziness or loss of balance
• Difficulty with coordination

Remember BE FAST: Balance, Eyes, Face, Arms, Speech, Time to call 911.

How Embolic Stroke Is Diagnosed?

Tests are done quickly to confirm a stroke, rule out bleeding, and find the cause. Your doctor may use the following tests.

• CT scan

This is usually the first test. A CT scan of the brain shows whether there is bleeding, which changes the treatment. A CT angiogram can show blocked vessels.

• MRI

MRI uses a magnetic field and radio waves to show damaged brain tissue in detail.

• Echocardiogram

This ultrasound of the heart looks for blood clots or other sources of emboli in the heart.

• Carotid ultrasound

This ultrasound shows blood flow in the neck arteries and any plaque in the carotid arteries.

Heart rhythm monitoring (ECG) is also used to look for atrial fibrillation.

Management Of Embolic Stroke

Stroke treatment is decided by the emergency and stroke team. The information below is general and is not a guide to treating a patient.

1- Emergency treatment

Here are the main emergency treatments:

• Clot-busting medicine (thrombolysis)

A medicine called tissue plasminogen activator (tPA) can dissolve the clot. It must be given soon after symptoms start, usually within 3 to 4.5 hours, and only after bleeding in the brain has been ruled out.

• Mechanical thrombectomy

For a large blocked artery, doctors may thread a thin tube through a blood vessel to remove the clot. This may be possible up to 24 hours after symptoms start in selected patients.

• Blood pressure management

Blood pressure is closely watched. Doctors avoid lowering it too fast in an ischemic stroke, because blood flow to the brain is already reduced.

2- Supportive care

Here are the General Measures:

• Careful nursing

Patients are positioned to protect the airway and prevent aspiration.

• Maintenance of airway

The care team makes sure the patient can breathe and checks swallowing before allowing food or drink.

• Fluids and nutrition

If the patient can't swallow safely, fluids are given through a vein and nutrition through a feeding tube.

• Care of skin

Skin is kept clean and dry, and patients are turned regularly to prevent pressure sores.

• Care of bladder and bowel

Some patients need a catheter or help with constipation.

• Care of eyes

Unconscious patients need eye care to keep the eyes from drying out.

• Physiotherapy

Rehabilitation starts early, with movement to prevent stiff joints and to help regain strength, speech and daily skills.

3- Preventing another stroke

Here are the long-term treatments:

• Antiplatelet therapy

Medicines such as aspirin may be prescribed to prevent new clots, once a hemorrhagic stroke is ruled out. Don't take aspirin for a suspected stroke unless medical staff tell you to, since some strokes are caused by bleeding.

• Anticoagulants

Blood thinners (anticoagulants) are often used when the clot came from the heart, such as in atrial fibrillation.

• Statins

Statins lower cholesterol and are often prescribed after an ischemic stroke.

• Treating the cause

Doctors treat high blood pressure, diabetes and heart problems, and sometimes operate on a narrowed carotid artery. Quitting smoking and limiting alcohol also lower the risk.

Sources

• Stroke Treatment, NHLBI (NIH)
• Embolic Stroke, Cleveland Clinic
• Treatment for a stroke, NHS