Embolic Stroke: An Overview

An embolic stroke is a type of ischemic stroke that occurs when an embolus (a blood clot that breaks off from a larger blood clot) travels from elsewhere in the body to block an artery in the brain. The other type of ischemic stroke is a thrombotic stroke, when a blood clot forms within an artery in the brain and blocks blood flow. More than 85% of strokes are ischemic.

The lack of blood supply causes nearby brain cells to become severely damaged. A stroke is a medical emergency. It can cause death and profound disability. Stroke is the fifth leading cause of death in the United States and a leading cause of disability.

Read on to learn more about the risk factors, symptoms, and treatments for embolic stroke.

When Should You Suspect an Embolic Stroke?

Whether embolic or thrombotic, ischemic strokes generally share the same symptoms.

These include:

• Numbness or weakness on one side of the body
• Difficulty walking, trouble with coordination and balance
• Dizziness, vertigo
• Slurred speech
• Difficulty using the right words and understanding language
• Nausea, vomiting
• Sudden headache with no specific cause
• Decreased vision
• Double vision

What Is the Main Cause of Embolic Stroke?

Atrial fibrillation, or AFib, is a leading cause of embolic strokes. This type of irregular heart rhythm can cause blood to pool, thicken, and clot in the heart or arteries near it. Pieces of these clots can travel to the brain. AFib accounts for about 15% of ischemic strokes.

Other, less frequent causes of embolic strokes include:

• Carotid artery disease: A piece from a blood clot in this large artery in the neck can travel to a small artery in the brain and block it.
• Infection: Some bacterial infections can lead to blood clots. This is also called a septic embolism.
• Heart tumors: A myxoma is a non-cancerous heart tumor. Pieces of the growth can break off (an embolic myxoma) and travel to an artery in the brain.
• Air in the bloodstream: An air embolism can happen after an injection, surgical procedure, or lung trauma.

Embolic Stroke Diagnosis

Stroke diagnosis begins with a physical and neurological exam. In addition to checking your vital signs (such as blood pressure), a first responder or healthcare provider will test your reflexes and check your strength, sensation, and vision.

If your healthcare provider suspects you've had a stroke, they'll confirm your diagnosis with other tests, such as:

• Computed tomography (CT) scan
• Magnetic resonance imaging (MRI) scan
• Computed tomography angiogram (CTA)
• Magnetic resonance angiography (MRA)

Treatment for Embolic Stroke

A stroke is a medical emergency. It needs to be treated as quickly as possible to minimize damage to brain tissue and prevent or limit any long-term impact.

Sometimes treatment for an ischemic stroke is aimed at clearing the blockage. In select cases, this includes the use of intravenous (IV) tissue plasminogen activator, or tPA. This drug is most effective if given within three hours after symptoms start.

Your healthcare provider may recommend surgery to remove the blockage. This procedure, called a thrombectomy, involves inserting a catheter into the artery to clear it. This procedure can be done within 24 hours of the initial symptoms but is most effective if performed within six hours after symptoms begin.

Risk Factors for Stroke

Like other ischemic strokes, embolic strokes can occur due to underlying risk factors, including:

• High blood pressure
• Smoking
• Being overweight or obese
• Sedentary lifestyle
• Diabetes

Other risk factors for stroke can include:

• Age: The chance of having a stroke approximately doubles every 10 years after age 55. While stroke is common among the elderly, a lot of people under 65 also have strokes.
• Family history: Your stroke risk may be higher if a parent, grandparent, sister, or brother has had one. 
• Race: Black people have a much higher risk of death from a stroke than White people do. This is partly due to higher risks of high blood pressure, diabetes, and obesity.
• Gender: Each year, women have more strokes than men, and stroke kills more women than men. Use of birth control pills, pregnancy, a history of preeclampsia/eclampsia or gestational diabetes, smoking, and post-menopausal hormone therapy may pose special stroke risks for women. 
• Heart attack: If you've had a heart attack, you're at higher risk of having a stroke, too.
• Prior stroke or transient ischemic attack (TIA, or mini-stroke): The risk of stroke for someone who has already had one is many times that of a person who has not. TIAs are "warning strokes" that produce stroke-like symptoms without lasting damage.

Prognosis

Strokes can be fatal or have devastating long-term consequences if not treated quickly. Because brain cells begin to die soon after blood flow is interrupted, time is critical.

Another factor that impacts how you could be affected by stroke is which artery was blocked, the duration of blockage, and which area of the brain was deprived of oxygen.

For instance, if the basilar artery is blocked, oxygenated blood may not reach the occipital lobes, brainstem, and cerebellum—areas that control functions like breathing, sight, and movement. If a person survives a basilar artery stroke, these functions could be impaired or lost.

Experts agree that rehabilitation plays a major part in stroke recovery, and should begin as soon as possible after a stroke. Individual rehabilitation plans center on returning to daily living activities and overcoming serious and potentially long-lasting impacts on cognitive, physical, and emotional health.

Summary

Embolic strokes occur when blood clots or other blockages form elsewhere in the body, travel to the brain, and interrupt blood flow. Most of the time, this type of stroke is caused by a blood clot that forms in the heart (usually due to AFib). Diagnosis is made through physical and neurological examination augmented by imaging tests (e.g., CT, MRI). Treatment typically consists of IV drug administration or surgical intervention.

Risk factors include age, race, and a previous history of stroke or heart attack. The prognosis depends on several factors such as which artery was blocked, blockage duration, and the area of the brain affected. Rehabilitation plays an important role in stroke recovery. The key to surviving an embolic stroke is prompt treatment.