Embolic Stroke

Overview

Embolic strokes are also ischemic strokes. They are caused by blockage of one of the arteries to the brain by a blood clot that has formed elsewhere (usually in the heart), broken free, and traveled to the brain as an embolus. Sometimes the clot can form in the aorta, which is the largest artery in the body. These clots can travel to any artery in the brain, but more often they block the larger arteries, causing more severe strokes. Embolic strokes can cause any of the typical symptoms of ischemic stroke.

Symptoms

The five most common symptoms of a stroke are:
  1. Sudden weakness or numbness of face, arm or leg; especially if the numbness is all on one side of the body
  2. Sudden confusion, trouble speaking or understanding
  3. Sudden trouble seeing in one or both eyes
  4. Sudden trouble walking, dizziness, loss of balance or coordination
  5. Sudden severe headache with no known cause
If you or someone you know may be having a stroke, call 911 immediately.

Causes

An embolic stroke, which is a type of ischemic stroke, is caused by blockage of a blood vessel (artery) supplying the brain. Brain tissue that no longer receives its blood supply can die within a few hours unless something is done to stop the damage. Ischemic stroke represents about 80 percent of all strokes in the United States.

The blockage of arteries can occur in large arteries in the neck or the base of the brain, or in small arteries inside the brain itself. A blood clot can form in the brain or it can form elsewhere and be carried to the brain by an artery.  As many as 20 percent of victims die in the month after having an ischemic stroke, and the majority of survivors have some long-term disability.

Risk Factors

There are many conditions that increase a person’s risk of ischemic stroke. These include high blood pressure, heart disease, high cholesterol, diabetes, smoking and an unhealthy lifestyle. Treating these conditions can decrease stroke risk.

Diagnosis

The doctors will need to make sure that the symptoms you are experiencing are due to a stroke. In order to do this, the doctors will find out more about you by asking you and your family about your medical problems and about the symptoms you are experiencing.
You will likely have an EKG to assess your heart rhythm and activity. The doctors will need to do a physical exam and draw some blood to send to the laboratory.

Pictures of your brain will also be obtained in most circumstances. The pictures of your brain will help to determine if you are having an ischemic stroke (blockage without bleeding) or if you have bleeding in or around your brain (hemorrhagic stroke).

Pictures of your brain may be obtained using any of the following:
Computed tomography (CT scan): A CT scan may be normal if it is done soon after the onset of symptoms. A CT scan is the best test to look for bleeding in or around your brain. In some hospitals, a perfusion CT scan may be done to see where the blood is flowing and not flowing in your brain.

Magnetic resonance imaging (MRI scan): A special MRI technique (diffusion MRI) may show evidence of an ischemic stroke within minutes of symptom onset. In some hospitals, a perfusion MRI scan may be done to see where the blood is flowing and not flowing in your brain.

Angiogram: a test that looks at the blood vessels that feed the brain. An angiogram will show whether the blood vessel is blocked by a clot, the blood vessel is narrowed, or if there is an abnormality of a blood vessel known as an aneurysm.

Carotid duplex: A carotid duplex is an ultrasound study that assesses whether or not you have atherosclerosis (narrowing) of the carotid arteries. These arteries are the large blood vessels in your neck that feed your brain.

Transcranial Doppler (TCD): A TCD is an ultrasound study that assesses whether or not you have atherosclerosis (narrowing) of the blood vessels inside of your brain. A TCD can also be used to see if you have emboli (blood clots) in your blood vessels.

Echocardiogram: An echocardiogram is an ultrasound study of the heart. It can be done by placing the ultrasound probe on your chest (a transthoracic echocardiogram) or in your throat (a transesophageal echocardiogram). The purpose of an echocardiogram is to see if there are blood clots in your heart that may have led to your stroke.

Complications

Common complications resulting from a stroke are:
  • Urinary tract infection
  • Bladder control
  • Pneumonia
  • Brain swelling
  • Seizures
  • Depression
  • Bedsores
  • Fatigue
Common conditions resulting from a stroke are:

  • Difficulty speaking or understanding speech (aphasia)
  • Difficulty with movement on one side of the body (hemiparesis)
  • Difficulty with sensation on one side of the body (hemisensory deficit)
  • Difficulty with thinking and/or paying attention to the world around you
The team of health-care professionals caring for you in the hospital has many options available to treat these complications.

Recovery

Movement of the extremities is often impaired after a stroke, but the ability to move usually improves substantially during the first months after the stroke and can continue to improve for some time thereafter. Recovery takes longer when there is serious impairment of movement. Most patients will have some remaining impairment of motion following their stroke.  Speech ability also is often impaired after a stroke. Speech improves in most patients. Some patients continue to show improvement for months or years afterward.

Strokes can be very different for different people, and the effects will vary depending on what part of the brain is injured. Because of this, it is not easy to generalize about the extent of improvement that you can expect. In addition, the patient’s outcome will depend on his/her general health. A healthy, active, young person will have a better outcome than an elderly, ill person.

If a person has only mild symptoms during the first few days after a stroke, they will generally be able to function better after recovery than a person who had severe symptoms after their stroke. Younger patients will have better recovery than elderly patients. The larger the area of damage to the brain, the less chance there is of getting full recovery.

When brain cells die as a result of a stroke, the body removes the dead cell debris. The brain function that has been impaired by the stroke can recover.  Undamaged brain areas near the area of the stroke may have impaired function as a result of the loss of normal communication with the damaged tissue. But after time, these regions resume their activity and some of the functions that were performed by the damaged area can be taken over by a neighboring healthy area of the brain and allow recovery to occur.
In the normal brain, an activity, such as pointing a finger, is the result of coordinated activity in many different parts of the brain. When a stroke damages one part of this network of activity, the remaining parts of the brain increase their activity in an effort to recover the function.

In addition, there are two brain hemispheres and when an area in one hemisphere is damaged, many patients start to use both sides of the brain to perform a task.

Today, good medical care allows the brain to heal after a stroke. Physical, occupational and speech therapy all play an important role in patients that have disabilities from their stroke. Family and other caregivers are vital to support the patient’s efforts toward recovery.

The brain has mechanisms to repair itself, but scientists are just beginning to understand them. The results from some experimental studies show that some medicines that stimulate brain cell activity or cause brain cells to grow can increase recovery from stroke. In other studies, introducing cells into the brain can promote recovery.  There are many reasons to be optimistic about meaningful recovery after a stroke.

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