An embolic stroke is caused by a blood clot that breaks loose somewhere in the body and travels into the brain through blood vessels. Once in the brain, the blood clot gets lodged in an artery, resulting in an embolic stroke. Embolic strokes are a type of ischemic stroke, which occur when arteries in the brain become blocked and account for 80 percent of all strokes. The brain relies on arteries to bring in blood, which carries the oxygen and nutrients it needs to keep functioning. When an artery is blocked, and oxygen lost, cellular death can occur.
Causes, risk factors, and symptoms of an embolic stroke
The blood clot that causes the embolic stroke can originate from anywhere in the body, but it most often comes from the heart or somewhere in the upper chest or neck. The blockage created when it enters a blood vessel too small to pass through is called an embolus. Emboli are created from air bubbles, fat, and plaque found in the vessel wall. They can also be caused by an irregular heartbeat, which is called atrial fibrillation.
Conditions that increase the risk of stroke include high blood pressure, heart disease, high cholesterol, diabetes, smoking, and an unhealthy lifestyle.
The most common symptoms of a stroke include:
- Weakness or numbness in the face, arm, or leg
- Confusion and trouble speaking or understanding words
- Difficulty seeing in one or both eyes
- Trouble walking, loss of balance or coordination
- Sudden severe headache with no known cause
- Temporary paralysis
- Stiff muscles
- Lethargy or severe sleepiness
- Slurred speech
- Feelings of dizziness or faintness
- Trouble swallowing
Symptoms will generally come on very suddenly and all at once. If you feel any of these symptoms come on, you should call for emergency medical attention.
Complications of an embolic stroke
A stroke can have long-term repercussions on your overall health. Common complications derived from a stroke include brain edema or the swelling of the brain, pneumonia, urinary tract infection, seizures, depression, bedsores, limb contractures or muscle shortening due to infrequent movement in the affected area, shoulder pain, and deep vein thrombosis or blood clots in the legs. A stroke could also induce difficulty speaking and understanding speech (aphasia), difficulty moving one side of the body (hemiparesis), and lack of sensation on one side of the body (hemisensory deficit).
How to diagnose and treat embolic stroke
Any kind of stroke is a life-threatening medical emergency and should be treated immediately. Diagnosis can take several different routes, but most often includes blood tests and brain imaging. Blood tests can determine how quickly the patient’s blood normally clots, whether there is a critical chemical imbalance in the blood, the patient’s blood sugar levels, and if there is an infection. Some doctors may also examine the heart to determine any causes that may be related to the stroke.
Common brain imaging techniques include:
- Computed tomography (CT) scan: CT scans use x-rays to create a map of the blood vessels in the brain and neck.
- Magnetic resonance imaging (MRI): MRIs use radio waves to determine if any brain tissue has been damaged due to stroke or hemorrhaging.
- Carotid duplex/ultrasound: Using detailed images, a carotid duplex or carotid ultrasound test can show the patient’s blood flow and provide a view of any fat deposits in the carotid arteries.
- Cerebral angiogram: This test involves inserting a catheter through a small incision and into the carotid or vertebral arteries. A doctor can then see a detailed view of the arteries in the brain and neck. This test looks at the blood vessels that feed the brain. It will show whether the blood vessel is blocked by a clot, narrowed, or if there is an abnormality of a blood vessel known as an aneurysm.
- Echocardiogram: This uses sound waves to find the location of any blood clots that may have traveled into the brain from elsewhere in the body.
- Transcranial Doppler (TCD): A TCD is a type of ultrasound that determines whether the patient has atherosclerosis or narrowing of the blood vessels inside the brain. A TCD can also be used to find any blood clots in a patient’s blood vessels.
As the stroke is caused by a blood clot that moves into the brain, one common treatment is clot-dissolving medication. These can be administered orally or through an intravenous and are sometimes injected through a catheter. In some cases, surgery may be required to prevent additional strokes. This involves widening the arteries where there is a build-up of fatty deposits or plaque and is called a carotid endarterectomy. The surgeon may even install stents to keep the blood vessel from collapsing. Long-term treatment is often focused on regaining any motor or cognitive functions that were impaired by the stroke. Therapies include physiotherapy and speech therapy.
Prevention and recovery of an embolic stroke
The recovery period is different for every patient and is highly dependent on the severity of the stroke and which functions were affected. Younger patients often have a faster, fuller recovery than older ones. Patients with severe damage may never fully recover. Ongoing care for some period of time is required for most stroke patients.
In order to help prevent a stroke, the number one change to make is maintaining a healthy lifestyle. This includes maintaining a healthy weight, eating a diet rich in fruits and vegetables, exercising regularly, avoiding drinking to excess, and refraining from illegal drug use.
Embolic stroke and left atrial fibrosis
A recent study done comparing embolic stroke patients with a known cause for their stroke to embolic stroke of unknown source (ESUS) patients found that patients, where the cause of stroke is unknown, have higher variances of atrial fibrosis or abnormal heart rate than those with a known cause for their stroke. These findings suggest that atrial cardiomyopathy, which is impairment of cardiac function, may be related to ESUS.
An embolic stroke is a type of ischemic stroke, the most common of all strokes. It occurs when a blood clot travels to the brain, depriving the cells of oxygen and nutrients. Leading an unhealthy lifestyle is a major risk factor for developing a stroke and changing these habits is be the best way to prevent a stroke from occurring.
A stroke is considered a life-threatening medical emergency and medical attention should be sought immediately if any of the symptoms discussed above present themselves. The recovery from a stroke can be a long, arduous process, which is different for each patient and dependent on the severity of the damage done during the stroke.
Related: Ischemic stroke: Causes, symptoms, types, and treatment