Stroke occurs when the blood supply to the brain gets cut off. The most common type of stroke is ischemic stroke, when the blood supply to the brain is disrupted by a clot. Ischemic strokes are of two types, thrombotic stroke (clot is formed in the arteries of the brain) and embolic stroke (clot is formed outside the brain). Embolic stroke is a type of ischemic stroke, in which the clot is formed elsewhere in the body and travels through the blood stream, to the arteries of the brain.
Embolic stroke results from an embolus or a clot, which has travelled from another location. While the embolus can form in many areas in the body, heart, neck and chest are the commonest locations. The embolus enters the bloodstream and flows through it to reach the brain and neck arteries. It continues to travel till it gets lodged in one of the arteries supplying the brain. This results in blocking of the artery and the blood flow to the brain get affected, resulting in an embolic stroke.
Ischemic strokes account for around 80% of strokes in the United States. Embolic stroke occurs due to blocking of blood supply to the brain by an embolus, thus stopping the blood reaching the brain. This can result in death of brain cells due to lack of blood supply. Depending on the time for which the blood supply to the brain is stopped and the time in which the person receives emergency treatment, the severity and the damage caused can be assessed. Many deaths are caused due to embolic stroke every year, while many who survive, may be left with permanent disability.
Causes of Embolic Stroke
Causes of an embolic stroke include those that can form a clot in the brain, neck or heart. An embolus can result from deposition of atherosclerotic plaque on the inner lining of arteries. Embolus can also develop as a result of fat globules or air bubbles entering into the blood stream or getting lodged in arteries. Another cause of embolus formation is abnormal rhythm of the heart, medically termed as atrial fibrillation.
Some risk factors that can increase the risk of ischemic or embolic stroke include existing older age, heart disease, high blood pressure, high cholesterol, diabetes, obesity, certain autoimmune disorders and a family history of stroke or heart disease. Lifestyle preferences like smoking, alcohol consumption, faulty dietary habits too can increase the risk of embolic stroke.
Symptoms of Embolic Stroke
Embolic stroke presents itself with the warning signs of stroke, which, if identified in the early stages can help in initiation of immediate medical treatment. The precise symptoms may vary depending on which part of the brain is affected during the embolic stroke.
The signs and symptoms of embolic stroke include:
- Sudden changes in the face, numbness in one part of the face, inability to smile or drooping of lips to one side.
- Weakness or numbness in arms, legs or one side of the body, appearing suddenly can be a symptom of Embolic Stroke.
- Sudden difficulty in seeing objects with one or both eyes,
- Severe headache, confusion, difficulty in understanding or trouble speaking.
- Sudden loss of balance, difficulty in co-ordination, dizziness or trouble in walking can be a symptom of Embolic Stroke.
Diagnosis of Embolic Stroke
Embolic stroke is an emergency situation, which needs immediate medical care. History and clinical examination can reveal existing medical problems and the symptoms of embolic stroke, if experienced any. The degree of severity can be assessed and emergency medical management approach can be planned.
Investigations like scanning of the brain, angiogram or Doppler studies may be performed to gauge the formation of clots and blood flow to the brain. Investigations of the heat may also be done to evaluate the heart functioning, presence of any blood clots and related problems that may have caused an embolic stroke.
Treatment of Embolic Stroke
Embolic stroke calls for an emergency treatment plan, aimed at dissolving the clot or removing the embolus from the artery and restoring the blood supply to the brain. Medicines to remove the clot are given orally or administered intravenously.
Surgical procedures that help to prevent further episodes of stroke may be required. These include, opening the narrowed arteries that have plaque deposition inside (carotid endarterectomy) or stents may be placed in the artery to keep it open and prevent from narrowing. Long term treatment depends on the cause of embolic stroke and often includes medications to prevent further attacks of stroke.
Recovery Period for Embolic Stroke
Recovery depends on the degree of damage caused during the embolic stroke. In most cases, difficulty in movement of limbs may persist after the episode and may recover within few months. Physical or speech therapy and rehabilitation is often required to regain the strength, co-ordination, balance, speech ability and other impaired functions.
Most patients show steady improvement with proper rehabilitation and regular medication. Persons with fewer and milder symptoms often have better recovery than those with major symptoms of greater severity. Similarly, younger persons may show improvement better than older ones.