Stroke and blood clots
Ischemic strokes happen when a blood clot (thrombus) or a fatty deposit blocks an artery supplying blood to the brain. Around 80% of all strokes are ischemic in origin. The remaining 20% of strokes are hemorrhagic, where an artery bursts. These can be caused by an aneurysm, a bulge or weakness in the wall of a blood vessel.
All of us have clotting factors in our blood to ensure we do not bleed to death if we cut ourselves. But conditions like hypertension, atherosclerosis and some other blood problems can lead to the development of blood clots. Thrombosis is the name given to the formation of blood clots. When the clot blocks the blood flow to the heart or the brain, a heart attack or stroke can follow. An embolism occurs when a blood clot travels around the body and lodges in an organ.
Symptoms of a blood clot
The symptoms of a blood clot depend on its location in the body.
In the brain the first symptom may be a stroke or a transient ischemic attack. The symptoms of these vary in degrees but include loss of vision in one field, facial weakness, speech impairment, difficulty understanding others, headache, loss of coordination.
In or around the heart, a blood clot causes a heart attack, the symptoms of which are severe chest pain that radiates into the left arm and shortness of breath. However, women may have more diffuse symptoms.
In the lung, a blood clot causes chest pain, elevated heart rate, blood on coughing, shortness of breath and low-grade fever.
In a limb, a blood clot will cause pain, swelling and discoloration of the affected area. If the clot is in a vein, swelling and tenderness will occur.
Predisposing conditions for thrombosis
Damage to the blood vessels: If the inner walls of a blood vessel (endothelium) are damaged, it makes it easier for blood clots to form. Damage to the endothelium exposes the underlying collagen in the blood vessel and this can promote clot formation.
Atherosclerosis is a common form of endothelial damage that can lead to thrombosis. Other kinds of endothelial damage can arise from physical injury, inflammation, hypertension, infection, radiation and smoking.
Turbulent blood flow causes endothelial injury. Turbulent blood flow occurs when blood vessels are affected by atherosclerosis, abnormal arterial dilations (aneurysms), and heart attack or heart valve damage.
You can inherit a propensity towards sticky blood or you may have a condition that makes you more prone to thrombosis like lupus, rheumatoid arthritis, certain cancers, pregnancy and vascular disease. People who have had surgery may also be at risk of blood clots. It is possible to treat the tendency to produce blood clots.
Lifestyle factors promoting blood clots
Smoking, being more than 10 kg overweight, physical inactivity, using the contraceptive pill, using estrogen as found in some hormone replacement therapies, and immobility, can all lead to the formation of blood clots.
Some ways to prevent blood clots include: keeping physically active, maintaining a normal weight and not smoking. It is also important to manage any known heart diseases. Some people will need to take anti-clotting medication daily or after surgery, like aspirin.
Treatment and management
If you are diagnosed as having a thrombus or are at risk of developing a blood clot the treatment will depend on where any clot is, its size and your health.
If your diagnosis results from a heart attack or stroke, any treatment you receive will be initially to dissolve any blood clot. After that, therapies to prevent you developing clots will be used.
If your blood clot is in a vein, there is a risk it can travel to one of your organs and cause an embolism, which can be fatal. Treatment is a combination of heat, painkilling medications, anti-clotting medication and elevation/bandaging of the affected area to reduce swelling. Occasionally, surgery may be required to remove the clot.
World Heart Federation President Salim Yusuf leads Hope-3 trials on the prevention of heart attacks and strokes.
Science and Research
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