Causes of Stroke
The main cause of a stroke is a disruption of the blood flow to some part of the brain due to arterial occlusion or rupture of the cerebral artery.
Arterial occlusion causes are:
- Embolism – when a blood clot breaks away from it place of origin and gets into the arteries of the brain (usually in the carotid artery);
- Thrombosis – formation of a blood clot occurs in cerebral vessels, usually as a result of Atherosclerosis. If Thrombosis develops in the blood vessel that supplies the brain, it leads to brain tissue swelling (edema).
The causes of a cerebral artery rupture:
- High Blood Pressure (Arterial hypertension);
- Congenitally weak arterial walls, for example, aneurysm;
- Severe injury (e.g. hard blow to the head as a result of an automobile accident);
Stroke risk factors can be divided into:
- High Blood Pressure – blood pressure that is higher than 140/90 mmHg is often a major risk factor for a stroke. When blood constantly presses too hard on the walls of the arteries, it may weaken them and, eventually, lead to a stroke;
- Smoking – nicotine constricts blood vessels and causes spasms, and the carcinogenic substances contained in tobacco promote the accumulation of cholesterol on the walls of the vessels as well as the formation of blood clots;
- Stress – permanent rush of adrenaline and stress hormones exhausts the nervous system and causes an increase in a heartbeat and blood pressure. This changes the structure of the vessels, increases blood coagulation and leads to thrombosis;
- Excess Alcohol Consumption – increases blood pressure and provokes chronic hypertension, which automatically puts you at risk;
- Atrial Fibrillation and other cardiovascular disorders – atrial fibrillation is characterized irregular heartbeats. It raises the risk of having a stroke by five times. In cases of atrial fibrillation, both upper chambers of the heart contract rapidly and unpredictably, which creates the conditions for the blood to pool in the heart and may cause the formation of thrombus. The blood clots may be carried to the brain with the blood flow and cause ischemic stroke;
- Overweight – excess weight make hearts work harder to deliver blood to all the tissues and organs of the body. Blood vessels may fail to cope with such strain and react by increasing blood pressure;
- Increased Blood Cholesterol – high levels of 'bad' cholesterol in the blood lead to the development of Atherosclerosis (the formation of atherosclerotic plaques). It may result in thrombosis, constriction or occlusion of the vessels, and consequently causes stroke;
- Lack of Exercise – sedentary lifestyle makes our vessels 'lazy' and brain cells suffer from the lack of oxygen;
- Diabetes – the increase in the level of blood sugar leads to the increased amounts of fat deposits being accumulated in blood vessels. The more there are fat deposits in the vessels, the higher is the risk of arterial occlusion or stroke;
- Previous Transient Ischemic Attacks (Stroke) – after the first stroke the risk of having another one increases by 10 times;
- Use of oral contraceptives – the drugs that contain over 50mg of estrogen are proven to increase the risk of cerebral infarction. The combination of their use and smoking or high blood pressure is particularly unfavorable;
- Age – the risk of developing a stroke rises with age. One third of those who have faced a stroke are people aged from 20 to 60 years. Two thirds of all strokes develop in people over 60. Every decade after the age of 55 doubles the risk of stroke;
- Family history – people whose close relatives had a stroke are at a higher risk of developing this condition;
- Gender – stroke is more common in males; however, females die from stroke attacks more often than males.
Next chapter: Symptoms of Stroke
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