Regardless of the possible underlying causes, in principle a stroke results from a mismatch between blood or oxygen supply and demand. The brain is very active, making it very sensitive to a lack of oxygen. Brain tissue is destroyed after only a few minutes. Then corresponding, often irreparable, deficits occur.
Stroke: common causes
Clearly the most common cause is sudden circulatory disturbances – predominantly caused by reduced blood flow in brain vessels that are too narrow, but also as a result of bleeding into the tissue. Other causes of stroke are injuries, brain inflammation or tumors.
The cause of acute reduced blood flow is – similar to a heart attack – usually a vessel occlusion as a result of arteriosclerosis that has progressed over many years. This is also called ischemic cerebral infarction. Deposits on the inner walls of the vessels cause them to become narrower and narrower, less and less blood reaches the brain areas, and the blood flows more slowly. Therefore, blood clots are more likely to form, which then completely occlude the vessel (thrombosis), or small particles are released from the deposits, which are washed away with the bloodstream and also lead to occlusion (embolism).
Risk factors for stroke
In addition, in such pre-damaged vessels, drops in blood pressure also lead to supply difficulties, since not enough blood can pass through our narrow vascular streets. In about 15-20% of all cases, the sudden rupture of a vessel leads to hemorrhage and consequently to tissue breakdown along with its symptoms. This form of stroke is called intracerebral mass hemorrhage.
The risk of stroke is increased by all factors that also promote arteriosclerosis: above all high blood pressure, but also elevated blood fat levels, diabetes, smoking, high alcohol consumption, obesity, lack of exercise and taking birth control pills. Atrial fibrillation is also a known risk factor. In addition, hereditary susceptibility also plays a role – the only factor besides age that cannot be influenced.
