In the event of a stroke (synonyms: stroke, insult, apoplexy), a circulatory disorder of blood vessels in the brain results in a reduced supply of blood and oxygen to downstream brain areas. Depending on its location, the circulatory disorder leads to various neurological deficits, such as hemiplegia or hemiplegia, weakness or even paralysis of an individual limb, weakness or paralysis of one half of the face, sensitivity disorders of one limb or the entire half of the body (for example, numbness), visual disorders or speech disorders. Typically, the complaints occur very suddenly.
In 80% of cases, a stroke is caused by an obstruction of a blood vessel, a so-called ischemia (ischemic stroke). In about 20% of cases, a cerebral haemorrhage is the cause of the circulatory disorder (haemorrhagic stroke). Since the affected brain area dies without the supply of blood and oxygen, the diagnosis must be made quickly and immediate therapy must be initiated. Depending on the genesis of the stroke, different therapeutic concepts can be considered.
A stroke causes a circulatory disorder in the brain and thus an undersupply of blood and oxygen to brain tissue. In over 80% of cases, the circulatory disorder is caused by an acute occlusion of a blood vessel. This is known as an ischemic stroke.
Often the reason for the occlusion of a blood vessel is a highly pronounced calcification (arteriosclerosis), in which so-called plaques massively constrict the lumen of a blood vessel. If these plaques tear open in the course of the disease, blood clots, so-called thrombi, can form and further constrict the blood vessel or even completely block it. If the thrombus has formed outside the brain and has been infiltrated into a brain vessel via the bloodstream, this is called an embolism.
Other rarer causes of cerebrovascular occlusion include inflammatory changes in the blood vessels of the brain, known as vasculitis. In about 20% of cases, the stroke is caused by a cerebral hemorrhage. A stroke due to a cerebral hemorrhage is called a hemorrhagic stroke.
The most common cause of a hemorrhagic stroke is arterial hypertension (high blood pressure), which in the long term leads to damage to the small vessels and makes them porous. One of the most common causes is the so-called aneurysm, a bulging of a blood vessel, the tearing of which causes massive bleeding into the brain. Furthermore, the intake of blood-thinning medications, such as Marcumar® from the anticoagulant group, can be the cause of a cerebral hemorrhage. In rare cases, congenital coagulation disorders, vascular malformations or brain tumors are the cause of a hemorrhagic stroke. Important risk factors for a stroke are, in addition to arterial hypertension, obesity (overweight), diabetes mellitus (increased blood sugar), stimulants such as nicotine and alcohol, stress and pre-existing conditions such as a heart attack or cardiac arrhythmia, especially atrial fibrillation.