Stroke as a result of an infarction (alchemic stroke)
Most strokes (85%) are caused by an infarction in the brain’s blood vessels. The most common cause of an infarction in blood vessels is arteriosclerosis. Another cause is a blood clot or other substance released from an artery wall outside of the brain or heart, carried to the brain and blocking vital blood vessels. This phenomenon is called an embolism. When the blood clot settles in the blood vessel and blocks the passage of oxygen to the brain, damaging brain tissue and a cerebral infarction occurs.
Stroke due to a hemorrhage
A. Cerebral hemorrhage resulting from aneurysm leakage. An aneurysm is a balloon-like bulge or pocket in the arterial wall that becomes thin and stretched. When an aneurysm is torn, a hemorrhage between the brain and its membranes known as a subarachnoid hemorrhage occurs.
B. Cerebral hemorrhage. When a blood vessel bursts inside brain tissue and blood leaks into the tissue, which damages it and leads to cell death. Additionally, nerve cells around the hemorrhage area are not provided with normal blood supply and are damaged too.The most common cause of brain hemorrhage is hypertension.
Sometimes aneurysms can be identified before a hemorrhage occurs. A sudden, unexplained headache can be a sign of a hemorrhagic stroke.
Stroke risk factors
The most important risk factor of a stroke (70% of those suffering from a stroke have hypertension). Hypertension has no symptoms, and can only be identified by measuring blood pressure by the doctor or at home. The higher the blood pressure – the higher the risk to suffer a stroke, and the opposite is also true: a reduction of 6 mm mercury in the value of diastolic blood pressure leads to as much as 40% reduction in the risk to suffer a stroke. Regular measurement of blood pressure values and strictly balancing it (especially in those with obesity, diabetes, alcohol consumption, no physical activity or familial tendency to hypertension) are critical to the prevention of strokes. The recommended blood pressure is 70-130/80-120
Strokes are 4 times more common in diabetes patients (whether type 1 or 2) compared to the general population. This disease can begin with no significant symptoms, but can be identified by a simple blood test at the HMO. Unbalanced diabetes can lead to blockage of small blood vessels in various body parts such as the intestines and kidneys, as well as to blockage of the brain’s blood vessels resulting in a stroke.
High blood fat levels
It is particularly important to maintain low levels of “bad cholesterol” (LDL) and high levels of “good cholesterol” (HDL). It is important to ensure the total blood cholesterol level does not exceed 190 mg per deciliter. The recommended LDL limit is 100 mg / dl for healthy people, less than that for those with risk factors, and less than 70 mg / dl for those who have had a catheterization, heart attack or stroke.
Arrhythmias (Atrial fibrillation)
Atrial fibrillation is the most common arrhythmia, and its frequency increases with age. It usually develops in patients suffering from other heart conditions (such as heart failure,heart valve disease or coronary atherosclerosis). The arrhythmia slows down blood flow between the atriums and ventricles. Blood that flows abnormally tends to coagulate and cause blood clots that can be carried with the blood to the brain causing an embolic stroke.Patients suffering from artial fibrillation have 5-6 times higher risk of experiencing a stroke compared to those with a normal heart rate. The fibrillation can be diagnosed with various non-invasive tests such as EKG. Treating arrhythmia and the use of anticoagulants can reduce the risk of a stroke by 70%.
Smoking is a catalyst for the development of arteriosclerosis and for increased levels of coagulation factors in the blood. It also advances the damage caused to the blood vessel walls in the brain.
Excessive alcohol consumption
Excessive drinking is a risk factor of an ischemic stroke as well as cerebral hemorrhage, but consuming alcohol – particularly red wine – in small amounts can protect against an ischemic stroke.
The risk to suffer a stroke is increased in obese people. The highest risk is experienced by those who tend to be overweight in the center of their bodies, known as “abdominal obesity”. Medical research has discovered that some of the risk factors are interrelated: obesity leads to high levels of blood fat, hypertension and insulin resistance – leading to the development of adult (type 2) diabetes. These phenomena are known as “metabolic syndrome”.
On the other hand, losing only 5% to 10% of one’s body weight can lead to 30% reduction in abdominal fat, resulting in significant improvement in the person’s risk profile as to suffering from cardiovascular disease.