Atherosclerosis
Atherosclerosis is one of the most urgent diseases of the 21st century and also one of the four most common diseases and causes of death.
In healthy people, blood flows freely through the arteries to all body parts supplying them with oxygen and various nutrients. Cholesterol, as well as lecithin, are the substances found in fats, they circulate all over the human body and are essential for its normal vital functions; and in healthy people cholesterol and lecithin are always in dynamic equilibrium. If there is an excess amount of cholesterol in blood, it is deposited on the inner surface of the vessels forming atherosclerotic plaques (masses consisting of mixture of fats (mainly cholesterol) and calcium). Later, connective tissue starts developing around such plaques on the vessel walls and lime deposits begin. Over time, the plaque becomes fragile, defects appear on its surface, and a formation of thrombus – a cluster of cells, mainly platelets (blood elements that take part in the cancelation process) and blood proteins, – starts in the place of the defect on the inner side of the vessel.
Thrombus makes artery even narrower. A fragment may come off and get carried along the vessel with the blood flow until the opening of the vessel becomes so narrow that the fragment cannot pass. This stops the blood supply of the corresponding organ or tissue which causes the development of necrosis (infarction). Depending on the thrombosis location there may develop renal, splenic, bowel or other types of infarction. When such thrombus gets stuck in one of the arteries supplying the heart with blood, it results in myocardial infarction. If atherosclerosis affects cerebral arteries, the risk of stroke increases.
The disease develops over several years, slowly but surely it occupies the vessels that are not affected yet. When the lumen of the artery is narrowed by more than ¾, a person begins experiencing the first signs of the lack of blood supply to an organ or tissue.
Classification
The disease progresses unevenly, and in most cases it affects the vessels of various body parts. Therefore, there are the following types of atherosclerosis:
- Cerebral atherosclerosis. It leads to the circulatory insufficiency of the brain and naturally to its impaired functioning. The main danger of this form of atherosclerosis is that it can cause ischemic stroke;
- Coronary atherosclerosis. It is the most common and dangerous form of atherosclerosis. Coronary arteries are the most vulnerable parts of the circulatory system. Cardiac muscle gets the blood through these arteries, therefore if atherosclerotic plaque is formed in the artery, it blocks the supply of oxygen to the heart which causes angina and myocardial infarction. The plaques that are formed in coronary vessels are prone to the formation of blood clots;
- Atherosclerosis of aorta. Aorta supplies almost all body systems and organs with blood and, thus, when any of its parts or branches thickens, it has the most negative influence on the whole body;
- Mesenteric artery atherosclerosis. Mesenteric arteries deliver blood to the gastrointestinal tract. This form of atherosclerosis is manifested in two ways: firstly, it causes the thrombosis of the arterial branches leading to the infarction (necrosis) of the intestinal and mesenteric wall; secondly, it is manifested as abdominal angina – an attack of colicky pain appearing right after meals;
- Renal artery atherosclerosis. In this case kidneys don’t have normal blood supply and that causes severe hypertension. Sclerotic deformation of the renal artery walls leads to renal failure and up to nephrosclerosis;
- Lower extremity atherosclerosis. This form of atherosclerosis causes insufficient amount of blood delivered to the lower limbs, and gradually the lower leg and foot muscles are atrophied, ulcers appear on the toes and between them. These ulcers are covered with purulent coating, and they are very difficult to treat.
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