• Nephrology: Clinic and Symptoms of Kidney Amyloidosis

    In most cases, renal pathology is manifested not only by local signs of their defeat. Since their value for the whole organism is invaluable. Therefore, the symptoms of kidney amyloidosis include a number of disorders from other organs.

    Short anatomical and physiological characteristics of the kidneys

    Kidneys are the central organs of the urinary system. These paired organs are located in the retroperitoneal space in the region of the two lower thoracic vertebrae and the upper lumbar vertebrae. The left is slightly higher than the right, because its upper edge does not experience liver pressure.

    The size of the kidneys is approximately the same. Their length does not exceed 10-12 centimeters.4-6 cm - width, thickness - 2-3 cm

    The main role of the kidneys is to remove toxic metabolic products for the body. To do this, they are well sucked through the renal arteries - the largest blood vessels in the body. This ensures the passage through their glomeruli of a large amount of blood per unit time. Through the vessels of the kidney passes about 1 liter of blood in 60 seconds. This is 1,5 thousand liters in 24 hours.

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    Mechanisms of development of amyloidosis

    This is important! Amyloid - a pathological protein( protein), formed from compounds of amino acids of its own origin. The leading link in its formation is the disturbance at the stages of protein biosynthesis in some cells. Basically, these are tissue macrophages, a class of immune cells that are constantly found in a particular organ and tissue.

    At the molecular level, this is simplified( since the exact mechanisms have not yet been proved) can be represented as follows. Amino acids during the synthesis of protein complexes are combined with some foreign substances. As a result, on the "output" and turns out pathological protein. It differs from normal protein by the absence of specific functions and deviations in the set of genes histocompatibility. These special markers are available for any large molecule and body cells. This is a kind of "passport", according to which immunity is distinguished by alien inclusions and organisms.

    Once pathological proteins are synthesized, they enter the bloodstream, where they are immediately recognized by the defense system. It starts producing antibodies against these proteins. When antibodies interact with amyloid( in this case it is an antigen), its insoluble components begin to settle on the endothelium( inner shell) of the vessels. However, they do not carry any functional load. Simply put, they are a "dead weight" in the tissues. Gradually, the amyloid displaces the functioning elements of the organ, reducing its productivity and leading, ultimately, to death.

    In relation to the kidneys, amyloid is deposited on the basement membrane. That reduces their filtration functions. Therefore, the first symptoms of kidney amyloidosis begin precisely with a decrease in excretion from the body.

    Causes of development of amyloidosis

    In the development of amyloidosis, disturbances at the molecular level play an important role. And they are known to be influenced by many factors. In this connection, all the causes of amyloidosis can be classified into genetic, non-genetic and idiopathic or unknown.

    1. Genetic causes. It is assumed that glitches in the synthesis of proteins can be caused by genetic anomalies of cells. This is clearly seen from observations. So, for some sufficiently closed ethnoses, the so-called accumulation diseases are characteristic. Moreover, these reasons can have both hereditary and non-hereditary character. For example, a periodic illness in the Armenians or a Mediterranean fever in the Portuguese. Another variant of genetic amyloidosis is multiple myeloma or myeloma.
    2. Non-genetic causes. Are, perhaps, the largest group of reasons:
      • Chronic infectious diseases. Their direct connection with the development of the disease is not proven. But observations indicate that in such patients amyloidosis occurs many times more often. Such pathologies include: tuberculosis, syphilis, malaria, bacterial endocarditis.
      • Chronic non-infectious diseases. Autoimmune rheumatoid arthritis, psoriasis, Bechterew's disease, ulcerative colitis, Crohn's disease and some others. For them, too, direct influence on the formation of pathological proteins has not been proven. But with these nosologies, the incidence of amyloidosis is high.
      • Endocrine pathology. Among them, amyloidosis is most common in patients with diabetes mellitus.
      • Hemodialysis. The only condition is the occurrence of amyloidosis at which is reliably proven.
    3. Idiopathic causes. These include most genetic anomalies with questionable evidence of the role of chromosome mutations in the development of amyloid. But traditionally this group includes primary amyloidosis of the kidneys and other organs. The reasons for its appearance absolutely do not fit into the two previous categories.

    Clinic of amyloidosis of the kidneys

    It is common to distinguish several stages for kidney damage when depositing a pathological protein. They differ both in the characteristics of the clinic and in the course of the disease itself:

    1. The initial stage or stage of minimal changes. Here the symptoms of amyloidosis of the kidneys are practically not found, since the degree of damage to the glomeruli is minimal in view of the small amount of pathological protein. But the manifestations of the underlying disease are clearly visible, in the case of secondary amyloidosis. With idiopathic pathology, the clinic is absent completely glad for a number of years. Usually this period does not exceed 3-5 years. All envy of the state of the body, external environmental factors and the presence of concomitant diseases.
    2. Stage of proteinuria. At first, the symptomatology of the disease is absent, but its diagnosis is possible. A simple urine test is sufficient, which clearly shows the excess of proteinuria( protein in the urine) by several orders of magnitude. Then, as protein is lost through the kidneys, the first signs of their defeat appear - edema. They are localized on the upper half of the body and unlike the cardiac pathology are soft and warm to the touch. But they are temporary and not regular. In most cases, people associate their appearance with excessive consumption of food. Nephrotic or edematous stage. Proteinuria reaches a significant extent. The swelling becomes permanent and spreads not only to the lower eyelids of the eyes, but also to the arms of the trunk. There is an increase in blood pressure, an increase in the liver and spleen. Among the analyzes striking in the eyes expressed gipoproteinemi( decrease in the amount of protein in the blood), hypercholesterolemia( increase in cholesterol in the blood) and proteinuria. At the same time, nitrogen exchange rates are slightly higher than normal. Dizziness and syncope, arrhythmias, and a decrease in appetite may occur at this stage.
    3. Terminal stage. He talks about complete disorganization of the kidneys. In addition to proteinuria, hypercholesterolemia and hypoproteinemia, there is a significant content of urea, uric acid and creatinine in the blood. The amount of residual nitrogen in the blood also reaches the same high values. All these are signs of increasing renal failure.

    All treatment of kidney amyloidosis depends on two factors. This is the cause of the disease and the stage of the disease. In general, substances that suppress the activity of immunity are used. Such as prednisolone, polcortolone, dexamethasone, cytostatics. When complications develop, symptomatic drugs are used.

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