Amyloidosis of the kidneys

Amyloidosis - in most cases, a systemic disease, which is based on changes that lead to extracellular deposition in amyloid tissues (a complex protein-polysaccharide complex), ultimately causing a violation of the functions of the organs. In some cases, the fibrillar protein of amyloid has a number of properties that bring it closer to immunoglobulins; in others, without having these properties, it has an antigenic agent with a serum protein, considered a precursor of amyloid. Amyloidosis of the kidneys is a manifestation of a common amyloidosis. The amyloid in this organ is usually deposited in the main membrane, between the endothelium of the renal glomeruli and arterioles and in the primary membrane of the renal tubules.

The etiology, pathogenesis of amyloidosis is unknown. Usually this condition is associated with the presence in the body of a chronic infection (tuberculosis, syphilis) or suppuration (osteomyelitis, pulmonary suppuration). This is the so-called secondary amyloidosis. Secondary amyloidosis is also quite common and with such diseases as rheumatoid arthritis, ulcerative colitis, some tumors, prolonged septic endocarditis. There are also primary amyloidosis, amyloidosis in myeloma and Waldenstrom disease, hereditary (familial), senile and local (tumor-like) amyloidosis. Of the hereditary variants in the USSR, amyloidosis is more common with a periodic illness, which can occur even without typical attacks of this disease in the anamnesis.

Although the pathogenesis and causes of primary lesion of certain organs (kidneys, intestines, skin, etc.) with different variants of amyloidosis remain not completely clear, there are still data that allow us to identify the links in the development of this complex disease. Conditions conducive to the emergence and development of amyloidosis include disproteinemia, reflecting the distorted protein-synthetic function of RES, and immunological changes, primarily relating to the cellular system of immunity (suppression of the T-system, changes in phagocytosis, etc.).

Symptoms and course of amyloidosis are diverse and depend on the location of amyloid deposits, the extent of their prevalence in the organs, the duration of the disease, the presence of complications. The clinical picture becomes unfolded with the defeat of the kidneys-the most frequent localization, as well as the intestines, heart, nervous system. Kidney damage is typical not only with the most common secondary form of amyloidosis, but also with primary, including hereditary amyloidosis.

Patients with amyloidosis of the kidneys do not make any complaints for a long time, and only the appearance of edema, their spread, the increase in general weakness, a sharp decrease in activity, the development of renal failure, hypertension, complications (for example, renal vein thrombosis with pain syndrome and anuria) Consult a doctor. Sometimes there is diarrhea.

The most important symptom of amyloidosis of the kidneys is proteinuria. It develops in all its forms, but is most characteristic of secondary amyloidosis. With urine, up to 40 grams of protein are released per day, the bulk of which are albumins. Prolonged loss of protein by the kidneys leads to hypoproteinemia (hypoalbuminemia) and the associated edematous syndrome. With amyloidosis edema becomes widespread and persists in the terminal stage of uremia. Dysproteinemia is also manifested by a significant increase in ESR and changes in sediment samples. With expressed amyloidosis hyperlipidemia occurs due to an increase in the content of cholesterol, P-lipoproteins, triglycerides in the blood. The combination of massive proteinuria, hypoproteinemia, hypercholesterolemia and edema (classic nephrotic syndrome) is characteristic of amyloidosis with primary renal involvement.

In urine, in addition to protein, cylinders, erythrocytes, leukocytes are found in the sediment.

Among other manifestations of amyloidosis, there are cardiovascular dysfunctions (primarily in the form of hypotension, rarely hypertension, various conduction disorders and heart rhythm, heart failure), as well as the gastrointestinal tract (suction-impaired syndrome). Often there is an increase in the liver and spleen, sometimes without obvious signs of a change in their function.

The appearance and progression of proteinuria, especially the emergence of a nephrotic syndrome or renal failure in the presence of clinical or anamnestic signs of the disease, at which amyloidosis may develop, are of paramount importance for the diagnosis. But amyloidosis should also be considered in the absence of an indication of such a disease, especially when the etiology of nephropathy remains unclear. The method of ensuring reliable diagnosis of amyloidosis is currently a biopsy of the organ: most reliable - the kidneys, but also the mucous membrane of the rectum, less often the gum tissue, skin, liver. Morphological confirmation is necessary in all cases when a careful study of the anamnesis, including family history, clinical manifestations and laboratory indicators make it possible to diagnose amyloidosis.

Treatment (specific) of amyloidosis has not been developed, which is due to the lack of definitive ideas about the etiology and pathogenesis of this disease. Recommendations for general regimen and nutrition in amyloidosis are the same as in chronic glomerulonephritis. For the prognosis, the activity of treatment of the disease, which led to the development of amyloidosis, is important. The patient with amyloidosis shows a long (1.5-2 years) intake of raw liver (100-120 g / day). In the initial stages of the process, preparations of the 4-amino-quinoline series (delagil 0.25 g once a day for a long time under the control of blood tests-lenokopenia) are prescribed. It is also necessary to control the ophthalmologist - it is possible to deposit derivatives of the drug in the refractive media of the eye. The question of the appropriateness of the use of corticosteroid and cytotoxic drugs has not been finally solved. Amyloidosis should be considered rather a contraindication to treatment with these drugs. The courses of administration of a 5% solution of unithiol at 5-10 ml of IM are applied (30-40 days). The possibility of using colchicine is discussed. The volume of symptomatic therapy is determined by the severity of certain clinical manifestations (diuretics with a significant edematous syndrome, hypotensive drugs in the presence of arterial hypertension, etc.). The possibility of using hemodialysis and kidney transplantation in the terminal stage of renal failure in amyloidosis is still being studied.