Nephrotic Syndrome (NS)

Nephrotic syndrome (NS)

A nonspecific clinical and laboratory symptom complex, including massive proteinuria (3.5 g/day or more), hypoalbuminemia (protein less than 30 g/l), hypoproteinemia and edema, reaching the degree of anasarca with hydrops of the serous cavities. Hypercholesterolemia is often (but not always) observed. The term "nephrotic syndrome" is widely used in WHO classifications of diseases and has almost replaced the older term "nephrosis".

NS can be primary or secondary. Primary NS develops with kidney diseases themselves (all morphological types of glomerulonephritis, renal amyloidosis). Secondary NS is less common, although the group of diseases that cause it is very numerous: systemic diseases (systemic lupus erythematosus, hemorrhagic vasculitis, infective endocarditis, polyarteritis nodosa, systemic scleroderma), thrombosis of the veins and arteries of the kidneys, aorta or inferior vena cava, diabetic glomerulosclerosis, nephropathy of pregnancy , kidney cancer, lung cancer, lymphogranulomatosis (paraneoplastic NS), allergic diseases, etc.

The pathogenesis of NS is closely related to the underlying disease. Most of the diseases listed above have an immunological basis, that is, they arise due to the deposition in the organs (and kidney) of complement fractions, immune complexes or antibodies against the glomerular basement membrane antigen with concomitant disorders of cellular immunity. The main link in the pathogenesis of the leading symptom of NS - massive proteinuria - is the decrease or disappearance of the constant electrical charge of the wall of the capillary loop of the glomerulus. All other numerous disorders in NS are secondary to massive proteinuria.

As a result of hypoproteinemia, sodium retention and systemic impairment of vascular permeability, edema develops.

Symptoms, course. The clinical picture of NS, in addition to edema, dystrophic changes in the skin and mucous membranes, can be complicated by peripheral phlebothrombosis, bacterial, viral, fungal infections of various localizations, edema of the brain, retina, nephrotic crisis (hypovolemic shock).

In some cases, signs of NS are combined with arterial hypertension (mixed form of NS).

Diagnosis of NS is not difficult. The diagnosis of the underlying disease and nephropathy causing NS is made on the basis of anamnestic data, clinical examination data and data obtained using a puncture biopsy of the kidney (less often of other organs), as well as additional laboratory methods (LE cells for systemic lupus erythematosus).

The course of NS depends on the form of nephropathy and the nature of the underlying disease. In general, NS is a potentially reversible condition. Thus, the nephrotic form of chronic glomerulonephritis (even in adults) is characterized by spontaneous and drug-induced remissions, although there may be relapses of NS (up to 5-10 times over 10-20 years).

With radical elimination of the antigen (timely surgery for the tumor, exclusion of the antigen drug), complete and stable remission of NS is possible. Persistent course of NS occurs in membranous, mesangioproliferative glomerulonephritis. The progressive nature of the course of NS with the outcome in chronic renal failure in the first 1.5-3 years of the disease is observed with rapidly progressing nephritis.

Treatment of patients with NS consists of diet therapy - limiting sodium intake and animal protein intake to 100 g/day. Inpatient treatment without strict adherence to bed rest and physical therapy to prevent thrombosis of the veins of the extremities. Sanitation of foci of latent infection is mandatory.

Pathogenetic treatment of NS: 1) glucocorticoids; 2) cytostatics; 3) anticoagulants, antiplatelet agents; 4) anti-inflammatory drugs. To reduce edema, diuretics are used; to correct hypovolemia, it is advisable to administer albumin or rheopolyglucin intravenously. The effectiveness of therapy is determined by the nature