Nephrotic syndrome in children

Nephrotic syndrome is a symptom complex that includes pronounced proteinuria (more than 3 g/l), hypoproteinemia, hypoalbuminemia and dysproteinemia, pronounced and widespread edema (peripheral, cystic, anasarca), hyperlipidemia and lipiduria.

Nephrotic syndrome in children is divided into primary, associated with a primary disease of the glomeruli of the kidneys, and secondary, caused by a large group of congenital hereditary and acquired diseases.

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Pathogenesis of nephrotic syndrome

In the occurrence of water-electrolyte disturbances, development of edemas in nephrotic syndrome, the renin-angiotensin-aldosterone system, antidiuretic and natriuretic hormones, kallikrein-kinin and prostaglandin systems are of importance. The loss of many proteins with urine leads to changes in coagulation and fibrinolysis. In nephrotic syndrome, a deficiency of anticoagulants (antithrombin III - plasma cofactor of heparin) is established; disturbances in the fibrinolytic system - the content of fibrinogen increases. All this contributes to hypercoagulation and thrombus formation. Thrombosis of the renal veins is especially dangerous. Thus, nephrotic syndrome is accompanied by a number of changes in homeostasis.

Atrial natriuretic peptide (ANP) also plays a role in the genesis of nephrotic edema. Disruption of the normal effect of ANP on transport processes in the collecting ducts of the renal tubules is accompanied by a decrease in natriuresis and accumulation of intravascular fluid, which contributes to the formation of nephrotic edema. Thus, nephrotic syndrome is accompanied by a number of changes in homeostasis.

In nephrotic syndrome, membranous and membranous-proliferative glomerulonephritis are most often observed, less often focal segmental glomerulosclerosis.

Primary nephrotic syndrome:

• Congenital and infantile:
  • congenital "Finnish type" with microcystic disease;
  • "French type" with diffuse mesangial changes;
  • minimal change nephrotic syndrome;
  • nephrotic syndrome with mesangioproliferative changes or with focal segmental glomerulosclerosis.
• Nephrotic syndrome in primary glomerulonephritis:
  • Minimal change nephrotic syndrome;
  • Nephrotic syndrome with membranous changes or focal segmental glomerulosclerosis; membranous-proliferative, mesangioproliferative, extracapillary with crescents, fibroplastic (sclerosing) changes.

Nephrotic syndrome secondary, in hereditary, congenital and acquired diseases:

• diffuse connective tissue diseases (systemic lupus erythematosus);
• systemic vasculitis;
• infectious diseases (tuberculosis, syphilis, hepatitis, malaria);
• diabetes mellitus;
• reactions to medications (antiepileptic drugs, gold, bismuth, mercury preparations, antibiotics, vitamins);
• renal vein thrombosis.

Nephrotic syndrome can manifest itself as a complete and incomplete, pure and mixed (with hematuria and arterial hypertension) symptom complex.

Primary nephrotic syndrome includes congenital and nephrotic syndrome in primary glomerulonephritis.

Morphological variants of primary nephrotic syndrome in glomerulonephritis: minimal changes, membranous, focal-segmental, mesangiocapillary (membranous-proliferative), extracapillary with crescents, fibroplastic.

In the structure of primary nephrotic syndrome in children aged 1-7 years, glomerulonephritis with minimal changes, the so-called lipoid nephrosis, predominates (more than 85-90%).

In children aged 12-16 years, the structure of primary glomerulonephritis is dominated by membranous-proliferative glomerulonephritis (all 3 types), which is most often manifested by mixed nephrotic syndrome with hematuria and/or arterial hypertension, which has a serious prognosis.

Nephrotic syndrome

Nephrotic syndrome is one of the most pronounced and characteristic manifestations of acute and chronic kidney diseases in children. The presence of nephrotic syndrome always indicates damage to the kidneys - primary or as part of other diseases. The appearance of nephrotic syndrome in kidney diseases indicates increased activity of the renal process.

Symptoms of nephrotic syndrome

Edema is characteristic - first of the face, eyelids, then in the lumbar region, legs. Paleness of the skin. Oliguria associated with hypovolemia, hyperaldosteronism, damage to the tubules.

Secondary hyperaldosteronism is typical of nephrotic syndrome, resulting in sodium and therefore water retention in the body, although there is hyponatremia in the blood.

In children, hypovolemia often develops spontaneously, in the initial stage of nephrotic syndrome, when the rate of protein loss exceeds the rate of protein mobilization from extravascular depots and its synthesis by the liver.

Course of nephrotic syndrome

Often undulating, recurrent. Relapsing nephrotic syndrome is the occurrence of at least 2 relapses in 6 months; frequently relapsing course is 2 or more relapses in 6 months or 4 or more per year, when the relapse occurred within 2 months after the cessation of therapy. Complete remission is understood as the patient's condition when proteinuria is less than 4 mg/m2 ^/ hour or less than 10 mg/kg/hour, and the serum albumin level is equal to or more than 35 g/l. Partial remission means the elimination of edema, hypo- and dysproteinemia, a decrease in daily proteinuria to a level of less than 3.5 g/day or maintaining it within 5-40 mg/m2 ^/ hour and serum albumin is more than 30 g/l.

Treatment of nephrotic syndrome

Bed rest during the period of edema can lead to an increase in diuresis, since in a horizontal position the hydrostatic pressure on the lower extremities decreases, which facilitates the return of fluid from the interstitial space to the plasma. Access to fresh air.

Diet - salt-free for 2-3 weeks with subsequent gradual introduction of 0.5-1 g to 3 g per day. Hypochloride diet remains for many years. Proteins of high biological value 1 g / kg of body weight taking into account the daily loss of protein. Fat content providing less than 30% of the total caloric value of food with a high ratio of polyunsaturated / saturated fatty acids, linoleic acid content in an amount providing at least 10% of the total caloric value of food and low cholesterol.

It is recommended to use sea fish, shrimp, seaweed, which increase the fibrinolytic activity of the blood. Use of vegetable oil. It is advisable to include oats, rich in phospholipids, in the diet in the form of porridge, jelly, decoction. During the period of edema reduction, products containing potassium are introduced: baked potatoes, raisins, dried apricots, prunes, bananas, pumpkin, squash. Liquid is not limited. An elimination diet is prescribed to children with a burdened allergic anamnesis.

Drug treatment of nephrotic syndrome

With minimal changes, glucocorticoid therapy is prescribed. The initial dose of prednisolone is 2 mg/kg/day (no more than 60-80 mg) daily for 4 weeks. The maximum dose is reduced provided that there is no proteinuria in 3 consecutive urine tests. The dose is reduced by 2.5-5 mg every week. Then, intermittent therapy is carried out - 3 days in a row, a break of 4 days or every other day. The duration of the first course is from 2 months to 2 years (the maintenance dose is usually 10-15 mg/day). If the treatment is successful, prednisolone monotherapy remains. In case of frequently recurring NS, cytostatics are added to hormonal therapy - cyclophosphamide or methylprednisolone (pulse therapy for 3 days, 20 mg/kg per day intravenously, followed by prednisolone every other day for 6 months). In hormone-resistant nephrotic syndrome - lack of normalization of urine parameters and the onset of clinical and laboratory remission during treatment with glucocorticosteroids for 4-8 weeks - glucocorticosteroids and cyclophosphamide 1.5-2 mg/kg are prescribed for up to 16 weeks.

Indications for heparin in case of risk of thrombotic complications:

1. hypoalbuminemia below 20-15 g/l;
2. hyperfibrinogenemia above 5 g/l;
3. reduction of antithrombin III to 70%.

In case of hypoalbuminemia below 15 g/l, in order to prevent hypovolemic crisis, intravenous drip administration of rheopolyglucin followed by jet administration of lasix 1 mg/kg (or without it) is indicated.

In case of hypoalbuminemia below 15 g/l, in order to prevent thrombotic complications, the drugs of choice may be curantil at a dose of 3-4 mg/kg/day or ticlid 8 mg/kg/day. In order to correct hyperlipidemia and lipiduria, the food supplement eikonal is prescribed, as well as drugs that block the synthesis of cholesterol and low-density lipoproteins - lipostabil, lovastatin. In order to stabilize cell membranes, alpha-tocopherol, essentiale forte, dimephosphone are used. Calcium carbonate, calcium gluconate are used to prevent and treat osteopenia and osteoporosis. In case of acute respiratory viral infections - reaferon, interferon.

Outpatient observation is carried out by a pediatrician and a nephrologist until the child is transferred to an adult clinic. After discharge from the hospital, urine testing is carried out once every 2 weeks for the first 3 months, then once a month during the first year of observation, and once a quarter in the second year and subsequent years. At each visit to the doctor, blood pressure is measured, treatment is adjusted and observation is carried out. In case of intercurrent diseases, urine testing is mandatory during the illness and 10-14 days after its end, and an ENT doctor and dentist are consulted once every 6 months. Sanitation of chronic foci of infection is necessary.

The prognosis depends on the morphology of glomerulonephritis. With minimal changes - more favorable, with other forms the prognosis should be cautious, with focal segmental sclerosis - unfavorable, development of chronic renal failure.

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