In nephrotic syndrome (NS) (synonyms: Acute nephrosis; Congenital nephrotic syndrome; Chromoprotein kidney [hemoglobinuric nephrosis]; Epstein nephrosis; Epstein syndrome; Glomerulonephritis with edema; Glomerulonephrosis; Hemoglobinuric nephrosis [chromoprotein kidney]; Hypocomplementemic nephrosis with glomerular lesion; Congenital nephrosis; Lipoid nephrosis; Nephritis desquamata; Nephritis with edema; Nephrosis; Nephrosis with glomerular lesion; Nephrosis syndrome; Nephrotic syndrome with dense-deposit disease; Nephrotic syndrome with diffuse endocapillary proliferative glomerulonephritis; Nephrotic syndrome with diffuse membranous glomerulonephritis; Nephrotic syndrome with diffuse mesangiocapillary glomerulonephritis; Nephrotic syndrome with diffuse mesangioproliferative glomerulonephritis; Nephrotic syndrome with focal glomerular lesion; Nephrotic syndrome with glomerulonephritis with diffuse crescent formation; Nephrotic syndrome with minimal glomerular lesion; Nephrotic syndrome with segmental glomerular lesion; Renal capsular edema; Renal cortical fatty degeneration; Paraprotein nephrosis; Protein nephrosis; Renal dropsy; Tubular parenchymatous nephrosis; ICD-10-GM N04. -: Nephrotic syndrome) is a symptom complex in which the following symptoms occur:
- Proteinuria > 3.0-3.5 g/day – excretion of protein with urine.
- Hypoproteinemia – decreased protein content in the blood.
- Hypalbuminemic edema – formation of water retention that occurs due to the decreased presence of certain proteins (albumin) in the body (when serum albumin < 2.5 g/day)
- Hyperlipidemia – increased blood lipids.
Furthermore, hypocalcemia (calcium deficiency) and accelerated ESR (erythrocyte sedimentation rate; inflammatory parameter) may be present. In childhood, nephrotic syndrome is defined as follows:
- Proteinuria > 1 g/m2KOF/day and.
- Hypoalbuminemia < 2.5 g/dL
Nephrotic syndrome occurs when there is damage to the glomeruli (renal corpuscles) in various diseases. Etiologically (causally) distinguish primary from secondary glomerular diseases.
There are hereditary cases of NS, especially with age of manifestation in the first 3 months of life (congenital NS) and in the 4th to 12th month of life (infantile NS).
Sex ratio: boys to girls equals approximately 2:1.
Peak incidence: idiopathic (without an identifiable cause) nephrotic syndrome in children occurs predominantly between the ages of 2 and 5 years.
The incidence (frequency of new cases) for idiopathic nephrotic syndrome in children is approximately 2-5 cases per 100,000 children per year (in Germany). The incidence for nephrotic syndrome is 3-7 diseases per 100,000 population per year (in Germany).
Course and prognosis: If left untreated, the disease leads to renal insufficiency (kidney weakness) (90% of cases). Therefore, an early therapy is very important. A possible complication is thrombosis due to hypoproteinemia and the associated decrease in the coagulation factor antithrombin III. The tendency to thrombosis is 50%. Nephrotic syndrome occurs recurrently (recurring) in 80-90% of patients. In children, the following rule of thumb applies: one-third do not get recurrences, one-third have infrequent recurrences (“infrequent relapsers”), and one-third have frequent recurrences (“frequent relapsers”) or subsequent steroid-resistant nephrotic syndrome (SRNS; up to 15%)). Note: With increasing duration of therapy, there is a risk of steroid toxicity!
