Nephrotic Syndrome: Classification and Evaluation

Abstract

Nephrotic syndrome is defined by massive proteinuria, hypoalbuminemia, edema, and hyperlipidemia. Proteinuria is secondary to a defect of the glomerular filtration barrier. The main complications of nephrotic syndrome are infections and thromboembolic events. Although nephrotic syndrome may be secondary to many renal diseases, idiopathic nephrotic syndrome is the most frequent cause in childhood with a complete remission following corticosteroid therapy in 90% of cases. Less frequently, nephrotic syndrome is due to a primary or secondary glomerulonephritis or to a genetic defect of podocyte or glomerular basement membrane proteins. Genetic testing is proposed in children with steroid-resistant idiopathic nephrotic syndrome, children less than 1 year, children with familial history of proteinuria, or those with extrarenal symptoms. Kidney biopsy is performed in children older than 12 years and children who do not respond to steroid therapy.