[Management of idiopathic nephrotic syndrome in childhood]

The management of idiopathic nephrotic syndrome (INS) in children includes immunosuppressive and symptomatic treatment. The response to corticosteroid therapy is the best prognostic marker of the disease. The majority of children with INS (about 85%) are steroid-sensitive as they normalize proteinuria within 4 weeks of daily, oral prednisone administration. The most of steroid-sensitive patients (94%) has minimal change of nephrotic syndrome, while the majority (80.5%-94.4%) of those who are steroid-resistant has focal segmental glomerulosclerosis or mesangioproliferative glomerulonephritis. Initial therapy of INS consists of 60 mg/m2/day prednisone daily for 4 weeks followed by 40 mg/m2 on alternate days for 4 weeks, thereafter decreasing alternate day therapy every month by 25% over the next 4 months. Thus, the overall duration of the initial corticosteroids course is 6 months that may be significantly protective against the future development of frequent relapses. Approximately 30% of patients experience only one attack and are cured after the first course of therapy; 10-20% have only 3 or 4 steroid-responsive episodes before permanent cure; the remaining 40-50% of patients are frequent relapsers, or steroid-dependent. Standard relapse therapy consists of 60 mg/m2/ day prednisone until urine is protein free for at least 3 days, followed by 40 mg/m2 on alternate days for 4 weeks. The treatment of frequent-relapses and steroid-dependent INS includes several different regimens: maintenance (6 months) alternate steroid therapy just above steroid threshold (0.1-0.5 mg/kg/48h), levamisole, alkylating agents (cyclophosphamide or chlorambucil) or cyclosporine. The worse prognosis is expected in steroid-resistant patients who are the most difficult to treat. Renal biopsy should be performed in them. At present, there is no consensus on therapeutic regimen for steroid-resistant patients. The following immunosuppressive drugs have been used with varying success: cyclosporine, intravenous methyl prednisone pulses alone or combined with or followed by alkylating agents, plasma-exchange, and angiotensin-converting enzyme (ACE) inhibitors. Symptomatic treatment includes: 1) dietary regimen with normal protein intake and salt restriction, 2) calcium and vitamin D are prescribed with steroids, 3) diuretics should be used in case of severe edema, 4) infusion of albumin in case of severe hypovolemia, 5) treatment of hypertension, 6) anticoagulant therapy, and 7) prophylactic antibiotics in high-risk patients.