Kidney biopsy prior to cyclophosphamide therapy in primary nephrotic syndrome.

The study includes 30 children, 10 each with minimal change nephropathy (MCNS), diffuse mesangial proliferative glomerulonephritis (MesPGN) and focal segmental glomerulosclerosis (FSGS). Indications for kidney biopsy were: steroid resistance in 12 cases, and frequent relapses on maintenance steroid therapy in 18 cases. A 2-year remission was achieved by cyclophosphamide therapy in 6 patients with FSGS, 8 patients with MCNS and 8 patients with MesPGN. In terms of initial response to corticosteroids, only 3 of 8 patients with early steroid resistance responded to cyclophosphamide therapy compared with 3 of 4 with late steroid resistance and 16 of 18 with frequent relapses on maintenance steroid therapy. Response to cyclophosphamide therapy correlates better with the initial corticosteroid response than renal histopathology. A kidney biopsy prior to administration of cyclophosphamide is not essential in patients who respond to initial corticosteroid therapy.