Histopathologic Diagnosis and Outcome of Renal Biopsied Pediatric Nephrotic Syndrome

ABSTRACT

PURPOSE: To determine the histological findings and treatment outcome in cases of childhood nephrotic syndrome which required renal biopsy. METHODS: We retrospectively reviewed the clinical, laboratory, pathologic findings and therapeutic outcomes of 169 nephrotic children who received a renal biopsy at the Department of Pediatrics, Kyunghee Medical University Hospital, Seoul from 1984 to 2004 over a period of 21 years. The renal biopsy was performed in nephrotic children who showed atypical features at presentation, or needed cytotoxic therapy because of frequent-relapsing, steroid-dependent, or steroid-resistant nephrotic syndrome(SRNS). RESULTS: Minimal change disease(MCD) was found in 52.1% of the patients, followed by diffuse mesangial proliferation(33.1%), focal segmental gomerulosclerosis(5.3%), membranoproliferative glomerulonephritis(2.4%), membranous nephropathy(2.4%), and IgA nephropathy(1.8 %). In MCD children, 14.8% had hematuria, 22.7% had hypertension, 5.7% showed decreased renal function, and no patient was found to have an abnormal complement level. Among patients diagnosed with diseases other than MCD, 43.2% had hematuria, 21.0% was found to be hypertensive, 7.4% of children showed decreased renal function and only 3(3.7%) had decreased complement level; the rates of hematuria and SRNS were found to be significantly higher than MCD patients. Among 37 SRNS patients, 30(81.0%) showed a final remission state with long-term steroid therapy, including methylprednisolone pulse therapy, over 4 months, with or without cytotoxic therapy. CONCLUSION: Almost half of the cases of childhood nephrotic syndrome requiring renal biopsy were not diagnosed with MCD. Among atypical features, hematuria and steroid-resistance would be the most probable indicators for a diagnosis other than MCD. Even in patients with SRNS, long-term methylprednisolone pulse therapy may result in a good remission rate.