Clinicopathological correlations in nephrotic children with IgA nephropathy

Background. The prognostic significance of nephrotic syndrome (NS) in children with IgA nephropathy (IgAN) is unclear. Methods. NS was found in eight children with IgAN (mean onset age, 9.3 years). The clinicopathological findings of these eight children were investigated. Results. Five patients presented with macroscopic hematuria, while the remaining three were discovered in a school urinary screening program or by chance urinalysis. Six patients developed NS at the onset, and two developed NS later in the course of IgAN. All patients were treated with corticosteroids. At the end of follow-up, heavy proteinuria persisted in four children, one of whom had renal dysfunction at the onset of NS and developed end-stage renal failure, and two of whom developed NS after the onset of IgAN. Proteinuria decreased to less than 1 g/day 3 months after NS in four patients, two of whom showed disappearance of proteinuria afterward. Renal biopsy specimens revealed mesangial proliferation and crescent formation in all patients. The degree of persisting proteinuria was correlated with the presence of glomerular sclerosis, fibrous crescents, tubulo-interstitial changes on light microscopy, and depositions of C3 on immunofluorescence microscopy. Conclusions. Children who developed NS after the onset of IgAN developed renal dysfunction; the prognosis of those who showed chronic histopathological changes on renal biopsy specimens was poor, even in these young children. Received: April 17, 2000 / Accepted: July 4, 2000