[A case of childhood IgA nephropathy who developed rapidly progressive glomerulonephritis in one-year clinical course].

A 10-year-old girl who presented with microscopic hematuria, proteinuria and normal renal function has been followed up for the past two years. At the first examination, renal biopsy revealed focal/segmental lesions accompanying by occaisional necrosis and small crescents. Diagnosis of IgA nephropathy was given by light, electron and immunofluorescent microscopic findings. She started on the treatment with dipyridamol and was followed up for one year without any serious complications. Thereafter, she suddenly developed severe deterioration of renal function (serum creatinine 2.7 mg/dl) with nephrotic syndrome and hypertension. The second renal biopsy done at this time indicated the presence of typical crescentic glomerulonephritis with mesangial proliferation. No vasculitis was noted. She was intensively treated with steroids, anticoagulants and other medication and responded fairly well clinically. The third renal biopsy performed 5 months afterwards demonstrated marked histological improvement, but there was still present mesangial proliferation and varied degrees of sclerotic changes with fibrocellular crescents. Focal interstitial fibrosis and collapsed tubules were also seen. At present, 5 months after the last renal biopsy, she has improved much better and her serum creatinine decreased to 1.9 mg/dl, although proteinuria of 3 g/day still persists. It is suggested that only a small segmental necrosis with crescent formation in IgA nephropathy should be considered as an important indicator of disease activity in the evaluation of prognosis.