End-stage kidney at the onset of nephrotic syndrome in a 4-year-old girl.

A previously healthy Japanese girl aged 4 years suddenly developed idiopathic nephrotic syndrome (INS) associated with acute renal failure (ARF). Despite prompt initiation of hemodialysis and prednisolone treatment, her ARF did not recover. A percutaneous renal biopsy performed within a month from the onset of INS revealed lesions of end-stage kidney, which is unusual for the acute stage of INS. Although the etiology of her ARF remains speculative, an acute exacerbation of an underlying chronic disease, such as non-nephrotic focal segmental glomerulosclerosis might be the cause.