Long-term outcome of heavy proteinuria in patients under 2 years of age.

From January 1985 to July 2000, a retrospective study of 53 patients in Taiwan was performed in order to evaluate the underlying diseases causing heavy proteinuria and the clinical outcome in children under 2 years of age (33 boys and 20 girls). Renal biopsy or autopsy was performed in 26 of the children. Renal pathology revealed 2 patients with congenital nephrosis (CNS) (7.7%), 4 with diffuse mesangial sclerosis (DMS) (15.4%), 4 with minimal change nephrotic syndrome (MCNS) (15.4%), 5 with focal segmental glomerulosclerosis (FSGS) (19.2%), 9 with IgM nephropathy in (34.6%), and 2 with hepatitis B virus-associated membranous glomerulonephritis (7.7%). Based on available histology and family history of heavy proteinuria progressing to end-stage renal disease (ESRD), patients were divided into two groups. Group I comprised 10 patients, including CNS (2 cases), DMS (4 cases), and 4 children with a familial history of heavy proteinuria progressing to ESRD. All patients in group I were initially steroid resistant. After methylprednisolone pulse therapy plus cyclosporin A treatment, no patients with CNS or DMS responded, but the other 4 patients experienced a remission. Group II comprised 43 patients; 19 patients (44.2%) were initially steroid resistant. Of these steroid-resistant patients, all experienced remission after methylprednisolone pulse therapy plus cyclosporin A, except 3 children with FSGS. One experienced a thromboembolic event during his clinical course. In conclusion, steroid-resistant nephrotic syndrome (NS) was more common than steroid-sensitive NS in Chinese patients under 2 years of age. Patients with CNS, DMS, or a family history of heavy proteinuria progressing to ESRD had a poor prognosis. Methylprednisolone pulse therapy plus cyclosporin A treatment achieved remission in some children who were initially steroid resistant. This study indicates that children with conditions associated with poor steroid responsiveness (e.g., CNS, DMS) do not respond to immunosuppressive therapy, but other children under 2 years of age, including those with a family history of progression to ESRD, may benefit from aggressive immunosuppressive therapy.