Subsequent Transition from Minimal Change Disease to Secondary form of Focal Segmental Glomerulosclerosis: Not a Sampling Error yet Still Amenable to Immunosuppressive Therapy

Abstract

Background: Previous studies suggested that the focal and segmental nature of focal segmental glomerulosclerosis (FSGS) may lead to sample error or diagnosis error that results in minimal change disease (MCD) misdiagnosis, or FSGS being missed especially in patients with early lesions or limited glomeruli in the biopsy specimens. Patients and methods: Over the past 5 years, patients were included in the study if they had (a) relapse of nephrotic syndrome (NS), (b) biopsy-proven FSGS without immune deposits, (c) long-remission (years) after biopsy-proven Corticosteroid-refractory NS due to MCD, (c) negative history, clinical examination, radiological scans as well as laboratory and serological tests for autoimmune diseases, infections, malignancy and drugs-side effect. Results: After 3 months of therapy with Losartan alone; Proteinuria decreased only by 22% improvement with a mild decrease in Creatinine clearance (ClCr) by 1.5%. However, the addition of Mycophenolate mofetil (MMF) resulted in a further significant decrease in Pr to 72% compared to Losartan alone. Moreover, there were no significant changes in CrCl after 1- and 2 years of follow up. Our data indicates that such a transition may not be due to inadequate sampling but a new lesion. Initial hemodynamic therapy with Losartan was not adequate and immunosuppressive therapy with MMF significantly improved proteinuria and stabilized their kidney function. The data is promising with regard to the management of patients with such relentless disease. In conclusion, a true transition from MCD to FSGS is amenable to therapy with MMF.