Spontaneous remission of nephrotic syndrome in membranous nephropathy with chronic renal impairment

Background. Spontaneous remission (SR) of nephrotic syndrome, in the absence of immunosuppressive treatment, is relatively common among patients with idiopathic membranous nephropathy (IMN) and normal renal function. However, it has not been reported in patients with chronic renal impairment. Methods. All patients with IMN who had developed SR in the presence of chronic renal insufficiency were identified among the nephrology departments that belong to the Spanish Group for the Study of Glomerular Diseases (GLOSEN). Their characteristics and outcome after SR were studied. Results. Eleven patients were identified. All of them showed renal insufficiency and nephrotic syndrome at the time of renal biopsy. Serum creatinine (Scr) continued to increase in the following months, reaching a peak value of 2.6 +/- 1.5 mg/dL (range 1.7-6.5). Angiotensin converting enzyme inhibitors or spironolactone were prescribed in 10/11 patients at renal biopsy or shortly after it. Nephrotic proteinuria persisted during the first months of follow-up, but it started to spontaneously decrease 12 +/- 7 months (2-30 months) after renal biopsy. Finally, complete (nine patients) or partial (two patients) remission of nephrotic syndrome was observed. Coinciding with proteinuria remission, renal function tended to improve. Nephrotic syndrome relapsed in two patients, accompanied by a rapid deterioration of renal function. In the remaining nine patients, remission persisted throughout a follow-up of 146 +/- 64 months. Mean Scr at the last visit was 1.9 +/- 0.9 mg/dL and proteinuria 0.2 g/24 h. Conclusion. SR of nephrotic syndrome can also be observed in membranous nephropathy patients exhibiting chronic renal impairment.