The therapy of idiopathic membranous glomerulonephritis

Abstract

This analysis of IMG has focused on the long-term natural history and current approaches to therapy of this disorder. It seems clear that IMG is intrinsically a relatively benign disease, particularly in certain populations. Risk factors for an unfavorable course can often be identified at the discovery of disease. For example older age at onset, male sex, very heavy proteinuria (greater than 10 g/d), sustained hypertension, impaired renal function, and significant chronic tubulointerstitial lesions in the initial renal biopsy all portend an unfavorable outcome. Contrariwise, patients lacking these prognostic features usually do quite well with a high likelihood of spontaneous complete or partial remissions and stable renal function. Once a complete remission has occurred, whether spontaneous or therapy induced, the long-term evolution of the disorder is quite favorable. Some patients may present with what appears to be "idiopathic" MGN, only to later demonstrate underlying disease, such as neoplasia, chronic viral infection, or systemic lupus erythematosus. Glucocorticoids alone, particularly when administered orally, do not seem to have significant beneficial effects over the long term; however, high-dose intravenous methylprednisolone may at times reverse declining renal function in patients with severe nephrotic syndrome. A small subset of patients may display a remitting and relapsing course following treatment with oral glucocorticoids, resembling to some extent patients with minimal change disease. Combination of alkylating agents, either cyclophosphamide or chlorambucil with glucocorticoids is very likely beneficial for the group of patients having an intrinsically unfavorable prognosis or for patients who demonstrate progressive renal insufficiency. At the present time it is not known whether regimens that involve long-term therapy with oral cyclophosphamide combined with glucocorticoids are superior to, equivalent to, or inferior to regimens that involve the cyclical use of intravenous methyl-prednisolone oral prednisone, and oral chlorambucil. Very long-term use of cyclophosphamide, in excess of 12 months, is probably associated with unacceptable long-term risks, particularly the emergence of neoplasia. Long-term follow-up, more than 10 years, will be required to establish the magnitude of the oncogenic potential of existing shorter term regimens of cyclophosphamide-glucocorticoid combinations and for cyclical regimens using chlorambucil. Further data is required to establish the role of cyclosporine, nonsteroidal antiinflammatory agents and intravenous immunoglobulins in the treatment of patients with IMG. ACE inhibitors, sometimes combined with nonsteroidal antiinflammatory agents, may have some usefulness in patients with heavy proteinuria and declining but not advanced renal failure.(ABSTRACT TRUNCATED AT 400 WORDS)