Membranous glomerulonephritis
A common rule of thumb in primary membranous glomerulonephritis (MGN) is that one-third of patients improve spontaneously, one-third progress, and one-third continue to have substantial proteinuria. The rate of spontaneous recovery may be near the truth, but MGN is usually an indolent condition and few studies have run long enough to give accurate outcomes for the remainder. However MGN is an important cause of end-stage renal failure. Treatment regimens that include cyclophosphamide or chlorambucil can improve the outcome of patients at greatest risk of deterioration, but their toxicity has limited their use in randomized studies to the highest risk patients. Steroids alone, and ciclosporin, do not improve long-term outcomes in these studies. Whether anti-B-cell antibodies offer additional benefits requires randomized studies. After confirming the diagnosis of primary MGN it is recommended to maximize supportive therapy and monitor for at least 6 months to give a clear picture of the long-term risk. For patients at lowest risk, supportive management and monitoring alone is recommended. Patients at medium risk (nephrotic range proteinuria but normal and stable glomerular filtration rate), or high risk (very heavy proteinuria, greater than 8 g/day or deterioration of glomerular filtration rate) may justify specific treatment directed at the immune response. For the medium-risk group it is not certain that it is required; for some in the high-risk group it may come too late. Overall outcomes in the high-risk group remain quite poor even with aggressive treatment.