Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 22-18: Membranous Nephropathy + Key Features Download Section PDF Listen +++ ++ Most common cause of primary nephrotic syndrome in adults Caused by immune complex deposition in the subepithelial portion of glomerular capillary walls Associated with Underlying carcinomas Infections, such as hepatitis B and C, endocarditis, syphilis Autoimmune disease, such as systemic lupus erythematosus, mixed connective tissue disease, thyroiditis Coagulopathy, eg, renal vein thrombosis, if nephrotic syndrome is present Certain drugs, such as NSAIDs and captopril Often presents in adults in the fifth and sixth decades + Clinical Findings Download Section PDF Listen +++ ++ May be asymptomatic Edema Frothy urine Venous thrombosis, such as an unprovoked deep venous thrombosis, may be an initial sign Secondary disease associated with symptoms or signs of an underlying infection, such as hepatitis B and C, endocarditis, and syphilis + Diagnosis Download Section PDF Listen +++ ++ Evaluation for secondary causes including serologic testing for Systemic lupus erythematosus Syphilis Viral hepatidites Age- and risk-appropriate cancer screening Elevated levels of circulating PLA2R antibodies Considered diagnostic for idiopathic membranous nephropathy The presence of these antibodies may eliminate the need for kidney biopsy Kidney biopsy Light microscopy: increased capillary wall thickness Silver methenamine stain: a "spike and dome" pattern may be observed owing to projections of excess glomerular basement membrane between the subepithelial deposits Immunofluorescence: IgG and C3 along capillary loops Electron microscopy: discontinuous dense deposits along the subepithelial surface of the basement membrane + Treatment Download Section PDF Listen +++ ++ Underlying causes must be excluded prior to consideration of other treatment Treatment of primary disease depends on the risk of progression of kidney disease Conservative management includes therapy with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker if blood pressure is > 125/75 mm Hg to prevent or ameliorate proteinuria Use of immunosuppressive agents should be limited to those with salvageable kidney function who are at highest risk for progression of kidney disease Patients with nephrotic syndrome despite 6 months of conservative management and serum creatinine < 3.0 mg/dL (265 mcmol/L) may elect therapy with rituximab or with corticosteroids and cyclophosphamide for 6 months Calcineurin inhibitors with or without corticosteroids may also be considered Kidney transplantation