MN is characterized by biopsy findings on light microscopy consisting of thickening of all of the glomerular basement membrane (GBM) without cellular proliferation or infiltration; immunofluorescence reveals IgG and C3 staining along the GBM. Approximately 75% of cases of MN are idiopathic, with the remaining thought to be associated with underlying conditions such as hepatitis B and autoimmune diseases, certain medications including NSAIDs, gold, penicillamine, and captopril, and in association with new malignancies. It is not possible to differentiate between idiopathic and secondary MN based on histopathology or immunofluorescence.
N03.2 – Chronic nephritic syndrome with diffuse membranous glomerulonephritis
77182004 – Membranous glomerulonephritis