This, in turn, stimulates release of proteases and oxidants by the mesangial and epithelial cells, damaging the capillary walls and causing them to become "leaky". In addition, the epithelial cells also seem to secrete an unknown mediator that reduces nephrin synthesis and distribution.Within membranous glomerulonephritis, especially in cases caused by viral hepatitis, serum C3 levels are low.Similar to other causes of nephrotic syndrome (e.g., focal segmental glomerulosclerosis or minimal change disease), membranous nephropathy is known to predispose affected individuals to develop blood clots such as pulmonary emboli. Membranous nephropathy in particular is known to increase this risk more than other causes of nephrotic syndrome though the reason for this is not yet clear. Morphology
The defining point of MGN is the presence of subepithelial immunoglobulin-containing deposits along the glomerular basement membrane (GBM). By light microscopy, the basement membrane is observed to be diffusely thickened. Using Jones stain, the GBM appears to have a "spiked" or "holey" appearance. On electron microscopy, subepithelial deposits that nestle against the glomerular basement membrane seems to be the cause of the thickening. Also, the podocytes lose their foot processes. As the disease progresses, the deposits will eventually be cleared, leaving cavities in the basement membrane. These cavities will later be filled with basement membrane-like material, and if the disease continues even further, the glomeruli will become sclerosed and finally hyalinized. Immunofluorescence microscopy will reveal typical granular deposition of immunoglobulins and complement along the basement membrane.Although it usually affects the entire glomerulus, it can affect parts of the glomerulus in some cases.
It must be kept in mind, however, that each of the 5 medications also carry their own risks, on top of prednisone.The twin aims of treating membranous nephropathy are first to induce a remission of the nephrotic syndrome and second to prevent the development of end-stage kidney failure. A meta-analysis of four randomized controlled trials comparing treatments of membranous nephropathy showed that regimes comprising chlorambucil or cyclophosphamide, either alone or with steroids, were more effective than symptomatic treatment or treatment with steroids alone in inducing remission of the nephrotic syndrome. Prognosis
About a third of untreated patients have spontaneous remission, another third progress to require dialysis and the last third continue to have proteinuria, without progression of kidney failure. Terminology
The closely related terms membranous nephropathy (MN) and membranous glomerulopathy both refer to a similar constellation but without the assumption of inflammation. Membranous nephritis (in which inflammation is implied, but the glomerulus not explicitly mentioned) is less common, but the phrase is occasionally encountered. These conditions are usually considered together. By contrast, membranoproliferative glomerulonephritis has a similar name, but is considered a separate condition with a distinctly different causality. Membranoproliferative glomerulonephritis involves the basement membrane and mesangium, while membranous glomerulonephritis involves the basement membrane but not the mesangium. (Membranoproliferative glomerulonephritis has the alternate name "mesangiocapillary glomerulonephritis", to emphasize its mesangial character.) References


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