RT Journal A1 Maher JF T1 ON treating glomerulonephritis JF Archives of Internal Medicine JO Archives of Internal Medicine YR 1979 FD May 1 VO 139 IS 5 SP 509 OP 509 DO 10.1001/archinte.1979.03630420005003 UL http://dx.doi.org/10.1001/archinte.1979.03630420005003 AB A patient seeks treatment for hematuria and proteinuria and undergoes diagnostic examination that excludes urologic lesions and does not reveal characteristic findings of specific renal diseases, such as acute poststreptococcal glomerulonephritis. To clarify further the nature of the disease, a renal biopsy is performed. It is naive to anticipate that renal histopathology will regularly provide a diagnosis. Of course, recognition of amyloid or diabetic nephropathy identifies lesions, the natural histories of which are well known. More often a combination of immunofluorescent staining for inimunoglobulins or fibrin or both, coupled with assessment of proliferation of the distinct types of intraglomerular cells, allows a descriptive pathologic diagnosis, such as membranous glomerulopathy, IgA mesangial glomerulonephritis, or the crescentic form of proliferative glomerulonephritis, which is also called rapidly progressive glomerulonephritis. These lesions have multiple causes. For example, IgA nephritis may be the renal lesion of Henoch-Schönlein purpura, of systemic lupus erythematosus, or of Berger's