Evidence-based clinical practice guidelines for rapidly progressive glomerulonephritis 2014

The World Health Organization defines rapidly progressive glomerulonephritis (RPGN)/rapidly progressive nephritic syndrome as an abrupt or insidious onset of macroscopic hematuria, proteinuria, anemia, and rapidly progressing renal failure. The Research Committee of Progressive Glomerular Disease of the Ministry of Health, Labor and Welfare of Japan and the Japanese Society of Nephrology defined RPGN as rapidly progressing renal failure within several weeks to several months that is associated with urinary findings such as proteinuria, hematuria, red blood cell casts, and granular casts indicating glomerulonephritis. Without treatment, most patients will develop end-stage renal disease. RPGN is one of the clinical syndromes resulting from glomerulonephritis. In most cases of RPGN, the histopathological diagnosis is necrotizing crescentic glomerulonephritis (NCGN). NCGN is classified into three types—linear, granular, and paucity-immune pattern—based on immunofluorescence microscopic findings. A linear pattern indicates anti-glomerular basement disease, including in situ immune complex formation disease based on the Chapel Hill consensus criteria (2012). Granular staining is seen in circulating immune complex diseases such as systemic lupus erythematosus and IgA vasculitis. Most cases with the paucity-immune pattern are glomerulonephritis induced by antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis. Myeloperoxidase (MPO)-specific ANCA-associated vasculitis is more widely known than proteinase 3 ANCA-associated vasculitis in Japan.