Vasculitis Syndromes with Renal Involvement: A Review from a Case Series

This review describes vasculitis syndromes that can be diagnosed by kidney biopsy. Microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) typically follow a rapidly progressive course, often leading to end-stage renal failure within a few months, with crescentic glomerulonephritis being the predominant finding on a kidney biopsy. However, some types primarily present with fever and elevated C-reactive protein levels, while the kidney function is preserved; in such cases, a kidney biopsy shows arteriolitis. Eosinophilic granulomatosis with polyangiitis (EGPA) is characterized by eosinophil infiltration and small-artery arteritis, and the renal prognosis is often favorable. Anti-glomerular basement membrane (GBM) glomerulonephritis is a hyperacute form of progressive glomerulonephritis that leads to end-stage renal failure within a few weeks, with most glomeruli exhibiting synchronous necrotizing glomerulitis. Among immune complex-mediated small-vessel vasculitides, many cases of IgA vasculitis correspond to IgA nephropathy; however, cases accompanied by endocapillary hypercellularity have also been observed.