[In Process Citation]

Pauci-immune glomerulonephritis and ANCA associated vasculitides (AAV) are chronic autoimmune diseases with necrotizing inflammation of the small vessels, affecting several organ systems with a variety of symptoms, in rarer cases isolated renal manifestation without extrarenal vasculitis. The term "pauci-immune" defines the characteristic absence of immune complexes in the tissues. Circulating antineutrophil cytoplasmic antibodies (ANCA) are of pathogenic and diagnostic relevance. The typical renal manifestation is rapidly progressive glomerulonephritis, progressing to dialysis within weeks without treatment. To prevent diagnostic delay practitioners should measure ANCA promptly in case of acute kidney injury with hematuria. Current immunosuppressive regimens have impressively improved patient and kidney survival, but are far away from being optimal due to a high rate of adverse events and relapses.