Granulomatosis with Polyangiitis

Wegener’s granulomatosis (WG) or granulomatosis with polyangiitis (GPA) (see below) is a rare and potentially lethal systemic necrotizing granulomatous vasculitis (of the small- and medium-sized arteries and veins) classically involving the upper and lower respiratory tracts with frequent involvement of the kidneys. However, limited or incomplete forms (typically without renal involvement) are common. Although first described by Klinger as a form of polyarteritis nodosa in 1931, it is named after the German pathologist Friedrich Wegener, who recognized the unique nature of the condition and established Wegener’s granulomatosis as a distinct clinicopathologic entity. The average age of onset is around 40 years. Recently, three professional bodies proposed to change the honorific eponym of Wegener’s granulomatosis to the more descriptive term “granulomatosis with polyangiitis (Wegener’s), abbreviated as GPA. The new name recognizes the main pathologic feature (granulomatous inflammation) and reflects the frequent vasculitic involvement of multiple types of vessels (polyangiitis). It is expected that the parenthetical reference to Wegener’s will gradually be phased out as the new terminology becomes accepted. This chapter will continue to utilize the older terminology of Wegener’s granulomatosis, due to familiarity, but acknowledges the proposed change.