A Rare Case of Nephrotic-Range Proteinuria in Antineutrophil Cytoplasmic Antibodies (ANCA)-Associated Vasculitis

Granulomatosis with polyangiitis (GPA), or Wegener’s granulomatosis as it was formerly referred to, is an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). GPA is characterized as a necrotizing vasculitis with few or no immune deposits termed pauci-immune deposits, predominantly affecting small and medium arterial vessels, involving the upper and lower respiratory tract as well as glomeruli. Renal manifestations are of critical importance because of the progression that may ensue following onset. Glomerulonephritis (primarily rapidly progressive crescentic glomerulonephritis) is quite common, which eventually leads to chronic kidney disease or end-stage renal disease. Usually, patients with GPA and rapidly progressive glomerulonephritis have an elevated plasma creatinine level and urinalysis revealing dysmorphic hematuria, red cell casts, and sub-nephrotic levels of proteinuria. We present a case of a 44-year-old male whose biopsy demonstrated crescentic glomerulonephritis, pauci-immune type proteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA) consistent with GPA, as well as profound proteinuria, an atypical manifestation.