chronic interstitial lung disease with fbrosis is not a classical feature of GPA. It is possible but more commonly seen in the presence of MPO-ANCAs with or without systemic vasculitis (microscopic polyangiitis).

Surgical and open-wedged lung biopsies, targeting nodules or consolidation lesions, have a good diagnostic yield of up to 91% [5, 53]. In practice, obtaining these biopsies can be diffcult, but they can be necessary to confrm the diagnosis, especially in patients with disease limited to the lungs.

Pulmonary embolism (<5% of patients at diagnosis) may be a sign of active GPA, especially in patients with otherwise unexplained chest pain and sudden and/or persistent shortness of breath.

Fig. 8.8  A chest radiograph (anteroposterior) in a patient with granulomatosis with polyangiitis. Diffuse bilateral bronchoalveolar infltrate corresponding to massive alveolar hemorrhage

Asthma is not a feature of GPA and may suggest eosinophilic granulomatosis with polyangiitis. A coincidental association of the two conditions remains possible, and an eosinophilic variant form of GPA has been described, sometimes with asthma [57, 58] and/or as a possible overlapping form of immunoglobulin (Ig)4-related diseases [59, 60].

Kidney and Urological Manifestations

Kidney Manifestations

Renal disease represents the third most frequent manifestation of GPA and presents as focal, segmental, crescentic, necrotizing, and pauci-immune glomerulonephritis. The frst sign is microscopic hematuria, with (or without) red blood cell casts. Increased proteinuria usually follows before renal function worsening, which can rapidly lead to end-stage renal disease. The combination of alveolar hemorrhage and renal disease defnes pulmonary renal syndrome, which can occur in GPA as well as in microscopic polyangiitis, anti-­glomerular basement membrane (GBM) antibody disease (Goodpasture syndrome), and systemic lupus erythematosus. A kidney biopsy is sensitive in patients with urine sediment abnormalities, and histology can help in predicting renal prognosis (with a simple classifcation: focal, crescentic, mixed, and sclerotic) [61].

Rarer renal manifestations include granulomatous nephritis, interstitial granulomatous renal masses, and aneurysms of the branches of the renal arteries, including their intraparenchymal portions [62, 63]. A possible (but low) increase in the frequency of kidney cancer has been suggested by some studies or case reports, but most were probably related to bladder toxic treatments [64].

Fig. 8.9  A chest radiograph (anteroposterior), a CT scan (coronal), and a 3D volume reconstruction of the tracheobronchial tree in a patient with granulomatosis with polyangiitis. Major lengthy and multisegmental ste-

nosis of the left main bronchus causing partial left lung atelectasis (bronchus intermedius is also laterally narrowed). Note the thickening of the narrowed bronchial wall, suggesting granulomatous infltration