A 54-year-old male patient was admitted for acute respiratory distress with fever. He was suffering from chronic sinusitis/rhinitis and had persistent otitis for the past 2 months before admission despite several antibiotics courses. He developed a complex pulmonary involvement (embolism and diffuse alveolar hemorrhage) with acute glomerular disease (proteinuria and hematuria but initially no renal failure). Clinical suspicion of Wegener's granulomatosis was confirmed by the positive high titer of antineutrophil cytoplasmic antibodies (c-ANCA with antiproteinase 3 specificity) and despite a negative nasal biopsy. Treatment including cyclophosphamide and methylprednisolone intravenous pulses permitted pulmonary recovery over 4 weeks contrasting with the development of rapidly progressive glomerulonephritis and polyneuropathy of lower limbs. Renal biopsy showed pauci-immune crescentic and necrotizing glomerulonephritis. However, despite additional plasma exchanges, acute kidney injury worsened and the patient ended up in dialysis. Such a dissociated evolution was unexpected in this case since pulmonary and renal involvements reflected the same pathological process (small vessels vasculitis/capillaritis) and the same pathogenic mechanism (antiproteinase 3 autoantibodies).