Description

• A disease characterized by granulomatous vasculitis involving multiple organs
• The characteristic triad of involvement includes the upper airway (e.g., otitis, sinusitis, nasal mucosa), lungs, and kidneys.
• Other organ systems involved include the skin, joints, and nervous system (peripheral/central).
• As the condition progresses untreated, upper airway erosions, necrotic pulmonary nodules, and renal failure are common.
• Without treatment, mortality rate is high. With treatment, survival rate is ~75–90% at 5 years.
• System(s) affected: upper airways (sinusitis, otitis); cardiovascular; gastrointestinal; nervous; pulmonary; renal/urologic; skin/exocrine
• Synonym(s): antibodies to neutrophilic cytoplasmic antigens (ANCA)-associated vasculitis (to include patients with Wegener and microscopic polyangiitis); granulomatosis with polyangiitis (recommended to replace Wegener as diagnostic term)

Epidemiology

• ~0.4 to 1.2/100,000 persons per year and possibly increasing over the past decade
• Mean age of onset is the mid-40s, but the disease has been described in all age groups.
• Predominant sex: male > female (3:2)

Prevalence
3/100,000 persons

Etiology and Pathophysiology

• Unknown etiology
• Autoimmune phenomena and immune-complex deposition in arterial walls are implicated, and the activation of neutrophils by bacteria or other infectious agents may be important as well.
  • Role of antibodies directed against neutrophils is currently being investigated.
• A specific triggering infectious agent has not been identified.

Genetics
Increased presence in HLA-B8 and HLA-DR2, more recently increase in HLA-DP and genetic variants involved in α₁-antitrypsin and protease-3 (1)