musculoskeletal and connective tissue disorders
Microscopic Polyangiitis (MPA)
Key Points
Microscopic polyangiitis is a rare small-vessel vasculitis. Manifestations are variable and may include alveolar hemorrhage, multiple mononeuropathy, and glomerulonephritis. Confirm the diagnosis by testing for antineutrophil cytoplasmic antibodies and by biopsy. Treat with corticosteroids plus an immunosuppressant (eg,cyclophosphamideorrituximabfor severe disease). 