MPA – Microscopic Polyangiitis

• Vessels involved: Small vessels.
• Pathology: Necrotizing vasculitis without granulomas.
• Organs:
  • Kidneys: RPGN (very common).
  • Lungs: diffuse alveolar hemorrhage.
  • Skin: palpable purpura.
  • Nerves: mononeuritis multiplex.
• ANCA: MPO-ANCA (p-ANCA).
• Buzzwords: No granulomas, lung-kidney syndrome, palpable purpura.