Systemic vasculitis that typically involves small and medium vessels.
Classic triad consists of upper and lower respiratory tract involvement and pauci-immune glomerulonephritis. Involvement of cutaneous, ocular, musculoskeletal, and peripheral nervous system tissue is also common.
Anti-neutrophil cytoplasmic antibody (ANCA) testing may help with diagnosis, but is not reliable for monitoring disease activity.
Induction of remission was traditionally achieved using cyclophosphamide and high-dose corticosteroids. Methotrexate may effectively substitute for cyclophosphamide in granulomatosis with polyangiitis (GPA) that is not immediately life- or organ-threatening. Remission can be maintained using low-dose corticosteroids and either azathioprine or methotrexate. Rituximab has demonstrated efficacy and safety as an alternative to cyclophosphamide for induction of remission in severe disease, particularly in the setting of disease relapse. However, the optimal timing and dosing for remission maintenance has not been clearly defined, and questions remain regarding the long-term safety profile of rituximab in this population.
With appropriate therapy, patients generally experience prolonged survival with a chronic relapsing course. Most patients develop disease- and/or treatment-related morbidity during the course of their disease.
Long-term management requires careful assessment of disease activity and judicious use of immunosuppressive therapies, emphasising the importance of referral to, and multidisciplinary treatment in, specialised centres.