Guided by organ manifestations. In many instances includes infections and neoplasms, which must be ruled out prior to beginning immunosuppressive therapy. Consideration must also be given for diseases that can mimic vasculitis (Table 159-1).
Treatment: Vasculitis Therapy is based on the specific vasculitic syndrome and the severity of its manifestations. Immunosuppressive therapy should be avoided in disease that rarely results in irreversible organ system dysfunction or that usually does not respond to such agents (e.g., isolated cutaneous vasculitis). Antiviral agents play an important role in treating vasculitis occurring with hepatitis B or C. Glucocorticoids alone may control giant cell arteritis and Takayasu arteritis. Therapy that combines glucocorticoids with another immunosuppressive agent is particularly important in syndromes with life-threatening organ system involvement, especially active glomerulonephritis. Frequently used agents: - Prednisone 1 (mg/kg)/d initially, then tapered.
- Cyclophosphamide 2 (mg/kg)/d, adjusted to avoid severe leukopenia. Morning administration with a large amount of fluid is important in minimizing bladder toxicity. IV cyclophosphamide (15 mg/kg every 2 weeks for three doses then every 3 weeks thereafter) can also induce remission but may be associated with a higher relapse rate. Treatment should be limited to 3-6 months followed by transition to maintenance therapy with methotrexate or azathioprine.
- Rituximab 375 (mg/m2)/week for 4 weeks. As effective as cyclophosphamide to induce remission of granulomatosis with polyangiitis (Wegener's) or microscopic polyangiitis.
- Methotrexate in weekly doses up to 25 mg/week may be used to induce remission in granulomatosis with polyangiitis (Wegener's) or microscopic polyangiitis pts who do not have immediately life-threatening disease or cannot tolerate cyclophosphamide. It may also be used for maintaining remission after induction with cyclophosphamide. Cannot be used in renal insufficiency or chronic liver disease.
- Azathioprine 2 (mg/kg)/d. Less effective in treating active disease but useful in maintaining remission after induction with cyclophosphamide.
- Mycophenolate mofetil 1000 mg bid. Less effective than azathioprine to maintain remission but an option in pts who cannot take or who have relapsed with methotrexate and azathioprine.
- Plasmapheresis may have an adjunctive role in rapidly progressive glomerulonephritis.
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For a more detailed discussion, see Langford CA, Fauci AS: The Vasculitis Syndromes, Chap. 385, p. 2179; in HPIM-19. |