New developments in the treatment of Wegener's granulomatosis, polyarteritis nodosa, microscopic polyangiitis, and Churg-Strauss syndrome.

With the opportunity for long-term follow-up, it has been appreciated that disease severity may vary considerably in patients with Wegener's granulomatosis, polyarteritis nodosa, microscopic polyangiitis, and Churg-Strauss syndrome. Although combined therapy with cyclophosphamide and glucocorticoids continues to be the foundation of treatment, concerns have increased about the toxicities of this regimen. As illustrated by studies on Wegener's-related subglottic stenosis and endobronchial involvement, it has also become apparent that some disease manifestations may not respond to this therapy. Recent therapeutic investigations have therefore focused on identifying approaches that are less toxic and that are based on anatomic involvement and disease severity. The study of polyarteritis nodosa has additionally been affected by proposed changes in classification that would make this condition a separate entity from microscopic polyangiitis. As progress is made in defining the clinical significance of this nomenclature, the prognostic factors in these patients have also been examined, which may be helpful in guiding therapeutic decisions.