Treatment of small vessel vasculitis affecting the kidneys

Treatment of vasculitis can be divided into two phases: (i) an induction phase to achieve remission, abate destructive inflammation and minimize scarring; and (ii) the maintenance phase to sustain patients in remission with minimal treatment-related side-effects. A combination of corticosteroids and cytotoxic agents is commonly used as induction therapy. The dose and route of administration of corticosteroids have not been studied adequately, but intravenous (i.v.) bolus doses of methylprednisolone are often administered to patients with severe disease. It has the advantage of fewer side-effects compared to prolonged high dose oral corticosteroids, and the immediate immuno-modulatory effects of the steroid boluses may confer additional therapeutic benefits. It is the general impression that cyclophosphamide is more effective than azathioprine in the acute phase of patients with severe disease. The use of cyclophosphamide by i.v. pulse rather than orally is contentious, and some recent studies have demonstrated its failure to induce sustained remission. Azathioprine with low dose corticosteroids is often employed as long-term maintenance immunosuppression, although low dose cyclophosphamide has also been used for such purpose, which should be withdrawn after 1 year of remission because of its potential side-effects. Clinical and serologic parameters are useful monitors during maintenance therapy. Although serial levels of antineutrophil cytoplasm antibodies (ANCA) correlate with disease activity, some patients remain well despite positive or increasing levels of ANCA. Consequently, whether immunosuppressive therapy should be escalated based on increasing ANCA levels alone remains controversial.