Anti-neutrophil cytoplasmic antibody-associated vasculitis after long-term interruption of propylthiouracil therapy

Abstract

    Here, we report a case of myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPOANCA)-related vasculitis. The patient had been treated with propylthiouracil for Basedow’s disease. Propylthiouracil administration was ceased 20 years ago following thyroid surgery.
    A 46-year-old woman with a 26-year history of Basedow’s disease and 12-year history of rheumatoid arthritis was admitted with high fever and pulmonary hemorrhage. Results of laboratory evaluation were: CRP 7.54 mg/dL, Cr 4.54 mg/dL, Hb 6.8 g/dL.
    A diagnosis of MPO-ANCA-associated vasculitis was strongly suggested by positivity for MPO-ANCA (352EU), pulmonary hemorrhage, acute nephritis, and scattered purpura on the limbs. However patient condition did not allow histological confirmation of the diagnosis.
    She was treated with methylprednisolone pulse therapy and prednisolone. Consolidation on chest X-ray and C-reactive protein levels improved rapidly. However, pulmonary hemorrhage was repeated four times with tapering of prednisolone. The titer of MPO-ANCA showed a linear decrease during the clinical course. The recurrence of pulmonary hemorrhage was correlated with the level of CRP.
    MPO-ANCA-associated vasculitis was caused by propylthiouracil. It was reported that serum ANCA may still remain positive in the majority of patients with propylthiouracil-induced MPO-ANCA positive for up to 5 years. This patient developed MPO-ANCA-associated vasculitis from taking propylthiouracil 20 years previously. ANCA was detected in more than 20% of patients treated with propylthiouracil, but only 6.5% of patients showed clinical evidence of vasculitis. Long-term follow-up may be necessary after discontinuation of propylthiouracil.