A case with MPO-ANCA associated microscopic polyangiitis induced by Propylthiouracil treatment for hyperthyroidism and a minireview including 79 past cases

Abstract

    A 34 year-old man was admitted to our hospital because of arthralgia, hematuria and positive finding of MPO-ANCA. Basedow disease (BD) was diagnosed when he was30years old. Propylthiouracil (PTU) was administered because he had an allergy to thiamazole. PTU treatment was temporarily discontinued because his thyroid function was well-controlled. However, the exacerbation of BD brought the restart of PTU treatment. Just a month after treatment was restarted, fever, myalgia and arthralgia developed. The examination in hospital revealed hematuria and the positive detection of MPO-ANCA. Furthermore, renal biopsy and chest CT showed necrotizing glomerulonephritis and interstitial pneumonitis, respectively, which were consistent with MPO-ANCA associated vasculitis. The change of PTU for potassium iodide and the treatment of 0.5 mg/kg predonisone allowed us to control both hyperthyroidism and MPO-ANCA associated vasculitis. This case suggests that the booster effect induced by PTU treatment might promote the rapid progress of MPO-ANCA associated vasculitis. Analysis of 79 past cases with PTU-induced ANCA-associated vasculitis showed that this complication was caused by the restart of the treatment with PTU in about 10% of the patients. Therefore, attention should be paid to the possibility of inducing MPO-ANCA even in patients under therestart of the PTU treatment for hyperthyroidism.