Endocrine Abstracts

Introduction: Propylthiouracil is a drug used in the treatment of hyperthyroidism and autoimmunity phenomena have been described as a side effect of its use. Despite anti-neutrophil cytoplasmic antibodies (anca) positivity is frequent in patients treated with propylthiouracil, the occurrence of clinically evident vasculitis is rare.

Case report: A 65-year-old woman, diagnosed with hyperthyroidism 2 years ago and treated with propylthiouracil (50+50 mg) since then. She presented to the emergency department with dyspnoea, pleuritic chest pain and hemoptoic cough in the last 2 days. Physical examination showed a peripheral oxygen saturation of 82% and rales in the lower thirds of both lungs. Laboratorial study revealed hypoxia (po2 44.8 mmhg), falling haemoglobin levels (14.0 to 10.1 g/dl in one month), an elevated c-reactive protein (173.3 mg/dl; reference values [rv]:<3 mg/dl) and significant erythrocyturia (6423.5/ul). The chest x-ray showed bilateral infiltrates on the lower pulmonary lobes. She was admitted to the medicine department with the diagnosis of pulmonary-renal vasculitic disorder. Facing the diagnosis of a probable pulmonary-renal vasculitic disorder, she was hospitalized. The patient performed a thoracic ct scan (“ground-glass pattern that suggested diffuse alveolar haemorrhage”) and autoimmune (ancas-mpo>200 u/ml) and thyroid (tsh 0.24 uui/ml; rv: 0.35–4.94; t4 l 0.7 ng/dl; rv: 0.7–1.48; negative trabs; positive anti-tpo antibodies) laboratory studies. A progressive raise of plasmatic creatinine motivated a kidney biopsy that revealed histopathological features of vasculitis. Propylthiouracil treatment was stopped and the patient received metilprednisolone and cyclophosphamide pulses with respiratory, renal and hematologic improvement. She was discharged from the hospital and now she is on remission under prednisolone and azathioprine and euthyroid without specific therapy.

Conclusions: Propylthiouracil induced anca-associated vasculitis is characterized by the positivity for anca of the mpo subtype and by a low recurrence rate when compared with primary vasculitis. This case report raises awareness about the possible systemic side effects of antithyroid agents.