Granulomatosis With Polyangiitis in Untreated Graves' Disease: A Rare Event.

Antithyroid medications can cause antineutrophil cytoplasmic antibody (ANCA) vasculitis. However, no literature in English describes the coexistence of granulomatosis with polyangiitis (GPA) and untreated Graves' disease. We present a 19-year-old female with thyroid storm and additional complaints of cough, hemoptysis, nasal discharges, polyarthralgia, and skin lesions. Imaging showed peri-hilar cavities and acute-on-chronic sinusitis. Elevated cytoplasmic pattern antineutrophil cytoplasmic antibody (C-ANCA) and anti-proteinase-3 antibody levels plus histopathology of the nasal and skin biopsies suggested GPA. Propranolol, methimazole, and potassium-iodide resolved the thyroid storm. Induction therapy (steroids, rituximab) for GPA provided relief of chronic symptoms stressing the importance of early recognition and swift initiation of treatment.