ANCA-positive glomerulonephritis and IgA nephropathy in a patient on propylthiouracil

A 14-year-old girl developed acute renal failure after 3 years therapy with propylthiouracil (PTU) for Grave's disease. Serologic evaluation showed antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 and myeloperoxidase. Renal biopsy showed a crescentic glomerulonephritis (GN) as well as evidence of IgA nephropathy (IgAN). PTU was discontinued and the patient was treated with prednisone and cyclophosphamide. ANCA became negative and renal function improved, but did not normalize. A second biopsy showed evidence of IgA nephropathy only. Propylthiouracil use has been associated with ANCA positive pauci-immune glomerulonephritis, but not with IgA nephropathy. An overlap syndrome between IgAN and ANCA-positive GN, however, has been described. This patient may have had a preexisting IgAN, with acute pauci-immune GN secondary to PTU, or this may be the first description of an overlap syndrome of IgAN and ANCA vasculitis all caused by PTU therapy.