The onset of Graves' disease during the clinical course of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA)-associated glomerulonephritis.

A 47-year old man presented with atrial fibrillation, weight loss, hand tremor, and hyperperspiration concurrent with the reactivation of the disease activity of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA)-associated glomerulonephritis. Laboratory findings indicated that the hyperthyroidism had already existed when glomerulonephritis was detected, and Graves' disease became evident while decreasing the dose of prednisolone. Although the levels of thyroid-stimulating hormone receptor antibody, antithyroid peroxidase antibody, and myeloperoxidase antibody increased, both disease activities were suppressed by increasing the dose of prednisolone. This case indicates that MPO-ANCA-associated glomerulonephritis and Graves' disease may share a common pathogenesis.