Interferon-Alpha-Induced Destructive Thyroiditis Followed by Graves' Disease in a Patient with Chronic Hepatitis C: A Case Report

ABSTRACT

Interferon-induced thyroiditis (IIT) is a major clinical problem for patients receiving interferon-alpha (IFN-alpha) therapy. But, destructive thyroiditis followed by Graves' disease associated with IFN-alpha therapy is very rarely reported. Herein, we report a rare case of pegylated IFN-alpha (pegIFN-alpha) induced destructive thyroiditis followed by Graves' disease in a patient with HCV infection. A 31-yr-old woman suffered from chronic active hepatitis C and was treated with pegIFN-alpha and ribavirin for 12 months. Results of a thyroid function test and autoantibody levels were normal before IFN-alpha therapy was initiated. Destructive thyrotoxicosis appeared seven months after the initiation of IFN-alpha therapy, followed by Graves' thyrotoxicosis two months after the cessation of therapy. The diagnoses of destructive thyroiditis and Graves' disease were confirmed by the presence of TSH receptor antibodies in addition to Tc-99m scintigraphy findings. The patient's antithyroglobulin antibody titer increased gradually during IFN-alpha therapy and remained weakly positive after IFN-alpha therapy was discontinued.