Interferon-Alpha-Induced Destructive Thyroiditis Followed by Graves' Disease in a Patient with Chronic Hepatitis C: A Case Report
J Korean Med Sci. 2011 Dec;26(12):1638-41. Epub 2011 Nov 29.
Published online 2011 November 29. doi: 10.3346/jkms.2011.26.12.1638
Bu Kyung Kim, Young Sik Choi, Yo Han Park, and Sang Uk Lee
Corresponding author.
Address for Correspondence: Young Sik Choi, MD. Department of Internal Medicine, Kosin University College of Medicine, 262 Gamcheon-ro, Seo-gu, Busan 602-702, Korea. Tel: +82.51-990-6102, Fax: +82.51-248-5686, Email: yschoi@kosinmed.or.kr
Received July 4, 2011; Accepted September 25, 2011.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Keywords: Interferons, Destructive Thyroiditis, Graves Disease
INTRODUCTION
Interferon-induced thyroiditis (IIT) is a major clinical problem for patients receiving interferon-alpha (IFN-α) therapy. But, destructive thyroiditis followed by Graves' disease associated with IFN-α therapy is very rarely reported. Herein, we report a rare case of pegylated IFN-α (pegIFN-α) 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-α and ribavirin for 12 months. Results of a thyroid function test and autoantibody levels were normal before IFN-α therapy was initiated. Destructive thyrotoxicosis appeared seven months after the initiation of IFN-α 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-α therapy and remained weakly positive after IFN-α therapy was discontinued.
Keywords: Interferons, Destructive Thyroiditis, Graves Disease
INTRODUCTION
Interferon-alpha (IFN-α), which is the main therapeutic agent used for chronic hepatitis C virus (HCV) infection, is associated with side effects such as flu-like symptoms, hematologic abnormalities and thyroid disease. Prospective studies have shown that up to 40% of patients with HCV infection develop thyroid antibodies during IFN-α therapy (1), and around 15% develop thyroid disease (2). According to Tomer et al. (3), interferon-induced thyroiditis (IIT) can be classified as either autoimmune or non-autoimmune. Autoimmune IIT includes the de novo production of thyroid autoantibody without clinical disease, Hashimoto's thyroiditis, and Graves' disease, while non-autoimmune IIT presents as destructive thyroiditis or non-autoimmune hypothyroidism (3).
The development of thyrotoxicosis during IFN-α treatment may be due to silent destructive thyroiditis or Graves' disease. The development of Graves' disease is a less common side effect of IFN-α therapy than is destructive thyroiditis. Moreover, destructive thyroiditis followed by Graves' disease associated with IFN-α therapy occurs very rarely. Only four cases of destructive thyroiditis followed by Graves' disease asso ciated with IFN-α treatment have been reported in the literature (4, 5). Herein, we report a recent case of pegylated IFN-α (pegIFN-α)-induced destructive thyroiditis followed by transient Graves' disease in a patient with HCV infection.
CASE DESCRIPTION
A 31-yr-old woman with hepatitis C-associated chronic active hepatitis proven on liver biopsy received pegIFN-α (Schering-Plough, Korea) 2b 100 µg weekly and ribavirin 800 mg daily from June 2009 to May 2010. Prior to pegIFN-α therapy, laboratory testing revealed normal concentrations of total T3 at 2.25 nM/L (normal range: 1.1 to 2.9 nM/L), TSH at 1.011 mU/L (normal range: 0.35 to 5.50 mU/L), and free T4 at 15.18 pM/L (normal: 9 to 26 pM/L), in addition to negative titers of antimicrosomal antibody (MSAb) at 18 U/mL (negative < 60 U/mL) and antithyroglobulin antibody (TGAb) at 26.7 U/mL (negative < 60 U/mL). Within two months of pegIFN-α therapy initiation she experienced fever, chills, headaches and dizziness. Seven months into therapy (January 2010), the patient developed mild tremors and palpitation however she had no fever or pain. There was no tenderness and palpable nodule at physical examination. She has no personal and family history of thyroid dysfunction and no specific medication history. She also had not received any test that could interfere with the thyroid scan uptake.
Results of repeated laboratory tests indicated elevated total T3 at 4.26 nM/L, suppressed TSH at 0.009 mU/L, normal total T4 at 148.005 nM/L (normal: 64 to 154 nM/L), and negative titers of MSAb at 27.1 U/mL and TGAb at 31.1 U/mL. Thyrotropin-binding inhibitory immunoglobulin (TBII) was also negative at 2.6 U/L (normal range: 0 to 10 U/L). Tc-99m scintigraphy showed nonvisualization of both thyroid lobes (Fig. 1A). Based on these findings, we diagnosed the patient with interferon-induced destructive thyroiditis and prescribed propranolol 20 mg/d for one month.
A 31-yr-old woman with hepatitis C-associated chronic active hepatitis proven on liver biopsy received pegIFN-α (Schering-Plough, Korea) 2b 100 µg weekly and ribavirin 800 mg daily from June 2009 to May 2010. Prior to pegIFN-α therapy, laboratory testing revealed normal concentrations of total T3 at 2.25 nM/L (normal range: 1.1 to 2.9 nM/L), TSH at 1.011 mU/L (normal range: 0.35 to 5.50 mU/L), and free T4 at 15.18 pM/L (normal: 9 to 26 pM/L), in addition to negative titers of antimicrosomal antibody (MSAb) at 18 U/mL (negative < 60 U/mL) and antithyroglobulin antibody (TGAb) at 26.7 U/mL (negative < 60 U/mL). Within two months of pegIFN-α therapy initiation she experienced fever, chills, headaches and dizziness. Seven months into therapy (January 2010), the patient developed mild tremors and palpitation however she had no fever or pain. There was no tenderness and palpable nodule at physical examination. She has no personal and family history of thyroid dysfunction and no specific medication history. She also had not received any test that could interfere with the thyroid scan uptake.
Results of repeated laboratory tests indicated elevated total T3 at 4.26 nM/L, suppressed TSH at 0.009 mU/L, normal total T4 at 148.005 nM/L (normal: 64 to 154 nM/L), and negative titers of MSAb at 27.1 U/mL and TGAb at 31.1 U/mL. Thyrotropin-binding inhibitory immunoglobulin (TBII) was also negative at 2.6 U/L (normal range: 0 to 10 U/L). Tc-99m scintigraphy showed nonvisualization of both thyroid lobes (Fig. 1A). Based on these findings, we diagnosed the patient with interferon-induced destructive thyroiditis and prescribed propranolol 20 mg/d for one month.
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