Thyroid hormonal disturbances related to treatment of hepatitis C with interferon-alpha and ribavirin

OBJECTIVE: To characterize thyroid disturbances induced by interferon-alpha and ribavirin therapy in patients with chronic hepatitis C. INTRODUCTION: Interferon-alpha is used to treat chronic hepatitis C infections. This compound commonly induces both autoimmune and non-autoimmune thyroiditis. METHODS: We prospectively selected 26 patients with chronic hepatitis C infections. Clinical examinations, hormonal evaluations, and color-flow Doppler ultrasonography of the thyroid were performed before and during antiviral therapy. RESULTS: Of the patients in our study, 54 percent had no thyroid disorders associated with the interferon-alpha therapy but showed reduced levels of total T3 along with a decrease in serum alanine aminotransferase. Total T4 levels were also reduced at 3 and 12 months, but free T4 and thyroid stimulating hormone (TSH) levels remained stable. A total of 19 percent of the subjects had autoimmune interferon-induced thyroiditis, which is characterized by an emerge of antithyroid antibodies or overt hypothyroidism. Additionally, 16 percent had non-autoimmune thyroiditis, which presents as destructive thyroiditis or subclinical hypothyroidism, and 11 percent remained in a state of euthyroidism despite the prior existence of antithyroidal antibodies. Thyrotoxicosis with destructive thyroiditis was diagnosed within three months of therapy, and ultrasonography of these patients revealed thyroid shrinkage and discordant change in the vascular patterns. DISCUSSION: Decreases in the total T3 and total T4 levels may be related to improvements in the hepatocellular lesions or inflammatory changes similar to those associated with nonthyroidal illnesses. The immune mechanisms and direct effects of interferon-alpha can be associated with thyroiditis. CONCLUSION: Interferon-alpha and ribavirin induce autoimmune and non-autoimmune thyroiditis and hormonal changes (such as decreased total T3 and total T4 levels), which occur despite stable free T4 and TSH levels. A thyroid hormonal evaluation, including the analysis of the free T4, TSH, and antithyroid antibody levels, should be mandatory before therapy, and an early re-evaluation within three months of treatment is necessary as an appropriate follow-up.

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

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.

Thyroid dysfunction in hepatitis C individuals treated with interferon-alpha and ribavirin: a review

Hepatitis C (HCV) is now the main cause of chronic hepatic disease, cirrhosis and hepatocellular carcinoma. Several extrahepatic diseases have been associated with chronic HCV infection, and in most cases appear to be directly related to the viral infection. Thyroid disorders are common in patients with chronic HCV. Some patients with chronic hepatitis C experience thyroid problems, and thyroid dysfunction may also be a side effect of interferon-based treatment. The principal risk factor for developing thyroid disease in the course of antiviral therapy is the previous positivity for anti-thyroid antibodies (anti-thyroid peroxidase) especially in older women. Screening for autoantibodies and serum thyroid-stimulating hormone is recommended before, during and after interferon-alpha treatment, and patients should be informed of the risk of thyroid dysfunction. This review includes a summary of thyroid disease associated with chronic HCV infection, interferon-alpha and ribavirin for treatment of HCV and potential to induce thyroid dysfunction.

Effect of polychlorinated biphenyl (Aroclor 1260) on histology of kidney and thyroid of rats.

Gross histological alteration in kidney and thyroid structures were observed in male Wistar rats fed polychlorinated biphenyls (PCBs; Aroclor 1260) at 50 and 100 ppm level in normal commercial diet for 120 days. While the kidney showed glomerulonephritis, degenerative changes in the proximal and distal tubules and increased cellularity of glomeruli, thyroid showed degeneration of follicles, fibrosis of follicles and lymphocytic infiltration followed by thyroiditis.