RESUMO
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.