Thyroid dysfunctions in patients with viral hepatitis treated with interferon-alpha

INTRODUCTION: Many studies have explored that thyroid dysfunctions can be induced by cytokine therapy. Most observations were collected in connection with the treatment of viral hepatitis with interferon-alpha. AIM AND METHODS: Frequency and types of thyroid dysfunction developed during and after recombinant interferon-alpha treatment were studied in 138 patients with viral hepatitis C or B. Therapy lasted 12 months or more, subjects having thyroid dysfunction at the start of therapy were excluded from the study. Thyroid parameters (TSH, FT4, FT3 and anti-TPO) were controlled every third month. In patients in whom thyroid dysfunction occurred the measurements were repeated monthly and other tests were also performed (anti-Tg, IL-6, TSH receptor antibody, thyroid scan and 99mTc-pertechnetate uptake). RESULTS: Thyroid function disturbances were found in 30 (21.7%) patients, 12 of them (8.7%) showed persistent hypothyroidism. Hyperthyroidism was transitory in all cases. The clinical course of thyroid dysfunction might be monophasic (hyper- or hypothyroidism), biphasic (hyperthyroidism followed by hypofunction) or triphasic. Immune and non-immune forms can be clearly distinguished. CONCLUSIONS: Every fifth patient with chronic hepatitis showed thyroid dysfunction during interferon-alpha therapy, it is necessary therefore to control the hormonal status and the thyroid antibody titer. Treated patients have to be informed in advance that as a "side effect" persistent hypothyroidism may develop.