[Treatment of amiodarone-induced hyperthyroidism: corticosteroids or potassium perchlorate? What value do interleukin-6 levels have?].

We report 11 cases of amiodarone-induced hyperthyroidism. We tried to classify them into 2 groups, according to Bartelena et al. (JCEM 81: 2930, 1996). The serum level of interleukin-6 (IL-6) was measured in 7 patients by an immunoenzymometric assay. In type I (cases 1-3) the thyroid was abnormal (goiter, Graves' disease) but IL-6 levels were normal. These cases were successfully managed by the combined use of thionamide drugs (carbimazol or propylthioruacil = PTU) and potassium perchlorate. In type II (case 4), the thyroid seemed to be normal but the serum level of IL-6 was increased, possibly due to a destructive thyroiditis. Treatment with prednisone (40 mg/day) and PTU resulted in a prompt normalization of T3. Contrary to Bartalena et al., we observed cases with normal thyroid and normal levels of IL-6 (cases 5-8) (type III). In these cases prednisone (40 mg/day for 2 weeks) was ineffective but the combined use of thionamide drugs and perchlorate was associated with a normalization of thyroid hormones. This combined treatment seems to be effective in most patients (type I, III). In case of failure of this treatment, a high dose of prednisone (1 mg/kg) could be tried or a lower dosage (40 mg/day) could be used in cases with high IL-6 levels (type II).