Lithium carbonate pre-treatment in 131-I therapy of hyperthyroidism.

BACKGROUND The aim of the present work was to investigate the influence of lithium carbonate on the kinetics of radioiodine in the thyroid gland, and the long-lasting effect of radioiodine therapy pre-treated with lithium carbonate in patients with different types of hyperthyreosis and low baseline 24-h thyroidal radioactive iodine uptake (RAIU). MATERIAL AND METHODS The examinations were performed in two groups of patients: in a control group with RAIU 〉 30% and in patients with RAIU 〈 30%. All groups were comparable with regard to age, sex, duration and type of disease (Graves' disease, autonomous node, multinodular goitre). The control group was treated (without lithium) according to described protocol. The second group was pre-treated with lithium carbonate in a dose of 1.0 g/day for 6 days before radioiodine and 3 days thereafter. RESULTS A significant increase in iodide uptake in the thyroid gland was observed during intake of lithium carbonate in 106 out of 128 patients. A decrease of T(3), FT(3), T(4), and FT(4) levels and no significant changes in concentration of TSH were observed as an effect of lithium carbonate treatment. Three years of follow-up show that the results of radioiodine therapy with short lasting lithium carbonate intake are better in the first year and are similar in the second and third years in comparison to the control group. CONCLUSIONS Lithium pre-treatment in hyperthyroid patients with low baseline uptake of radioiodine can increase iodine retention in the thyroid gland independently of the primary disease and permits the use of lower doses of radiation in the therapy.