Endocrine Abstracts

Objective: To study the efficacy of lithium and perchlorate in special cases of hyperthyroidism: thioamide-resistant or iodine-induced thyroxicosis/thyrotoxic pre-crisis, hematological adverse effects of methimazole, leukopenia of other causes.

Material and methods: Twenty-seven hyperthyroid patients received lithium carbonate and/or potassium perchlorate, majority after methimazole-therapy (associated with folic acid in leukopenia). We followed the clinical course, TSH, FT₄, TT₃ and hemogram during therapy.

Results: Thyrotoxic pre-crisis appeared in 14.8% and moderate overt hyperthyroidism in 85.2% of patients (majority due to autoimmune thyroid diseases). Methimazole induced leukopenia in 18 cases: in 14 the initial high doses (30–60 mg/day), in 4 the chronic treatment. In four subjects interferon provoked leukopenia. Methimazole-therapy was insufficient in 3 and caused allergy in 2 cases. We introduced lithium carbonate in 250–1000 mg daily doses, and the leukocyte count begun to rise on the second day, with normalization on fifth day. Lithium-therapy (perchlorate in 4 cases) normalized thyroid function on the 3–4th week in 8 cases, and reduced the plasma levels of thyroid hormones with about 38.8% in 19 patients. Four subjects underwent thyroidectomy after euthyroid status was reached, 6 continued lithium-therapy with lower doses, and 9 patients received gradually reduced doses of lithium and methimazole (5–15 mg/day) necessary to keep thyroid function and bloodcount normal. Lithium was ceased due to adverse effects in 6 cases (3 gastrointestinal, 3 psychical); we lost the contact with 2 patients. Mean duration of treatment was 4.4 months for lithium and 1.1 month for perchlorate.

Conclusion: Lithium/perchlorate with or without small doses of thioamide may be a therapeutic option when thioamides alone are insufficient or not tolerated: they improve both the hyperthyroid state and the hematological disorders. Euthyroid status was reached, thus thyroidectomy could be performed if was necessary. Lithium provoked gastrointestinal and psychic complications, while the short-term perchlorate therapy did not cause any side effects.