The results confirm the high frequency of ITC. ITC was more frequent in euthyroid patients than in thyrotoxic patients (P < 0.03). Sex, age, thyroid volume and interval between diagnosis and surgery did not significantly influence its incidence. The majority of ITC was represented by microcarcinomas, but in approximately 25% of patients, the tumour size was greater than 2 cm. The role played by FNAC in excluding malignancies proved to be fairly inconclusive.

Objective: A prospective randomized trial was performed to assess the usefulness of iodine supplementation in the prevention of goiter in pregnant women living in marginally iodine-deficient areas. Design: Eighty-six pregnant women were recruited and randomized in two groups and treated daily for up to six months after delivery with 200 mg iodide (group A) or 50 mg iodide (group B). Sixty-seven women (32 in group A and 35 in group B) completed the study. Methods: Thyroid volume (TV), thyroid functional parameters and urinary iodine concentration were determined in all subjects at booking, at the 18th-26th, and the 29th-33rd week of gestation, and at the 3rd and 6th month after delivery. Results: A slight but not significant increase in TV during gestation was observed only in group B. After delivery a progressive decrease in TV was documented in both groups, the final TV being significantly reduced with respect to the initial volume in group A. No significant changes in serum free thyroid hormones and TSH concentrations were found during gestation in either group. Postpartum thyroiditis was observed in 5 women (2 in group A, 3 in group B). No side effects were seen. Conclusion: The present data indicate that in marginally iodine-deficient areas, the administration of iodide is recommended in pregnancy and lactation. In the conditions of the present trial a dose of 50 mg iodide/day is a safe and effective measure in preventing an increase in TV during pregnancy but a dose of 200 mg iodide/day appeared to be more effective without inducing side effects and without enhancing the frequency of post-partum thyroiditis.

Amiodarone, an iodine-rich drug widely used for the treatment of cardiac tachyarrhythmias, may induce either hyperthyroidism or hypothyroidism. Of 467 patients chronically treated with this drug referred to our institution, amiodarone iodine-induced hypothyroidism (AIIH) developed in 28 patients (6%). AIIH patients were subdivided into two groups according to the presence (group A) or absence (group B) of underlying thyroid abnormalities. Thyroid autoantibodies were present in 10 of 19 patients from group A and 0 of 9 patients from group B. The thyroid 24-h radioiodine uptake (RAIU) was evaluated in 15 patients: low values (less than 4%) were found in three patients and detectable values (7-50%) were observed in 12. Perchlorate discharge tests were positive in all four patients tested. Follow-up data were available in 20 patients (16 in group A and four in group B). Hypothyroidism was transient in 12 (60%) and persistent for several months after amiodarone withdrawal in eight (40%). While all patients in group B had transient hypothyroidism, 50% of patients with underlying thyroid abnormalities (group A) had persistent hypothyroidism. Thyroid autoantibodies were found in seven of eight patients with persistent hypothyroidism and in only three of 12 patients with transient hypothyroidism. Conversely, seven of 10 patients with positive thyroid autoantibodies had persistent hypothyroidism and 9 of 10 patients with undetectable thyroid autoantibodies had transient hypothyroidism. These data indicate that: (i) AIIH may develop in patients with or without underlying thyroid abnormalities; (ii) RAIU is inappropriately elevated in many patients with AIIH; (iii) intrathyroidal iodine is not organified; (iv) serum thyroid autoantibodies represent a risk factor for the development of AIIH; (v) AIIH spontaneously remits after amiodarone withdrawal in patients without thyroid abnormalities, but may persist in patients with concomitant thyroid disorders, especially those with circulating thyroid autoantibodies.

Amiodarone, an iodine-rich cardiac drug, may induce thyrotoxicosis (AIT), which can occur in patients with preexisting thyroid abnormalities and in subjects with apparently normal thyroid glands. The pathogenesis of AIT is often due to iodine-induced excessive thyroid hormone synthesis, especially in patients with underlying thyroid disease. In some instances, however, AIT may be related to a destructive process due to amiodarone-induced thyroiditis, resulting in thyroid cell damage and thyroid hormone release into the circulation. Another thyroid inflammatory process, subacute thyroiditis, has been recently reported to be associated with markedly increased serum interleukin-6 (IL-6) levels. To investigate the significance of serum IL-6 levels in AIT, we evaluated in a cross-sectional study the following subjects: 27 AIT patients, 15 with no apparent thyroid abnormalities (AIT-) and 12 with nodular goiter and/or thyroid autoimmune disease (AIT+); 14 euthyroid patients receiving chronic amiodarone therapy; 10 patients with amiodarone-induced hypothyroidism; 56 patients with spontaneous hyperthyroidism due to Graves' disease (n = 35) or toxic adenoma/nodular goiter (n = 21); 20 subjects with nontoxic goiter; and 50 healthy controls. Serum free thyroid hormone concentrations did not differ in patients with amiodarone-induced or spontaneous hyperthyroidism. Mean (+/- SE) serum IL-6 values were as follows: AIT-, 573.5 +/- 78.7 fmol/L (range, 149.4-1145.1); AIT+, 152.7 +/- 46.3 fmol/L (range, < 25-505.6); euthyroid patients receiving chronic amiodarone therapy, 51.4 +/- 10.0 fmol/L (range, < 25-122.5); amiodarone-induced hypothyroidism, 43.8 +/- 8.4 fmol/L (range, < 25-84.3); Graves' disease, 108.2 +/- 18.2 fmol/L (range, < 25-250); toxic adenoma/nodular goiter, 97.6 +/- 10.3 fmol/L (range, < 25-168.9); nontoxic goiter, 47.3 +/- 7.1 fmol/L (range, < 25-106.6); and controls, 37.8 +/- 6.2 fmol/L (range, < 25-99.4). Serum IL-6 values in AIT- patients were markedly higher (P < 0.0001) than those in all other groups. Values in AIT+, although slightly higher, did not significantly differ from those in patients with spontaneous hyperthyroidism. AIT- patients had low 24-h thyroidal radioiodine uptake (RAIU), whereas AIT+ had inappropriately low normal to high (9-58%) RAIU values in the presence of excess iodine. The presence of markedly elevated serum IL-6 concentrations and low thyroidal RAIU values in patients with AIT without underlying thyroid disease suggests the presence of amiodarone-induced thyroiditis as the etiology of thyrotoxicosis. Treatment of 2 such patients with prednisone was associated with a dramatic reduction and prompt normalization of IL-6 and thyroid hormone values.(ABSTRACT TRUNCATED AT 400 WORDS)