Comparison of the long-term efficacy of low dose 131I versus antithyroid drugs in the treatment of hyperthyroidism.

OBJECTIVE: In China the therapeutic options to treat hyperthyroidism comprise antithyroid drugs (ATDs), radioiodine (131I) therapy and surgery. Physicians in China avoid the risk of hypothyroidism as a consequence of either treatment because patients from rural districts cannot easily comply with long-term medication. Therefore, we prospectively assessed the efficacy and safety of 131I versus ATDs. METHODS: Of 2021 hyperthyroid patients 460 without any previous treatment were enrolled in a 9-year prospective, randomized, open-label blinded endpoint study and randomly assigned to receive either 131I or ATD. Follow-up was 98.4+/-5.5 months. The primary outcome was euthyroidism, persistent hyperthyroidism, recurrence, and hypothyroidism. RESULTS: Euthyroidism was achieved in 69.9 and 41.2% using either 131I or ATD, 2.4 and 19.2% remained hyperthyroid, hypothyroidism occurred in 21.5 and 9.0%, recurrence in 6.2 and 30.5%, respectively. Time to cure was shorter with 131I (44.8 vs. 74.8 months, P<0.01). Goiter size extended time to cure. Hard goiter, complications, or ophthalmopathy were protective against hypothyroidism after 131I therapy. Large goiters or long courses of hyperthyroidism predicted failure of ATD treatment. CONCLUSION: This study showed a shorter cure time using 131I. Time to remission in ATD patients was shorter during the first 9 months. Thereafter, the 131I group showed a higher remission rate. Low long-term hypothyroidism and low recurrence or persistent hyperthyroidism rates were achieved with our 131I dose regimen, regardless of the underlying disease. Lesser 131I activity was used as compared with current guidelines. Within limitations, our concept may simplify procedures in other geographical regions.

Fatality after cardiac arrest in thyrotoxic periodic paralysis due to profound hypokalemia resulting from intravenous glucose administration and inadequate potassium replacement.

BACKGROUND: Thyrotoxic periodic paralysis (TPP) is a variant of periodic paralysis (PP) that occurs in patients with underlying mutations in genes for cation channels, if they develop thyrotoxicosis. It is disabling, and fatalities sometimes occur. Here, we present a patient with TPP who developed hypokalemic paralysis that was probably aggravated by the administration of a carbohydrate, probably contributing to, if not causing, a fatal outcome. SUMMARY: A 30-year-old Chinese patient received (131)I treatment for Graves' disease (GD) in our hospital. Three days later in the middle of the night, he developed aggravating paralytic symptoms after a heavy evening meal. The next morning, he was seen in a small clinic and was treated with 1250 mL 5% glucose containing 25 mL 10% potassium chloride (KCl). By early afternoon, he had not improved and was transferred to a city hospital, arriving with grade I muscle strength and severed facial and bulbar paralysis that was shortly followed by cardiac arrest with failure of resuscitation. Shortly before he died, his serum K(+) was 1.15 mEq/L (normal=3.5-5). CONCLUSIONS: We postulate that severe hypokalemia developed in our patient in part in response to the high intravenous glucose load that he received. We advocate caution against using intravenous glucose solutions for potassium administration in patients with TPP and recommend a review of guidelines suggesting this form of treatment. In rural settings with limited resources, we favor oral potassium, not to exceed 100 mEq per day, and transfer to a modern medical facility in settings where muscle weakness is developing in patients with TPP.

Striving for euthyroidism in radioiodine therapy of Graves' disease: a 12-year prospective, randomized, open-label blinded end point study.

BACKGROUND: In China, use of radioiodine therapy is problematic because of the need for lifelong levothyroxine substitution. Our aim was to find an optimum dosing strategy for (131)I treatment of hyperthyroidism due to Graves' disease (GD). We attempted to achieve euthyroidism to avoid long-term levothyroxine treatment. METHODS: Six hundred patients with GD were randomized into five groups, each comprising 120 individuals, to receive an individual (131)I activity selected from five different ascending activity ranges. The ranges were modulated according to a clinical score system. Follow-up was extended over a 12-year time frame. The primary outcomes were euthyroidism, hyperthyroidism, hypothyroidism, and recurrent hyperthyroidism. The secondary endpoint was the accumulated (131)I activity needed to achieve euthyroidism. RESULTS: Out of 682 screened patients, 600 entered the study in 1997. Five hundred twenty-nine completed the last follow-up visit at the end of the study in 2009. Group 3 was identified as the study arm that received the optimum radioiodine activity, with 71.8% of the patients maintaining a euthyroid status, 5.8% remaining hyperthyroid, and 22.3% becoming hypothyroid by the end of the study. This group received 1.85-4.07 MBq per gram of thyroid tissue (average administered activity 261 ± 162 MBq). Over the 12-year follow-up period, the recurrence rate was 13.6%. The efficacy of (131)I treatment was related to activities modulated by a clinical score (χ(2) = 82.1, p = 0.000). CONCLUSION: Our protocol effectively treated hyperthyroidism and significantly reduced the hypothyroidism rate. It may be preferable to the intentional induction of permanent hypothyroidism recommended by many experts.

[Comparison of the effectiveness of 131-I and antithyroid drugs in the treatment of Graves' disease in children].

OBJECTIVE: To comprehensively evaluate the treatment of Graves' disease in children with (131)I and antithyroid drugs (ATD) and to quantitatively assess the advantages and disadvantages of them. METHODS: The authors examined the outcome of (131)I and ATD treatment in children with Graves' disease at the Hospital of Dongshan District in Guangzhou during the period 1997 to 2002. Each of the 2 groups of patients consisted of 40 patients ranging in age from 8 to 14 years (mean 10.7 +/- 2.2). The groups were similar in age, gender, length of disease, goiter size, and initial serum thyroid hormone levels. Thyroid status was assessed > 2 year after the therapies started. The efficacy of the therapeutic methods were scored as follows: the children whose disease was cured were marked 0, and those who had improvement but were not cured were marked 1, and those who remained unchanged were marked 2. After treatment the patients who were demonstrated to have ophthalmopathy or more severe ophthalmopathy, hyperthyroid heart disease, liver function damage and leukopenia were marked 2 respectively, and those who showed temporary hypothyroidism and permanent hypothyroidism were marked 1 and 2, respectively. Those who had a relapse of the disease after being cured were marked 2. The effects of two groups and total scores were compared. RESULTS: The total score of the group treated with (131)I was 34; and the median score was 1; the total score of the group treated with ATD was 69, and the median score was 1.5; the difference between the two groups was statistically significant (P < 0.01). When these two groups were compared, the advantage of (131)I in the treatment of this disease was clear. The incidences of ophthalmopathy and improvement of ophthalmopathy of the two groups were not significantly different (P > 0.05). No significant difference was found in incidence of hypothyroidism between the two groups (P > 0.05). There was no significant worsening or new development of ophthalmopathy or hypothyroidism after (131)I and ATD treatment. The rate of relapse of hyperthyroidism among patients cured with (131)I was significantly lower than that among patients cured with ATD (P < 0.05). In the patients treated with (131)I the incidences of hyperthyroid heart disease, liver function damage, leukopenia and so on were significantly lower than those of patients treated with ATD (P < 0.05). CONCLUSIONS: (131)I therapy was superior to the ATD in treatment of the children with Graves' disease. Observations for more than 2 years after treatment with (131)I showed that there were no harmful side effects or complications. (131)I can be recognized as the safer, more convenient and effective treatment than ATD for Graves' disease in children.