The effect of short-term treatment with lithium carbonate on the outcome of radioiodine therapy in patients with long-lasting Graves' hyperthyroidism.

OBJECTIVE: The outcome of radioiodine therapy (RIT) in Graves' hyperthyroidism (GH) mainly depends on radioiodine (131I) uptake and the effective half-life of 131I in the gland. Studies have shown that lithium carbonate (LiCO3) enhances the 131I half-life and increases the applied thyroid radiation dose without affecting the thyroid 131I uptake. We investigated the effect of short-term treatment with LiCO3 on the outcome of RIT in patients with long-lasting GH, its influence on the thyroid hormones levels 7 days after RIT, and possible side effects. METHODS: Study prospectively included 30 patients treated with LiCO3 and 131I (RI-Li group) and 30 patients only with 131I (RI group). Treatment with LiCO3 (900 mg/day) started 1 day before RIT and continued 6 days after. Anti-thyroid drugs withdrawal was 7 days before RIT. Patients were followed up for 12 months. We defined a success of RIT as euthyroidism or hypothyroidism, and a failure as persistent hyperthyroidism. RESULTS: In RI-Li group, a serum level of Li was 0.571 ± 0.156 mmol/l before RIT. Serum levels of TT4 and FT4 increased while TSH decreased only in RI group 7 days after RIT. No toxic effects were noticed during LiCO3 treatment. After 12 months, a success of RIT was 73.3% in RI and 90.0% in RI-Li group (P < 0.01). Hypothyroidism was achieved faster in RI-Li (1st month) than in RI group (3rd month). Euthyroidism slowly decreased in RI-Li group, and not all patients became hypothyroid for 12 months. In contrast, euthyroidism rapidly declined in RI group, and all cured patients became hypothyroid after 6 months. CONCLUSION: The short-term treatment with LiCO3 as an adjunct to 131I improves efficacy of RIT in patients with long-lasting GH. A success of RIT achieves faster in lithium-treated than in RI group. Treatment with LiCO3 for 7 days prevents transient worsening of hyperthyroidism after RIT. Short-term use of LiCO3 shows no toxic side effects.

Short term treatment with lithium carbonate as adjunct to radioiodine treatment for long-lasting Graves' hyperthyroidism.

OBJECTIVE: Lithium carbonate is primarily used for the treatment of patients with bipolar affective disorders. Initial treatment of Graves' hyperthyroidism (GHT) with antithyroid drugs (ATD) has limitations at over 50% of treated patients because of significant side effects and relatively high relapses of the disease after drugs withdrawal. Till now, the influence of LiCO3on RIT outcome was mainly studied in patients with recent onset of GHT, and results were contradicted. Meta-analysis of case-control studies showed higher rated hypothyroidism in patients with mood disorders treated with LiCO3(121/869) than in controls (10/578). Although in a small number of patients (n=28) with long-lasting GHT, preliminary results of ours showed that ¹³¹I treatment with LiCO3for 7 days significantly improved the efficacy of RIT versus the non-LiCO3treated patients (P<0.001). Lithium treated patients were cured faster (12 of 13 patients were cured after one month) than those treated only with ¹³¹I (8 patients were cured after one and 11/15 patients after 12 months). Fewer patients treated with ¹³¹I and LiCO3had persistent hyperthyroidism than those treated with ¹³¹I alone. There were no toxic effects of LiCO3during 7 days treatment. CONCLUSION: These observations indicate of that short-term treatment with LiCO3in GHT patients as adjunct to ¹³¹I-NaI improves the efficacy of RIT, prevents transient exacerbation of hyperthyroidism, early induction of hypothyroidism and does not worsen ophthalmopathy.

Thyroid blood flow and uptake of technetium-99m pertechnetate in Graves' disease.

The aim of this study was to assess the relation of early thyroid blood flow (EBF) and technetium-99m pertechnetate ((99m)TcO(-)(4)) uptake, as an early diagnostic index in patients with Graves' disease (GD) by dynamic thyroid scintigraphy (40 frames, 3 sec/frame). Thirty patients with GD with mean age 50.0 +/- 9.0 y, range: 35.0-69.0 y, were studied. The results obtained were compared with those of 30 euthyroid individuals (EI) of mean age 46.9 +/- 12.5 y, range: 22.0-68.0 y. The parameters of (99m)TcO(-)(4) EBF and early uptake studied, derived from the background subtracted time activity curves, were as follows: a) The duration of the EBF in sec; b) The perfusion index (PI) - the ratio of counts at the beginning and at the end of the EBF; c) The uptake index 1 (UI1)- the counts ratio between the counts at the end of the EBF and at the 2nd min d) The uptake index 2 (UI2) - the counts ratio between the 1st min and the 2nd min of the uptake curve and e) Delayed (99m)TcO(-)(4) thyroid uptake (TcTU) at 20 min was also calculated as a percentage of net counts activity accumulated in the thyroid gland at 20 min. Results were as follows: a) The mean values of the duration of the EBF were shorter in GD patients (9.90 +/- 2.94 sec) than in EI (15.70 +/- 4.01 sec; P<0.0001); b) PI did not differ significantly (P>0.05); c) The mean UI1 and UI2 values of thyroid uptake of 99m TcO4- were significantly lower in GD (UI1=0.621, UI2=0.772) as compared to EI (UI1=1.106, UI2=0.947; P<0.0001 for both) and d) TcTU values were significantly higher in GD (13.6%) than in the group of EI (1.29%; P<0.0001). A good correlation was found in patients with GD between early (UI1 and UI2) and delayed TcTU (r = -0.562; P=0.010 and r = -0.459; P=0.042 respectively). Also, in patients with GD the EBF correlated poorly with UI1, UI2 and TcTU (P>0.05 for all these parameters). In conclusion, the results of this study indicate that the duration of EBF did not relate significantly to the height of TcTU values in patients with GD. On the contrary, the early uptake, indices UI1 and especially UI2 were shown to be faster in the majority of GD patients and correlated well with the TcTU. These parameters may be used as diagnostic indices for GD. Further investigation is required to support the above findings.