sodium-perchlorate and Graves-Disease

The use of iodinated contrast media (ICM) can lead to thyrotoxicosis, especially in patients with risk factors, such as Graves' disease, multinodular goiter, older age, and iodine deficiency. Although hyperthyroidism may have clinically relevant effects, whether high-risk patients should receive prophylactic treatment before they are administered ICM is still debated.. We aimed to demonstrate the safety and efficacy of prophylactic treatment with sodium perchlorate and/or methimazole to prevent ICM-induced hyperthyroidism (ICMIH) in a population of high-risk cardiac patients. We ran a cost analysis to ascertain the most cost-effective prophylactic treatment protocol. We also aimed to identify possible risk factors for the onset of ICMIH.. We performed a longitudinal retrospective study on 61 patients admitted to a tertiary-level cardiology unit for diagnostic and/or therapeutic ICM-procedures. We included patients with available records of thyroid function tests performed before and after ICM were administered, who were at high risk of developing ICMIH. Patients were given one of two different prophylactic treatments (methimazole alone or both methimazole and sodium perchlorate) or no prophylactic treatment. The difference between their thyroid function at the baseline and 11-30 days after the ICM-related procedure was considered the principal endpoint.. Twenty-three (38%) of the 61 patients were given a prophylactic treatment. Thyroid function deteriorated after the administration of ICM in 9/61 patients (15%). These cases were associated with higher plasma creatinine levels at admission, higher baseline TSH levels, lower baseline FT4 levels, and no use of prophylactic treatment. The type of prophylaxis provided did not influence any onset of ICMIH. A cost-benefit analysis showed that prophylactic treatment with methimazole alone was less costly per person than the combination protocol. On multivariate analysis, only the use of a prophylactic treatment was independently associated with a reduction in the risk of ICMIH. Patients not given any prophylactic treatment had a nearly five-fold higher relative risk of developing ICMIH.. Prophylactic treatment can prevent the onset of ICMIH in high-risk populations administered ICM. Prophylaxis is safe and effective in this setting, especially in cardiopathic patients. Prophylaxis with methimazole alone seems to be the most cost-effective option.

Topics: Contrast Media; Graves Disease; Humans; Hyperthyroidism; Methimazole; Retrospective Studies; Risk Factors

The transport of iodide into the thyroid, catalyzed by the Na+/I- symporter (NIS), is the initial and rate-limiting step in the formation of thyroid hormones. To study the basic characteristics of the human (h) NIS, we have established a Chinese hamster ovary cell line stably expressing the hNIS (CHO-NIS9). In agreement with previous work on the rat NIS, iodide uptake in these cells was initiated within 2 min of the addition of 131I, reaching a plateau after 30 min. Both perchlorate and thiocyanate inhibited iodide uptake in a dose-dependent manner, with inhibition evident at concentrations of 0.01 and 0.1 micromol/L, respectively, and reaching complete inhibition at 20 micromol/L and 500 micromol/L, respectively. Ouabain, which blocks the activity of the Na+/K+ adenosine triphosphatase, also inhibited iodide uptake in a dose-dependent manner, starting at concentrations of 100 micromol/L and reaching maximum inhibition at 1600 micromol/L, indicating that iodide uptake in these cells is sodium dependent. CHO-NIS9 cells were further used to study 88 sera from patients with Graves' disease, for iodide uptake inhibitory activity, which were compared with sera from 31 controls. Significant iodide uptake inhibition was taken as any inhibition in excess of the mean + 3 SD of the results with the control sera. On this basis, 27 (30.7%) of the Graves' sera, but none of the controls, inhibited iodide uptake in CHO-NIS9. IgGs from these patients also inhibited iodide uptake, indicating that this inhibitory activity was antibody mediated. In summary, we have established a CHO cell line stably expressing the hNIS and shown that antibodies in GD sera can inhibit iodide uptake in these cells. This further emphasizes the role of NIS as a novel autoantigen in thyroid immunity.

Topics: Animals; Antibodies; Carrier Proteins; Case-Control Studies; CHO Cells; Cricetinae; Graves Disease; Humans; Iodides; Membrane Proteins; Ouabain; Perchlorates; Recombinant Proteins; Sodium Compounds; Symporters; Thiocyanates; Transfection

Nine patients with hyperthyroidism due to Graves' disease did not respond to therapy with very large doses (800 to 2000 mg/d) of propylthiouracil. In eight patients, studies showed propylthiouracil was absorbed and metabolized normally. Five patients had no detectable propylthiouracil in their serum 2 to 3 hours after supposedly taking their medication at home, and three patients had markedly abnormal results of perchlorate discharge tests after receiving propylthiouracil under supervision. After evaluation, noncompliance was thought to be the reason for treatment failure in six of the nine patients; one patient was possibly resistant. In two patients, data were insufficient, although intermittent noncompliance could not be ruled out. Among patients who respond poorly to propylthiouracil therapy, noncompliance is the most likely reason. In such patients, methimazole should be substituted for continued massive doses of propylthiouracil.

Topics: Adolescent; Adult; Drug Resistance; Female; Graves Disease; Humans; Hyperthyroidism; Iodides; Male; Middle Aged; Patient Compliance; Perchlorates; Pregnancy; Propylthiouracil; Sodium Compounds; Thyroxine

Topics: Graves Disease; Humans; Immunosuppressive Agents; Perchlorates; Receptors, Cell Surface; Receptors, Thyrotropin; Sodium Compounds