sodium-perchlorate and Hyperthyroidism

In a prospective, randomized study we examined the influence of prophylactic short-term thyrostatic therapy on thyroid iodine metabolism in patients with euthyroid autonomy undergoing elective coronary angiography. From a total of 1177 patients, 51 fulfilled the criteria of euthyroid autonomy before coronary angiography (negative thyrotropin-releasing hormone test, 10-min uptake of at least 1.2%, 99mTc and no elevation of free thyroxine and free triiodothyronine indices) and were randomized into three groups: group 1 (N = 17) received 20mg/day of thiamazole and group 2 (N = 17) received 900 mg/day of sodium perchlorate; thyrostatic therapy was begun on the day before angiography and continued for 14 days; group 3 (N = 17) served as controls without treatment. Parameters of thyroid function-free thyroxine (FT4) index and free triiodothyronine (FT3) index, thyrotropin (TSH) and delta-TSH urine iodine excretion and 99mTc uptake were determined before and 30 days after coronary angiography. At the end of the study the mean FT4 index and FT3 index were elevated significantly in the control group compared with baseline values, but were still within the normal range. In contrast, the mean FT4 index and FT3 index remained unchanged in the treated groups. Four mild cases of hyperthyroidism were observed at the end of the study: two cases in the control group and one case in each of the treated groups. Thyrotropin suppression, urine iodine excretion and 99mTc uptake differed significantly between the treated groups and the control group. In the treated groups TSH suppression, urine iodine excretion and 99mTC uptake remained unchanged 30 days after coronary angiography compared with baseline values. In the control group the degree of TSH suppression and the level of urine iodine excretion increased (about twofold) significantly after coronary angiography, whereas 99mTc uptake decreased significantly (ca. 50%). In conclusion, short-term prophylactic thyrostatic therapy seems to have a protective effect against iodine excess in patients with euthyroid autonomy. However, mild hyperthyroidism could not be prevented in some cases. Probably a combination therapy of thiamazole and perchlorate would be more effective.

Topics: Aged; Antithyroid Agents; Contrast Media; Coronary Angiography; Female; Humans; Hyperthyroidism; Iodine; Male; Methimazole; Middle Aged; Perchlorates; Pilot Projects; Prospective Studies; Sodium Compounds; Thyroid Function Tests; Thyroid Gland

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

Topics: Amiodarone; Anti-Arrhythmia Agents; Antithyroid Agents; Cardiomyopathies; Cardiopulmonary Resuscitation; Catecholamines; Defibrillators, Implantable; Echocardiography; Electrocardiography; Female; Humans; Hyperthyroidism; Hypokinesia; Methimazole; Middle Aged; Multiple Organ Failure; Perchlorates; Sodium Compounds; Thyroidectomy; Thyrotropin; Ventricular Fibrillation

To evaluate the prevalence of latent and manifest hyperthyroidism in a non-selected group of patients admitted for contrast enhanced CT studies blood samples were tested for the levels of thyroid-stimulating hormone (TSH).. TSH blood levels were obtained in 548 consecutive patients who were scheduled for contrast-enhanced (Iopromide; 300 mg iodine/ml) CT scanning. In case of TSH levels < 0.4 mU/l, blood samples were also tested for triiodothyronine (T3) and tetraiodothyronine (T4) blood levels, and treatment with Irenat (sodium perchlorate) was commenced before scanning. In case of TSH levels < 0.1 mU/l, CT scanning was not performed but further evaluation of the thyroid function was initiated.. TSH blood levels ranged from 0.4 to 7.5 mU/l in 512 patients, and 36 patients (6.6%) had TSH blood levels < 0.4 mU/l and 9 patients blood levels < 0.1 mU/l, with 32 of those patients (5.8%) having regular T3 and T4 blood levels consistent with latent hyperthyroidism. In 4 patients (0.8%), T3 or T4 blood levels were increased consistent with manifest hyperthyroidism.. In South Germany, the prevalence of latent or manifest hyperthyroidism in a non-selected patient group is high. Therefore TSH blood levels should be obtained prior to contrast-enhanced CT studies.

Topics: Adult; Aged; Aged, 80 and over; Contrast Media; Germany; Humans; Hyperthyroidism; Iohexol; Middle Aged; Perchlorates; Prevalence; Sodium Compounds; Thyrotropin; Thyroxine; Tomography, X-Ray Computed; Triiodothyronine

Three patients with subclinical hyperthyroid goitre, women aged 63, 72 and 75 years following intravenous administration of an iodinated contrast medium developed hyperthyroidism with a marked rise of the concentration of free T4. Thyreostatic agents were unsuccessful in two patients, the third was left untreated. Hyperthyroidism improved spontaneously in all three. Iodine-induced hyperthyroidism is rare and is usually encountered in patients with a pre-existent autonomous thyroid function. Treatment of iodine-induced hyperthyroidism is essentially exclusively symptomatic. Prophylaxis with sodium perchlorate should be considered in cardiac patients with a goitre and a subnormal level of thyroid-stimulating hormone (TSH).

Topics: Aged; Antithyroid Agents; Contrast Media; Drug Hypersensitivity; Female; Goiter, Nodular; Humans; Hyperthyroidism; Iodine Compounds; Middle Aged; Perchlorates; Remission, Spontaneous; Sodium Compounds

Topics: Antithyroid Agents; Contrast Media; Dose-Response Relationship, Drug; Drug Administration Schedule; Humans; Hyperthyroidism; Iodine Compounds; Methimazole; Perchlorates; Risk Factors; Sodium Compounds; Thyroid Function Tests

Treatment with the antiarrhythmic agent amiodarone results in alterations in thyroid hormone metabolism, and can induce either hypothyroidism or hyperthyroidism (amiodarone-associated thyrotoxicosis, AAT). AAT occurs in patients both with and without preexisting goiter. In our study of the nongoitrous variety, the effect in vitro of amiodarone treatment and of concurrent treatment with potential inhibitors on thyroid cells (FRTL-5) was assessed by measuring the release of radiolabeled chromium (51Cr). In addition, thyroid histopathology was evaluated in autopsy specimens from six amiodarone-treated patients who had no pretreatment evidence of thyroid disease. Histopathologic examination revealed minimal or no evidence of thyroid follicular damage in specimens from amiodarone-treated euthyroid patients (n = 4). In contrast, moderate to severe follicular damage and disruption were present in glands from patients with AAT (n = 2). Studies in vitro showed amiodarone to be cytotoxic to thyroid cells; this effect was inhibited by treatment with dexamethasone (10(-3) mmol) or perchlorate (2.5 micrograms/mL). In summary, we demonstrate evidence in vitro and in vivo of amiodarone-induced thyroid follicular damage and disruption in specimens from patients with nongoitrous AAT and in cultured normal thyroid cells. In addition, we demonstrate inhibition of this effect following treatment in vitro with dexamethasone or perchlorate. Our findings support the concept that nongoitrous (type I) AAT results from direct drug toxicity with disruption of thyroid follicles and subsequent release of preformed thyroid hormone.

Topics: Adult; Aged; Amiodarone; Cell Line; Chromium Radioisotopes; Cytotoxins; Dexamethasone; Female; Glucocorticoids; Humans; Hyperthyroidism; Male; Middle Aged; Perchlorates; Sodium Compounds; Survival Analysis; Thyroid Gland; Thyrotoxicosis

Topics: Animals; Ascorbic Acid; Glutamates; Glutamic Acid; Hyperthyroidism; Hypothyroidism; Kinetics; Mitochondria, Heart; NAD(P)H Dehydrogenase (Quinone); Oxygen Consumption; Perchlorates; Phospholipids; Rats; Reference Values; Sodium Compounds; Succinates; Triiodothyronine

Coronary angiography (CA) is followed by an iodine load of 15 to 20 mg for the thyroid and may be the cause of iodine-induced hyperthyroidism. 60 consecutive patients hospitalized for CA without any thyroid history were examined and 56 had thyroid diseases with normal thyroid function. 33 patients still showed a significant decrease of 20 min Technetium uptake (TcU) and an increase of urine iodine excretion because of iodine excess 12 weeks after CA. 3 patients developed latent hyperthyroidism. 27 patients received medication of 1 g natrium-perchlorate and 60 mg methimazole 24 hours before and on the day of CA. These patients showed normal TcU and urine iodine excretion 4 and 12 weeks after CA. 1 out of these 27 patients developed overt hyperthyroidism but had PTCA without premedication 2 weeks after CA. Since Iodine excess leads to iodine-induced hyperthyroidism even in euthyroids a prophylaxis with perchlorate and methimazole is generally recommended in patients with CA.

Topics: Adult; Aged; Aged, 80 and over; Contrast Media; Coronary Angiography; Female; Humans; Hyperthyroidism; Iodine; Male; Methimazole; Middle Aged; Perchlorates; Premedication; Sodium Compounds; Thyroid Function Tests

Amiodarone, an iodine-rich drug, represents at the present, at least in Europe, one of the most common sources of iodine-induced thyroid dysfunction. The drug may induce both hypothyroidism and thyrotoxicosis. In spite of the large iodine intake occurring during amiodarone therapy, 131I thyroid uptake is detectable in patients with amiodarone-iodine-induced hypothyroidism, irrespective of the presence or absence of underlying thyroid disease. In contrast, in patients with amiodarone-iodine-induced thyrotoxicosis, 131I thyroid uptake is normal or even elevated in those with co-existent underlying thyroid disorders, whereas it is very low in those with an apparently normal thyroid gland. Perchlorate discharge test was performed in 8 patients with hypothyroidism and in 5 patients with hyperthyroidism induced by amiodarone: a positive test was found in all hypothyroid patients and a negative test in all hyperthyroid patients.

Topics: Adult; Aged; Amiodarone; Female; Humans; Hyperthyroidism; Hypothyroidism; Iodine Radioisotopes; Male; Middle Aged; Perchlorates; Sodium Compounds; Thyroid Function Tests; Thyroid Gland; Thyroid Hormones

Thyroidal binding of iodide was studied by kinetic analysis of [123I]iodide uptake and its discharge by perchlorate in 80 hyperthyroid subjects receiving antithyroid drug therapy. Five dosage regimens ranging from 5 mg carbimazole twice daily to 15 mg methimazole twice daily were studied. Binding inhibition was estimated at 5-7 h after drug as an index of the mean effect of the 12 hourly regimen. In all cases, except one in the lowest dose group, binding was found to be markedly reduced with mean binding rates ranging from 0.002 to 0.020 min-1 (normal greater than 0.15 min-1). The net clearance of iodide in the lowest dose group was reduced to a mean value near the upper limit of the euthyroid range, whereas in the highest dose group it lay at the lower limit of the euthyroid range. These results were reflected in the serum thyroid hormone response. There was a reducing incidence of inadequate control of hyperthyroidism and an increasing incidence of hypothyroidism with increasing thiourylene dose. The exit rate constant of free iodide for the various doses showed values from 0.048 to 0.055 min-1. Corresponding mean values for the discharge rate constant after perchlorate were 0.087 to 0.105 min-1. This suggests that perchlorate increases the rate of iodide release from the thyroid gland. Studies at a later interval after drug (12-14 h) showed no change in discharge rate constant. This leads to the conclusion that perchlorate may further inhibit iodide binding in subjects receiving antithyroid drug therapy.

Topics: Antithyroid Agents; Carbimazole; Dose-Response Relationship, Drug; Humans; Hyperthyroidism; Iodides; Iodine Radioisotopes; Kinetics; Methimazole; Perchlorates; Sodium Compounds; Thyroid Gland; Thyroid Hormones

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: Antithyroid Agents; Carbimazole; Humans; Hyperthyroidism; Iodine Radioisotopes; Methimazole; Perchlorates; Propylthiouracil; Sodium Compounds

The kinetics of [123I]iodide uptake were studied when organification of iodine by the thyroid gland was normal and when this binding function was diminished by drugs or disease. Each study was terminated by a sodium perchlorate discharge test (300--600 mg iv) at 60 min or, in some cases, 10--30 min. The results confirmed that binding takes place rapidly in the uninhibited gland with the binding rate constant being at least 0.150 min-1. Discharge from the uninhibited gland is less than 3.5% of the gland uptake when perchlorate is given 60 min after the radioiodide. Subjects with an intrinsic binding defect manifested discharges of 11% of greater of the 60 min uptake and the estimated binding rate constants ranged from 0.003--0.057 min-1. Thyrotoxic subjects receiving 5 mg carbimazole twice daily manifested discharges ranging from 5.4--64.2%, and in those receiving 20 mg twice daily the observed discharges were 67.6--94.6% of the 60 min uptake. The study shows that a correctly performed perchlorate discharge test will detect minimal inhibition of iodine binding. An important factor is the duration of the follow-up period after perchlorate is given. In some of the cases studied discharge was not complete until 60 min after the perchlorate.

Topics: Binding Sites; Carbimazole; Humans; Hyperthyroidism; Iodine; Perchlorates; Sodium Compounds; Thyroid Gland