The influence of thionamides on intra-thyroidal uptake of 131I during radioiodine-131 treatment of Graves' disease

Graves' disease is one of the most common causes of hyperthyroidism. Guideline recommendations advocate the intake of thionamides for at least 1 year. If hyperthyroidism persists, subsequent radioiodine-131 treatment (RIT) is a therapeutic option. Thionamides are known to influence intra-thyroidal bio-kinetics of iodine and should therefore be discontinued at least 3 days prior to RIT if possible. However, the required therapeutic activity has to be calculated individually by pre-therapeutic measurement of the uptake prior to RIT [radioiodine-131 uptake test (RIUT)] in Germany according to national guidelines. Therefore, the aim of this study was to quantify the influence of thionamides on intra-therapeutic uptake. A cohort of 829 patients with Graves' disease undergoing RIUT and RIT was analysed. Patients were subdivided into three groups. Group A: patients with carbimazole medication (n = 312), group B: patients with methimazole medication (n = 252) and group C: patients without thionamides (n = 265). Group A and B were further subdivided depending on the reduction of dosage of thionamides. In order to analyse the influence of thionamides, the variance of the determined individual extrapolated maximum intra-thyroidal uptake (EMU) between RIUT and RIT within the single groups and within the subgroups was statistically evaluated. When administering an equal dose of thionamides or no thionamides in RIUT and RIT (groups A1, B1 and C) no significant differences were detected when comparing EMU in RIT to EMU in RIUT (p > 0.05). In the subgroups A2-A4 (reduced dosage of carbimazole prior to RIT) EMU was significantly increased in RIT compared to RIUT [21% for a reduction of 0 to < 10 mg/d (A2), 39% for a reduction of 10-15 mg/d (A3) and 80% for a reduction of > 15 mg/d (A4)]. In the subgroups B2-B4 (reduced dosage of methimazole prior to RIT) EMU was as well significantly increased in RIT compared to RIUT [26% for a reduction of 0 to < 10 mg/d (B2), 36% for a reduction of 10-15 mg/d (B3) and 59% for a reduction of > 15 mg/d (B4)]. A significant dose-dependent increase of EMU in RIT compared to EMU in RIUT in patients discontinuing or reducing thionamides was detected. Therefore, thionamides should be discontinued at least 2 days prior to RIUT in order to achieve the designated target dose more precisely and to minimize radiation exposure of organs at risk.

Brain functional connectivity in patients with hyperthyroidism after anti-thyroid treatment

Thyroid disease is known to affect brain metabolism and cognitive function, although the recovery of thyroid-induced brain functional changes after treatment remains unclear. We aimed to investigate the alteration in brain functional connectivity and its correlation with neuropsychological variables in hyperthyroid patients before and after anti-thyroid treatment using a resting-state functional magnetic resonance imaging (rsfMRI) technique. This is a follow-up rsfMRI study of previous work that showed impaired brain functional connectivity in hyperthyroid patients compared to healthy controls. We included rsfMRI and neuropsychological data from 21 hyperthyroid patients out of an original cohort of 28 patients, before and after anti-thyroid treatment for 30 weeks. Functional connectivity analysis and neuropsychological scores were compared using paired t tests in patients at baseline and at follow-up. Patients showed an improvement in some of the memory (p < .05) and executive, visuospatial and motor (p < .001) functions after treatment, and also showed increased functional connectivity in the regions of the right fronto-parietal network, left fronto-parietal network, and default mode network (DMN) (p < .05). At follow-up, the functional connectivity of the right fronto-parietal network showed a significantly positive correlation with the recognition of objects memory score. The overall findings suggest that anti-thyroid treatment with carbimazole improves the functional connectivity within some of the resting state networks in the hyperthyroid patients, whereas the remaining networks still show impairment.

Graves' disease associated with cholestatic jaundice and persistent diarrhoea

Liver involvement in Graves' disease can be seen as a part of autoimmune process or rarely, due to the direct effects of thyrotoxicosis on liver. Hyperthyroidism can also have gastrointestinal manifestations like frequent bowel movements, diarrhoea, even malabsorption with steatorrhoea. We report a 36-year-old man with hyperthyroidism, presenting with cholestatic jaundice and persistent small bowel diarrhoea. He was diagnosed to have Graves' disease and after ruling out more common causes, the cause of cholestatic jaundice was supposed to be Graves' disease. Considering this possibility, the patient was started on treatment with carbimazole. As patient's thyroid function tests started improving, he showed significant clinical and biochemical improvement from liver point of view as well.

Metabolic effects of brown fat in transitioning from hyperthyroidism to euthyroidism

OBJECTIVE

Brown adipose tissue (BAT) controls metabolic rate through thermogenesis. As its regulatory factors during the transition from hyperthyroidism to euthyroidism are not well established, our study investigated the relationships between supraclavicular brown adipose tissue (sBAT) activity and physiological/metabolic changes with changes in thyroid status.

DESIGN

Participants with newly diagnosed Graves' disease were recruited. A thionamide antithyroid drug (ATD) such as carbimazole (CMZ) or thiamazole (TMZ) was prescribed in every case. All underwent energy expenditure (EE) measurement and supraclavicular infrared thermography (IRT) within a chamber calorimeter, as well as 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography/magnetic resonance (PET/MR) imaging scanning, with clinical and biochemical parameters measured during hyperthyroidism and repeated in early euthyroidism. PET sBAT mean/maximum standardized uptake value (SUV mean/max), MR supraclavicular fat fraction (sFF) and mean temperature (Tscv) quantified sBAT activity.

RESULTS

Twenty-one (16 female/5 male) participants aged 39.5 ± 2.5 years completed the study. The average duration to attain euthyroidism was 28.6 ± 2.3 weeks. Eight participants were BAT-positive while 13 were BAT-negative. sFF increased with euthyroidism (72.3 ± 1.4% to 76.8 ± 1.4%; P < 0.01), but no changes were observed in PET SUV mean and Tscv. Significant changes in serum-free triiodothyronine (FT3) levels were related to BAT status (interaction P value = 0.04). FT3 concentration at hyperthyroid state was positively associated with sBAT PET SUV mean (r = 0.58, P = 0.01) and resting metabolic rate (RMR) (P < 0.01).

CONCLUSION

Hyperthyroidism does not consistently lead to a detectable increase in BAT activity. FT3 reduction during the transition to euthyroidism correlated with BAT activity.

Graves' disease presenting with hypomania and paranoia to the acute psychiatry service

This manuscript describes the case of a young woman, with no prior psychiatric history, who developed hypomania and paranoia as the principal presenting features of Graves' disease. After starting treatment with carbimazole and propranolol, symptoms resolved without the use of antipsychotic drugs. Close liaison between psychiatry and endocrinology services was essential. This demonstrates that treating underlying thyrotoxicosis in patients presenting with psychiatric symptoms may lead to recovery without the use of antipsychotic medication. While agitation, irritability and mood lability are well-recognised thyrotoxic symptoms, psychosis is a rare presenting feature of Graves' disease. All patients with agitation, delirium or psychiatric symptoms should have thyroid function checked as part of initial tests screening for organic disease. In new or relapsing psychiatric conditions, it is important to ask patients, their carers or relatives about symptoms of hypothyroidism or thyrotoxicosis.

Hyperthyroidism in Cats: Considering the Impact of Treatment Modality on Quality of Life for Cats and Their Owners

In cats, hyperthyroidism can be treated in 4 ways: medical management with methimazole or carbimazole, nutritional management (low-iodine diet), surgical thyroidectomy, and radioactive iodine (¹³¹I). Each form of treatment has advantages and disadvantages that should be considered when formulating a treatment plan for the individual hyperthyroid cat. Medical and nutritional managements are considered "reversible" or palliative treatments, whereas surgical thyroidectomy and ¹³¹I are "permanent" or curative treatments. The author discusses how each treatment modality could be the optimal choice for a specific cat-owner combination and reviews the advantages and disadvantages of each treatment option.

Thyrotoxic Periodic Paralysis with Hypokalemia in an Adult Male from Nepal: A Case Report

Thyrotoxic periodic paralysis is rare complication of hyperthyroidism characterized by the sudden onset of hypokalemia and muscle paralysis. It is typically present in young Asian males. There are very few literatures regarding the occurrence of thyrotoxic hypokalemic periodic paralysis in Nepal. We reported a case of a 35-year-old male presented with the chief complaints of weakness of all four limbs of 1 day duration. He was diagnosed as a case of hyperthyroidism in the past, received treatment for 6 months and left medications on his own 6 months ago. Evaluation during admission revealed severe hypokalemia with serum potassium level 1.3mEq/l and high serum Triiodothyronine (>20.00µg/L) and low serum Thyroid Stimulating Hormone (<0.01µg/L). Potassium supplements resolved muscle weakness and the patient was restarted with anti-thyroid drugs. Hence, hypokalemic paralysis is a reversible cause of paralysis and high index of suspicion as well as timely interventions are required to prevent potential harm.

Thyrotrophin receptor antibody concentration and activity, several years after treatment for Graves' disease

OBJECTIVE

TSH receptor antibodies (TRAb) are responsible for autoimmune hyperthyroid disease (Graves' disease; GD) with TRAb levels tending to decrease following treatment. Measurement of TRAb activity during follow-up could prove valuable to better understand treatment effectiveness.

STUDY DESIGN

TRAb concentration and stimulating (TSAb) and blocking (TSBAb) activity of patient serum were assessed following different treatment modalities and follow-up length.

METHODS

Sixty-six subjects were recruited following treatment with carbimazole (n = 26), radioiodine (n = 27) or surgery (n = 13). TRAb, TPOAb, TgAb and GADAb were measured at a follow-up visit as well as bioassays of TSAb and TSBAb activity.

RESULTS

Forty-five per cent of all patients remained TRAb-positive for more than one year and 23% for more than 5 years after diagnosis, irrespective of treatment method. Overall, TRAb concentration fell from a median (IQR) of 6.25 (3.9-12.7) to 0.65 (0.38-3.2) U/L. Surgery conferred the largest fall in TRAb concentration from 11.4 (6.7-29) to 0.58 (0.4-1.4) U/L. Seventy per cent of TRAb-positive patients were positive for TSAb, and one patient (3%) was positive for TSBAb. TRAb and TSAb correlated well (r = 0.83). In addition, 38/66 patients were TgAb-positive, 47/66 were TPOAb-positive and 6/66 were GADAb-positive at follow-up.

CONCLUSIONS

TRAb levels generally decreased after treatment but persisted for over 5 years in some patients. TRAb activity was predominantly stimulatory, with only one patient demonstrating TSBAb. A large proportion of patients were TgAb/TPOAb-positive at follow-up. All treatment modalities reduced TRAb concentrations; however, surgery was most effective.

Difficultés de prise en charge de la maladie de Basedow chez l’enfant : à propos d’un cas

La prise en charge adéquate de la maladie de Basedow chez l'enfant reste un sujet de controverse en endocrinologie pédiatrique et la durée optimale du traitement médical pour induire une rémission de la maladie ainsi que les indications des thérapeutiques alternatives, restent à définir. Nous rapportons l'observation d'une enfant âgée de 11 ans, sans antécédents pathologiques particuliers, qui consulte pour un amaigrissement progressif associé à des diarrhées. C'est devant la survenue d'une tuméfaction cervicale antérieure constatée par l'entourage que les parents décident de consulter. Les données cliniques et paracliniques ont permis de retenir le diagnostic de la maladie de Basedow. La patiente a été mise sous traitement médical : Carbimazole. L'évolution a été marquée par l'apparition d'une thrombopénie suggérant une administration prudente du traitement médical et devant l'absence de rémission après 4 ans de traitement, une irathérapie a été indiquée. Bien que rare, la maladie de Basedow reste la première cause de l'hyperthyroïdie chez l'enfant. Son diagnostic positif est facile mais sa prise en charge peut poser d'énormes problèmes. Le traitement médical se base sur les antithyroïdiens de synthèse mais qui n'est pas toujours anodin comme pour le cas de notre patiente .la thyroïdectomie subtotale ou le traitement par iode radioactif sont les deux alternatives thérapeutiques. De diagnostic positif facile, la maladie de Basedow est une maladie rare et sévère chez l'enfant et qui pose surtout des difficultés de prise en charge.

Refractory hepatic encephalopathy in a patient with hypothyroidism: Another element in ammonia metabolism

Hepatic encephalopathy (HE) remains a diagnosis of exclusion due to the lack of specific signs and symptoms. Refractory HE is an uncommon but serious condition that requires the search of hidden precipitating events (i.e., portosystemic shunt) and alternative diagnosis. Hypothyroidism shares clinical manifestations with HE and is usually considered within the differential diagnosis of HE. Here, we describe a patient with refractory HE who presented a large portosystemic shunt and post-ablative hypothyroidism. Her cognitive impairment, hyperammonaemia, electroencephalograph alterations, impaired neuropsychological performance, and magnetic resonance imaging and spectroscopy disturbances were highly suggestive of HE, paralleled the course of hypothyroidism and normalized after thyroid hormone replacement. There was no need for intervention over the portosystemic shunt. The case findings support that hypothyroidism may precipitate HE in cirrhotic patients by inducing hyperammonaemia and/or enhancing ammonia brain toxicity. This case led us to consider hypothyroidism not only in the differential diagnosis but also as a precipitating factor of HE.

Physiological and Metabolic Changes During the Transition from Hyperthyroidism to Euthyroidism in Graves' Disease

BACKGROUND

The serum metabolomic profile and its relationship to physiological changes during hyperthyroidism and restoration to euthyroidism are not known. This study aimed to examine the physiological, adipokine, and metabolomic changes that occur when subjects with Graves' disease transition from hyperthyroidism to euthyroidism with medical treatment.

METHODS

Chinese women between 21 and 50 years of age and with newly diagnosed Graves' disease attending the endocrine outpatient clinics in a single institution were recruited between July 2012 and September 2014. All subjects were treated with thioamides to achieve euthyroidism. Clinical parameters (body weight, body composition via bioelectrical impedance analysis, resting energy expenditure and respiratory quotient via indirect calorimetry, and reported total energy intake via 24 h food diary), biochemical parameters (thyroid hormones, lipid profile, fasting insulin and glucose levels), serum leptin, adiponectin, and metabolomics profiles were measured during hyperthyroidism and repeated in early euthyroidism.

RESULTS

Twenty four Chinese women with an average age of 36.3 ± 8.6 years were included in the study. The average duration of treatment that was required to reach euthyroidism for these subjects was 38 ± 16.3 weeks. There was a significant increase in body weight (52.6 ± 9.0 kg to 55.3 ± 9.4 kg; p < 0.001) and fat mass (14.3 ± 6.9 kg to 16.8 ± 6.5 kg; p = 0.005). There was a reduction in resting energy expenditure corrected for weight (28.7 ± 4.0 kcal/kg to 21.5 ± 4.1 kcal/kg; p < 0.001) and an increase in respiratory quotient (0.76 to 0.81; p = 0.037). Resting energy expenditure increased significantly with increasing free triiodothyronine levels (p = 0.007). Significant increases in total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were noted. There was no significant change in leptin levels, but adiponectin levels increased significantly (p = 0.018). Significant reductions in fasting C2, medium-chain, long-chain, and total acylcarnitines were observed, but no changes in the fat-free mass, branched chain amino acid levels, or insulin sensitivity during recovery from hyperthyroidism were noted.

CONCLUSIONS

Serum metabolomics profile changes complemented the physiological changes observed during the transition from hyperthyroidism to euthyroidism. This study provides a comprehensive and integrated view of the changes in fuel metabolism and energy balance that occur following the treatment of hyperthyroidism.

The effect of thyroid dysfunction on N-terminal pro-B-type natriuretic peptide concentrations

Background: B-type natriuretic peptides and N-terminal pro-B-type natriuretic peptides (NT-proBNP) have been suggested as being useful for the diagnosis of congestive heart failure. We have shown previously that changes in thyroid function are associated with changes in concentrations of other low molecular weight molecules. Therefore, the aim of this study was to assess whether similar changes occurred with NT-proBNP concentrations following treatment of thyroid dysfunction.

Methods: Seventeen patients (12 female, 5 male, age range 24-77 years) with newly diagnosed hypothyroidism and 21 patients (16 female, 5 male, age range 21-66 years) with newly diagnosed hyperthyroidism had NT-proBNP measured at baseline and when they subsequently became euthyroid.

Results: NT-proBNP levels were not significantly different in the hyperthyroid group from the hypothyroid, either before ( P = 0.706) or after treatment to euthyroidism ( P = 0.170). The hypothyroid group showed a rise in NT-proBNP after treatment ( P < 0.001). There was a marginally significant fall in the NT-proBNP levels in the hyperthyroid group ( P = 0.05). However, these changes were within the expected wide range of biological variability of NT-proBNP shown in earlier studies.

Conclusions: Hypothyroidism alters NT-proBNP concentrations, but the magnitude of this effect may be lost in the wide biological variability of natriuretic peptides and this statistically significant finding is not likely to be of clinical relevance.

Thyrotropin Receptor Antibody Levels at Diagnosis and After Thionamide Course Predict Graves' Disease Relapse

BACKGROUND

Thionamides are associated with a high risk of recurrence following cessation. Thyrotropin receptor-stimulating antibody (TRAb) levels at diagnosis and/or after thionamides may be biomarkers of this risk. This study assesses the natural history of Graves' thyrotoxicosis following thionamide withdrawal and factors that predict recurrence, particularly TRAb levels at diagnosis and cessation.

METHODS

An observational study was conducted of patients with a first presentation of Graves' disease, who were prescribed (and completed) a course of primary thionamide treatment (n = 266) in a university teaching hospital endocrine clinic. Recurrence rates over four years and factors predictive of recurrent thyrotoxicosis were assessed.

RESULTS

The relapse rate was 31% at one year and 70% at four years. Younger age (39 years [range 30-49 years] vs. 47 years [range 37-53 years]; p = 0.011), higher TRAb levels at diagnosis (8.8 IU/L [range 5.3-17.0 IU/L] vs. 5.7 IU/L [range 4.1-9.1 IU/L]; p = 0.003), and higher TRAb levels at cessation of therapy (1.2 IU/L [range 0-2.3 IU/L] vs. <0.9 IU/L [range 0-1.3 IU/L]; p = 0.003) were associated with a higher risk of relapse. By four years, cessation TRAb <0.9 IU/L was associated with a 58% risk of recurrence compared with 82% with TRAb >1.5 IU/L (p = 0.001). TRAb at diagnosis >12 IU/L was associated with an 84% risk of recurrence over four years compared with 57% with TRAbs <5 IU/L (p = 0.002).

CONCLUSION

High TRAb at diagnosis and/or positive TRAb at cessation of therapy suggest a high likelihood of relapse, mostly within the first two years. They stratify patients likely to need definitive therapy (radioiodine or surgery).

Fetal Hyperthyroidism: Intrauterine Treatment with Carbimazole in Two Siblings

Hyperthyroidism can manifest very early in fetal life (fetal thyrotoxicosis) or immediately after birth (neonatal thyrotoxicosis). The authors describe outcome of pregnancies in a woman with Graves' disease who received medical management and underwent subtotal thyroidectomy. The first pregnancy resulted in macerated stillbirth at 32 wk. Fetal tachycardia was followed by intrauterine death at 30 wk in the second pregnancy and macerated stillbirth at 26 wk in the third pregnancy. Fetal tachycardia was detected at 17 wk in the fourth pregnancy. Treatment with carbimazole along with thyroxine was followed by a live birth at 35 wk; but the baby developed severe fatal neonatal thyrotoxicosis with crisis on day 9 and died on day 12. Fetal tachycardia was noted in the fifth pregnancy as well and she was treated with carbimazole and thyroxine. She delivered a male baby at 37 wk. He developed neonatal hypothyroidism on day 8 which was controlled with thyroxine.

Should radioiodine be the first-line treatment for paediatric Graves' disease?

BACKGROUND

Debate exists regarding the optimal treatment strategy for paediatric Graves' disease with radioiodine (RAI), and surgery, usually reserved for failure of medical therapy. We present our own experience to introduce a review of the published literature focussing on the predictors of remission after antithyroid drug (ATD) therapy from diagnosis, and discuss whether RAI should be considered as a first-line therapy.

METHOD

A retrospective analysis of all diagnosed cases of paediatric Graves' disease presenting to a large District General Hospital.

RESULTS

Thirteen patients were diagnosed with Graves' disease between February 2004 and May 2013. The median age at diagnosis was 13.7 years (range 7.2-17.1 years) with a female:male ratio of 11:2. Some nine patients completed a 2-year course of carbimazole out of which 8 relapsed after a mean duration of 0.82 years (range 0.08-1.42 years); the ninth currently remains in remission. Of the eight patients who relapsed, three have undergone RAI treatment. Two patients failed to tolerate carbimazole treatment, one of whom received RAI treatment because surgery was contraindicated and one patient with severe autism proceeded to RAI treatment due to poor compliance and persistent hyperthyroidism.

LITERATURE REVIEW

Prognostic factors at presentation predicting a low likelihood of remission following ATD treatment include younger age, non-Caucasian ethnicity, and severe clinical and/or biochemical markers of hyperthyroidism. Psycho-social factors including compliance also influence management decisions.

CONCLUSION

In specifically selected patients presenting with paediatric Graves' disease, the benefits and risks of radioactive iodine as a potential first-line therapy should be communicated allowing families to make informed decisions.

Antithyroid drug-related hepatotoxicity in hyperthyroidism patients: a population-based cohort study

AIMS

The evidence of hepatotoxicity of antithyroid drugs (ATDs) is limited to case reports or spontaneous reporting. This study aimed to quantify the incidence and comparative risks of hepatotoxicity for methimazole (MMI)/carbimazole (CBM) vs. propylthiouracil (PTU) in a population-based manner.

METHODS

We conducted a cohort study of hyperthyroidism patients initially receiving MMI/CBM or PTU between 1 January 2004 and 31 December 2008 using the Taiwan National Health Insurance Research Database. The examined hepatotoxicity consisted of cholestasis, non-infectious hepatitis, acute liver failure and liver transplant, with the incidences and relative risks being quantified by Poisson exact methods and Cox proportional hazard models, respectively.

RESULTS

The study cohort comprised 71 379 ATD initiators, with a median follow-up of 196 days. MMI/CBM vs. PTU users had a higher hepatitis incidence rate (3.17/1000 vs. 1.19/1000 person-years) but a lower incidence of acute liver failure (0.32/1000 vs. 0.68/1000 person-years). The relative risk analysis indicated that any use of MMI/CBM was associated with a 2.89-fold (95% CI 1.81, 4.60) increased hepatitis risk compared with PTU, with the risk increasing to 5.08-fold for high dose MMI/CBM (95% CI 3.15, 8.18). However, any MMI/CBM use vs. PTU was not related to an increased risk of cholestasis (adjusted hazard ratio [HR] 1.14, 95% CI 0.40, 3.72) or acute liver failure (adjusted HR 0.54, 95% CI 0.24, 1.22).

CONCLUSIONS

MMI/CBM and PTU exert dissimilar incidence rates of hepatotoxicity. Compared to PTU, MMI/CBM are associated in a dose-dependent manner with an increased risk for hepatitis while the risks are similar for acute liver failure and cholestasis.

Congenital anomalies in children exposed to antithyroid drugs in-utero: a meta-analysis of cohort studies

Background

Hyperthyroidism affects about 0.2%-2.7% of all pregnancies, and is commonly managed with antithyroid drugs (ATDs). However, previous studies about the effects of ATDs on congenital anomalies are controversial. Therefore, the present meta-analysis was performed to explore the risk of congenital anomalies in children exposed to ATDs in-utero.

Methods

Embase, Pubmed, Web of Knowledge, and BIOSIS Citation Index were searched to find out studies about congenital anomalies in children exposed to ATDs in-utero reported up to May 2014. The references cited by the retrieved articles were also searched. The relative risks (RRs) and confidence intervals (CIs) for the individual studies were pooled by fixed effects models, and heterogeneity was analyzed by chi-square and I² tests.

Results

Eight studies met the inclusion criteria. Exposure to propylthiouracil (PTU), methimazole/carbimazole (MMI/CMZ), and PTU & MMI/CMZ was investigated in 7, 7 and 2 studies, respectively. The pooled RR was 1.20 (95%CI: 1.02-1.42), 1.64 (95%CI: 1.39-1.92), and 1.83 (95%CI: 1.30-2.56) for congenital anomalies after exposure to PTU, MMI/CMZ, and PTU & MMI/CMZ, respectively.

Conclusions

The meta-analysis suggests that exposure to ATDs in-utero increases the risk of congenital anomalies. The use of ATDs in pregnancy should be limited when possible. Further research is needed to delineate the exact teratogenic risk for particular congenital anomaly.

The dangers of iodine-based contrasts in an elderly patient with thyroid disease

Iodine-based contrast agents are widely used in angiographic and other radiological procedures. Clinicians are familiar with many of the potential adverse events from contrast agents including allergic reactions and contrast-induced nephropathy. This case describes a lesser known adverse event: 'contrast-induced thyrotoxicosis' and its implications on the presentation and management of a patient with severe coronary artery disease. The management of this case was difficult and required a long inpatient admission with use of prednisolone, propylthiouracil and planned treatment with radioiodine to control the thyrotoxicosis, as well as the use of several rate-limiting agents and antianginal medications to control atrial fibrillation and prevent further episodes of angina.

Therapy of endocrine disease: antithyroid drug use in early pregnancy and birth defects: time windows of relative safety and high risk?

BACKGROUND

Antithyroid drugs (ATDs) may have teratogenic effects when used in early pregnancy.

OBJECTIVE

To review the association between the time period of ATD exposure in early pregnancy and the development of birth defects.

METHODS

We identified publications on birth defects after early pregnancy exposure to the ATDs methimazole (MMI; and its prodrug carbimazole (CMZ)) and propylthiouracil (PTU). Cases of birth defects after ATD treatment had been initiated or terminated within the first 10 weeks of pregnancy were identified and studied in detail.

RESULTS

A total of 92 publications were read in detail. Two recent large controlled studies showed ATD-associated birth defects in 2-3% of exposed children, and MMI/CMZ-associated defects were often severe. Out of the total number of publications, 17 included cases of birth defects with early pregnancy stop/start of ATD treatment, and these cases suggested that the high risk was confined to gestational weeks 6-10, which is the major period of organogenesis. Thus, the cases reported suggest that the risk of birth defects could be minimized if pregnant women terminate ATD intake before gestational week 6.

CONCLUSION

Both MMI and PTU use in early pregnancy may lead to birth defects in 2-3% of the exposed children. MMI-associated defects are often severe. Proposals are given on how to minimize the risk of birth defects in fertile women treated for hyperthyroidism with ATDs.

[Thyrostatic treatment and its adverse effects]

Antithyroid drugs are relatively simple molecules known as thionamides, which contain a sulfhydryl group and a thiourea moiety within a heterocyclic structure. Propylthiouracil (6- propyl 2- sulfanylidene 1,2,3,4- tetrahydropyrimidin4- one) and methimazole (1- metyl 2,3- dihydro1H imidazole 2- thione) are the antithyroid drugs used in the United States. Methimazole is used in most of Europe and Asia, and carbimazole -  methimazole analogue, is used in the United Kingdom and parts of the former British Commonwealth. Their primary effect is to inhibit thyroid hormone synthesis by interfering with thyroid peroxidase mediated iodination of tyrosine residues in thyroglobulin and is an important step in the synthesis of thyroxine and triiodothyronine. Propylthiouracil (but not methimazole or carbimazole), can block the conversion of thyroxine to triiodothyronine within the thyroid and in peripheral tissues. Antithyroid drugs may have clinically important immunosuppressive effects. Side effects of thionamides are usually mild, serious untoward effects are observed in < 5% of cases, more frequently during the initial phases of treatment, when the drug daily dose is higher.

Speech and language delay in two children: an unusual presentation of hyperthyroidism

BACKGROUND

Hyperthyroidism is rare in pre-school children. Untreated, it can have a profound effect on normal growth and development, particularly in the first 2 years of life. Although neurological manifestations of dysthyroid states are well known, specific expressive speech and language disorder as a presentation of hyperthyroidism is rarely documented.

METHODS

Case reports of two children with hyperthyroidism presenting with speech and language delay.

RESULTS

We report two pre-school children with hyperthyroidism, who presented with expressive speech and language delay, and demonstrated a significant improvement in their language skills following treatment with anti-thyroid medication.

CONCLUSIONS

Hyperthyroidism must be considered in all children presenting with speech and language difficulties, particularly expressive speech delay. Prompt recognition and early treatment are likely to improve outcome.

Evaluating and managing patients with thyrotoxicosis

BACKGROUND

Thyrotoxicosis is common in the Australian community and is frequently encountered in general practice. Graves disease, toxic multinodular goitre, toxic adenoma and thyroiditis account for most presentations of thyrotoxicosis.

OBJECTIVE

This article outlines the clinical presentation and evaluation of a patient with thyrotoxicosis. Management of Graves disease, the most frequent cause of thyrotoxicosis, is discussed in further detail.

DISCUSSION

The classic clinical manifestations of thyrotoxicosis are often easily recognised by general practitioners. However, the presenting symptoms of thyrotoxicosis are varied, with atypical presentations common in the elderly. Following biochemical confirmation of thyrotoxicosis, a radionuclide thyroid scan is the most useful investigation in diagnosing the underlying cause. The selection of treatment differs according to the cause of thyrotoxicosis and the wishes of the individual patient. The preferred treatment for Graves disease is usually antithyroid drug therapy, almost always carbimazole. The primary treatment of a toxic multinodular goitre or toxic adenoma is usually radioactive iodine therapy. Specific therapy is usually not warranted in cases of thyroiditis, however, treatment directed at symptoms may be required. Referral to an endocrinologist is recommended if thyroiditis is unlikely or has been excluded.

C-type natriuretic peptide forms in adult hyperthyroidism: correlation with thyroid hormones and markers of bone turnover

CONTEXT

Plasma C-type natriuretic peptide (CNP) forms correlate with linear growth velocity in juveniles. In hyperthyroid children, plasma CNP products fall in parallel with height velocity and thyroid hormones (TH) as euthyroidism is restored. The effect of TH on CNP forms after completion of endochondral growth is unknown.

OBJECTIVE

To determine the effect of restoring euthyroidism on plasma CNP forms and bone turnover markers (BTMs) in hyperthyroid adults.

DESIGN AND SETTING

We performed a prospective observational study in 20 adults (19 women) with acquired hyperthyroidism before and during carbimazole treatment. INTERVENTION AND MAIN OUTCOMES: Blood levels of CNP, amino-terminal propeptide of CNP (NTproCNP), TH and BTMs - bone-specific alkaline phosphatase, osteocalcin, procollagen type 1 amino-terminal propeptide and type 1 collagen C-telopeptide (CTx) - were measured before and during the first 6 months of carbimazole treatment and correlations determined.

RESULTS

Both CNP and NTproCNP were significantly correlated with TH at baseline. As in children, decreases in CNP forms were closely associated with fall in TH. Significant associations were found between CNP forms and CTx.

CONCLUSIONS

CNP production from tissues other than endochondral cartilage is responsive to TH. Strong temporal links with markers of bone resorption suggest that CNP may also participate in bone remodelling in the adult skeleton.

Coronary artery spasm due to thyrotoxicosis

A 50-year-old lady presented with chest pain, tremor, weight loss and intermittent ST elevation in her ECG associated with elevated markers of myocardial injury. She was diagnosed with Graves' disease and coronary angiogram showed normal coronary arteries. It was felt coronary artery spasm secondary to thyrotoxicosis was the cause for her ECG changes and pain. She was successfully treated with diltiazem, metoprolol and carbimazole. This case highlights the importance of considering hyperthyroidism in the diagnosis of chest pain with normal coronary arteries.

Bone mineral density trends in Indian patients with hyperthyroidism--effect of antithyroid therapy

BACKGROUND

Hyperthyroidism is associated with bone loss, which is reversible after treatment. The extent of reversibility of loss of bone mass density (BMD) in hyperthyroid patients after treatment especially at forearm is not clear. Therefore, the present study was conducted to assess degree of reversibility in bone mineral density following one-year medical treatment in Indian patients with hyperthyroidism.

METHODS

A total of 30 consecutive patients with hyperthyroidism were included in this one year study at All India Institute of Medical Sciences, New Delhi, India. All the patients were assessed for parameters of bone mineral homeostasis such as calcium, phosphorous, alkaline phosphatase, 25-hydroxy vitamin D [25 (OH) D], parathyroid hormone (PTH) at the time of diagnosis and after one year medical treatment. Bone mineral density was measured using Hologic DXA scan at hip, spine and forearm. All the patients received medical therapy with carbimazole. The parameters of bone homeostasis and bone mineral density at base line and after one year medical treatment was compared.

RESULTS

All patients attained euthyroid status after eight weeks of carbimazole therapy. Parameters of bone homeostasis such as calcium, phosphorous, 25 (OH) D and PTH did not show any significant change from base line. Bone mineral density expressed as bone mineral content in gm/cm2 at left hip neck, trochanteric and intertrochanteric region was significantly higher after carbimazole therapy (745.2 +/- 127.6 gm/cm2 vs. 688.2 +/- 123.5 gm/cm2; p = 0.02, 573.4 +/- 109.9 gm/cm2 vs. 641.0 +/- 138.0 gm/cm2, p = 0.005 and 1008.6 +/- 185.5 gm/cm2 vs. 938.0 +/- 145.3 gm/cm2 p = 0.0131 respectively). Bone mineral density at lumbar spine expressed as either T and Z score was significantly higher after treatment (10 months of euthyroid state) (-0.6 +/- 1.3 vs. -1.7 +/- 1.2, p = 0.013 and -0.4 +/- 1.2 vs. -1.4 +/- 1.2, p = 0.012 respectively). However Bone mineral measures as T and Z score at left forearm decreased significantly after one year of medical therapy.

CONCLUSION

In Indian patients with hyperthyroidism, the pattern of recovery of bone loss after one year of antithyroid therapy suggests early recovery at hip and lumbar spine and deterioration at forearm.

Thyrotoxicosis presenting as acute bulbar palsy

Myopathy chiefly affecting the proximal muscles of the limbs is frequently seen in hyperthyroidism. But isolated acute bulbar palsy without skeletal muscle involvement is rare in thyrotoxicosis. We report the case of a 52 year old man who presented with severe dysphagia, dysphonia and bouts of aspiration. Laboratory testing revealed an underlying Graves' thyrotoxicosis. His symptoms recovered dramatically within 6 weeks with treatment of hyperthyroidism. This case is reported to emphasize that thyrotoxicosis should be considered in the differential diagnosis of dysphagia of obscure etiology.

A very rare case of bloody tears with enigmatic epistaxis and haematuria

BACKGROUND

Bloody tears are a rare symptom that can be caused by local or systemic pathology.

METHODS

We describe a very rare case of bloody tears that resulted from hyperthyroidism.

RESULTS

A 15-year-old female patient presented with a 6-month history of bloody tears and epistaxis. Examination excluded local ocular and nasal pathology, including neoplasm and coagulopathy. Systemic investigations identified elevated thyroid function and following treatment her symptoms resolved. We discuss the mechanism by which hyperthyroidism may induce haemostatic dysfunction.

CONCLUSION

We present the first case of bloody tears secondary to thyroid dysfunction.

[Elevation of hepatic enzyme values in hyperthyroidism]

Serum or plasma alanine aminotransferase (ALAT) activity may sometimes exhibit even considerable increases in connection with hyperthyroidism and present a diagnostic as well as a therapeutic problem. Open questions include whether the hepatic change is related to a primary disease, and how to select treatment. We report two patients, in whom carbimazole medication initiated for Graves' disease normalized elevated ALAT values.

Treatment of hyperthyroidism in pregnancy and birth defects

CONTEXT

Clinical hyperthyroidism is not uncommon in pregnancy, with a reported prevalence of 0.1 to 0.4%. The available antithyroid drugs are propylthiouracil and methimazole/carbimazole.

OBJECTIVES

In this report we examined the association of both drugs with congenital malformations using data from the International Clearinghouse for Birth Defects Surveillance and Research.

DESIGN

The study used a case-affected control analysis and included 18,131 cases with malformations and reported first-trimester exposure to medication. A total of 127 subjects were born to mothers with known first-trimester antithyroid drug exposure.

RESULTS

Among the 52 groups of malformations that were analyzed, situs inversus ± dextrocardia, isolated unilateral kidney a/dysgenesis, and cardiac outflow tract defects were associated with prenatal exposure to propylthiouracil based on three, two, and five cases, respectively. Prenatal exposure to methimazole/carbimazole was significantly associated with choanal atresia, omphalocele, and total situs inversus ± dextrocardia (P < 0.01).

CONCLUSIONS

Further studies are required to exhaustively evaluate the associations between propylthiouracil and birth defects because of the low number, the lack of biological plausibility, and the possibility of underdiagnosis. Association between methimazole/carbimazole exposure and omphalocele and choanal atresia is consistent with previous reports and definitely suggests that these malformations could be part of a specific, even if rare, embryopathy.

Hyperthyroidism in a case of Down syndrome

An 18 years old mentally retarded male, with morphologic features suggestive of Down syndrome was admitted with fever since 3 weeks. Karyotyping proved trisomy 21. Prominent thyroid swelling with resting tachycardia and hyper-irritability was present. He was found to have multiple renal abscesses and was treated with antibiotics. Thyroid function tests revealed hyperthyroidism which responded to anti-thyroid drugs. So, we report this case of Down syndrome with hyperthyroidism which is a rare association.

Pharmacological treatment of hyperthyroidism during lactation: review of the literature and novel data

Antithyroid drugs (ATD) are used as a first line treatment in thyrotoxicosis. Propylthiouracil (PTU), carbimazole (CMZ) and methimazole (MMI) are available. During absorption CMZ is bioactivated to MMI. Initially, mothers were not allowed to breastfeed during treatment with ATD. Newer studies minimized the risk for mother and infant. PTU should be preferred over MMI due to its lower milk concentration. Recent studies have shown severe hepatic dysfunction for both ATD, but especially for PTU, in hyperthyroid patients. Most of those cases were idiosyncratic, not-dose related and presented a latent period of occurrence. No biomarkers could predict hepatic damage. The American Thyroid Association (ATA) has recommended that PTU should not be prescribed as the first line agent in children and adolescents. Its use might be accepted in the first trimester of pregnancy for severe thyrotoxicosis or for patients with previous MMI adverse reactions. Considering the potential harmful effects of PTU, MMI should be used instead during lactation.

Juvenile thyrotoxicosis--a South Island, New Zealand experience with long-term outcome

AIM

To assess our experience in the management of juvenile thyrotoxicosis.

METHOD

Retrospective review of thyroid clinic records of juvenile (<16 y) thyrotoxic (JT) patients treated at thyroid clinic between 1972 and 1999. Long-term (>8 y) treatment outcome was assessed.

RESULTS

During the 28-year period, 34 JT patients were diagnosed and treated--30 girls and 4 boys, median age 13 years (5.6-15.9 y). Thirty-two children had Graves' disease and two had toxic nodular goitre. All patients were initially treated with carbimazole, and no major adverse reactions occurred. One Graves' disease child later developed severe ophthalmopathy. During long-term follow-up, 12 of the 32 Graves' patients remain in remission after antithyroid drug treatment alone, but 4 of these 12 patients are currently receiving thyroxine replacement. Fifteen patients were surgically treated (median age 16 y), and six patients received radioiodine therapy (median age 18 y) including one patient with post-thyroidectomy relapse. The two patients with toxic nodular goitre were treated by thyroidectomy.

CONCLUSION

Juvenile thyrotoxicosis is relatively rare and not always due to Graves' disease. More than a third of children with Graves' disease achieved long-term remission following antithyroid drug therapy, and remaining patients required definitive therapy.

Serum chromogranin A concentration in hyperthyroidism before and after medical treatment

OBJECTIVE

The aim was to evaluate changes in chromogranin A (CgA) concentration in hyperthyroidism and to assess its metabolic correlations.

METHODS

We studied CgA levels in hyperthyroidism. First, 38 hyperthyroid patients matched with 86 normal controls were studied after an overnight fast. Second, 30 if the 38 patients were followed up for 6 months with medical antithyroid drug therapy (carbimazole). In the first study, after 10-12 h overnight fasting, blood was collected for measurement of CgA, glucose, insulin, intact proinsulin, and thyroid function. These variables were remeasured in the second study for the patients after attainment of euthyroidism with the antithyroid drug carbimazole for 6 months.

RESULTS

Pretreatment CgA level was significantly higher in patients compared with controls. CgA levels dropped significantly to levels similar to those of controls after antithyroid therapy. Although baseline and follow-up fasting glucose, insulin, and intact proinsulin demonstrated similar pattern of CgA changes before and after medical treatment, CgA did not correlate with any of them. However, CgA levels demonstrated a significant positive correlation with free T(3) and free T(4) only.

CONCLUSION

These studies demonstrate that untreated hyperthyroidism is associated with elevated CgA level that changes in parallel to thyroid status. It is therefore possible to use CgA concentration as a potential marker of disease activity in hyperthyroidism.

Hyperthyroidism in a population with Down syndrome (DS)

BACKGROUND

Thyroid disorders are frequent in patients with Down syndrome (DS). It is well-known that the prevalence of hypothyroidism is high but data on hyperthyroidism are scarce.

OBJECTIVES

To assess the prevalence, aetiology, clinical characteristics, evolution and treatment of hyperthyroidism in a population with DS attending a specialized medical centre.

METHODS

Data were gathered by systematic review of 1832 medical records from the Catalan DS Foundation, in Spain, registered between January 1991 and February 2006. Patients with the diagnosis of hyperthyroidism were identified and data on clinical features, physical examination, laboratory and imaging tests, treatment and evolution were collected.

RESULTS

Twelve patients with hyperthyroidism were recorded (6.5 cases/1000 patients with DS). There were 5 males and 7 females, with a mean age at diagnosis of 16.8 years. The most common presenting symptoms were decreased heat tolerance, sweating, increased irritability and weight loss. All patients had diffuse goitre at physical examination and two patients presented with exophthalmia. Clinical diagnosis was confirmed biochemically. Thyroid-stimulating immunoglobulin levels were raised (mean 128.1 U/l) and imaging tests confirmed the diagnosis of Graves' disease in all cases. Patients started treatment with carbimazole at diagnosis and after a mean period of 40 months without clinical remission, they required definitive therapy with radioactive iodine. Subjects developed hypothyroidism after radio-iodine therapy and replacement therapy with levothyroxine was necessary.

CONCLUSIONS

Hyperthyroidism is more prevalent in patients with DS than in the general population and has no gender predominance. It is caused mainly by Graves' disease. Anti-thyroid drugs were not effective in achieving remission and radioactive iodine as a definitive treatment was required in all cases.

Serum lipoprotein and apolipoprotein concentrations in patients with hyperthyroidism and the effect of treatment with carbimazole

Forty patients, 32 women and 8 men, with hyperthyroidism were investigated concerning serum lipoprotein lipid and apolipoprotein concentrations before, during and after treatment with carbimazole to euthyroidism. During the hyperthyroid condition the patients had significantly lower serum concentrations of low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol. The serum lipoprotein triglyceride concentrations were within the normal ranges. During treatment to euthyroidism the low serum concentrations of LDL and HDL cholesterol increased to normal values. LDL and HDL concentrations increased in the female patient group by 46 +/- 12 and 25 +/- 9% and in the male patient group by 50 +/- 12 and 19 +/- 11%, respectively. During treatment serum apolipoprotein B and A-I concentrations increased significantly in females by 58 +/- 9 and 18 +/- 5% and in males by 60 +/- 9 and 13 +/- 8%, respectively.

The effects of long-term antithyroid drug treatment on serum reverse T3 in patients with Graves' disease

The effects of long-term treatment with antithyroid drugs, carbimazole (CMI) or propylthiouracil (PTU), on serum reverse triiodothyronine (rT3) levels were studied in 23 patients with Graves' disease. Nineteen patients were given CMI and four PTU for a minimum of six months. After one month of treatment the serum levels of thyroxine (T4), triiodothyronine (T3) and rT3 had normalized in both groups. When L-thyroxine was added to the regimens after two months of therapy, both serum T4 and rT3 levels increased, whereas serum T3 level continued to fall. The serum levels of rT3 seemed to be dependent on and followed the T4 levels so closely that determinations of rT3 in the medical management of patients with Graves' disease will be of little clinical use.

The course of endocrine ophthalmopathy during antithyroid therapy in a prospective study

In a prospective study the ocular manifestations of 105 thyrotoxic patients were carefully observed and registered during a 24-month antithyroid drug therapy. The treatment was supervised very closely and every effort was made to avoid iatrogenic hypothyroidism. None of the patients required any ocular surgery and in none did the ophthalmopathy become significantly worse. This favourable experience may indicate that a careful antithyroid regimen as outlined is not likely to be accompanied by worsening of the endocrine ophthalmopathy.

Graves disease associated with chronic idiopathic urticaria: 2 case reports

Chronic idiopathic urticaria (CIU) is well known to be associated with antithyroid peroxidase antibodies and autoimmune thyroiditis. Coexisting Graves disease has only rarely been observed. We describe 2 patients with CIU who developed autoimmune hyperthyroidism with antithyrotropin receptor antibodies. Antithyroid peroxidase antibodies were also present in 1 of the patients, but both responded poorly to high-dose antihistamine therapy. Both patients improved significantly, and their thyroid function recovered with carbimazole. We advise clinicians to be alert to the symptoms of hyperthyroidism when patients with CIU respond poorly to antihistamine therapy, as prompt treatment of hyperthyroidism significantly improves urticaria.

Atypical thyrotropin-secreting pituitary microadenoma revealed by severe osteoporosis in a young man

For 10 years, a young man was followed for a severe osteoporosis associated with a considerable reduction in height and a massive weight loss. The constant increase of signs of tissue impregnation with thyroid hormones and the molar ratios of alpha-TSH suggested an inappropriate secretion of thyrotropin. Magnetic resonance imaging finally revealed a thyrotropic microadenoma of the pituitary gland. This case gives some new additional information on thyrotropin-induced osteoporosis. To our knowledge such a case has never been reported in the literature.