Heterogeneity of amiodarone-induced thyrotoxicosis: evaluation of colour-flow Doppler sonography in predicting therapeutic response

To PLEX or Not to PLEX for Amiodarone-Induced Thyrotoxicosis

Amiodarone-induced thyrotoxicosis (AIT) carries significant cardiovascular morbidity. There are two types of AIT with treatment including antithyroid medications and corticosteroids and treatment of ventricular arrhythmias. Therapeutic plasma exchange (TPE) also known as "PLEX" may help remove thyroid hormones and amiodarone. We report a case of PLEX in an attempt to treat cardiogenic shock secondary to AIT. This case highlights the robust rapidly deleterious demise of AIT, specifically in patients with decompensated heart failure. The decision to PLEX or not to PLEX for AIT should be individualized, prior to definitive therapy.

The management and metabolic characterization: hyperthyroidism and hypothyroidism

Hyperthyroidism and hypothyroidism are common diseases resulting from thyroid dysfunction, and are simple to diagnose and treat. The traditional treatment for hypothyroidism is thyroid hormone replacement therapy. The traditional treatments for hyperthyroidism include antithyroid drug, iodine radiotherapy, and surgery. Thyroid disease can be fatal in severe cases if untreated. Current statistical reference ranges used for diagnosis based on relevant biochemical parameters have been debated, and insufficient treatment can result in long-term thyroid hormone deficiency, which is associated with increased risk of cardiovascular disease and persistent symptoms. In contrast, overtreatment can result in heart disease and osteoporosis, particularly in older people and pregnant women. Therefore, under- or over-treatment should be avoided and treatment regimens should be monitored closely. A significant proportion of patients who achieve biochemical treatment goals still complain of significant symptoms. Systematic literature review was performed through the Embase (Elsevier), PubMed and Web of Science databases, and studies summarized evidence regarding treatment and management of hypothyroidism and hyperthyroidism, and reviewed clinical practice guidelines. We also reviewed the latest research on the metabolic mechanisms of hyperthyroidism and hypothyroidism, which contributed to understanding of thyroid diseases in the clinic. A reliable algorithm is needed to management, assessment, and treatment patients with hyperthyroidism and hypothyroidism, which can not only improve management efficiency, but also providing a broad application. In addition, the thyroid disorder showed a lipid metabolism tissue specificity in the Ventromedial Hypothalamus, and effect oxidative stress and energy metabolism of whole body. This review summarizes an algorithm for thyroid disease and the latest pathogenesis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

[Clinical practice guidelines for acute and chronic thyroiditis (excluding autoimmune thyroiditis)]

Острые и хронические заболевания щитовидной железы занимают второе место по выявляемости после сахарного диабета. Всемирная организация здравоохранения отмечает ежегодную тенденцию к увеличению числа заболеваний щитовидной железы. В настоящих клинических рекомендациях будут рассмотрены вопросы этиологии, клинического течения, диагностики и лечения острых и хронических (за исключением аутоиммунного) воспалительных заболеваний щитовидной железы.Клинические рекомендации — это основной рабочий инструмент практикующего врача, как специалиста, так и врача узкой практики. Лаконичность, структурированность сведений об определенной нозологии, методов ее диагностики и лечения, базирующихся на принципах доказательной медицины, позволяют в короткий срок дать тот или иной ответ на интересующий вопрос специалисту, добиваться максимальной эффективности и персонализации лечения.Клинические рекомендации составлены профессиональным сообществом узких специалистов, одобрены экспертным советом Министерства здравоохранения РФ. Представленные рекомендации содержат максимально полную информацию, которая требуется на этапе диагностики острых и хронических тиреоидитов, этапе выбора тактики ведения пациентов с тиреоидитом, а также на этапе лечения пациента.Рабочая группа представляет этот проект в профессиональном журнале, посвященном актуальным проблемам эндокринологии, с целью повышения качества оказываемой медицинской помощи, повышения эффективности лечения острых и хронических тиреоидитов путем ознакомления с полным тестом клинических рекомендаций по острым и хроническим тиреоидитам (исключая аутоиммунный тиреоидит) максимально возможного количества специалистов в области не только эндокринологии, но и медицины общей (семейной) практики.

Amiodarone Induced Thyrotoxicosis and Treatment Complications in a Man With Cyanotic Congenital Heart Disease: A Case Report

Background and Case: Amiodarone induced thyrotoxicosis (AIT) is a potentially life-threatening condition that exists in two main subtypes – AIT Type 1 (AIT1) and AIT Type 2 (AIT2). AIT1 is a form of iodine-induced hyperthyroidism with increased thyroid hormone synthesis, while AIT2 is a form of destructive thyroiditis with increased release of pre-formed thyroid hormone. This case report describes a patient with cyanotic congenital heart disease, who developed AIT with severe biochemical thyrotoxicosis. Due to complications to corticosteroids and thionamides, second-line treatment with cholestyramine and lithium was given which eventually restored euthyroidism, averting the need for thyroidectomy and its associated risks. Due to the presence of both typical and unusual features, the final diagnosis of AIT2 could only be retrospectively elucidated after a prolonged clinical course.

Conclusion: Corticosteroids are well-recognized to be the first-line treatment for AIT2. This case illustrates a rare phenomenon: successful treatment of AIT2 with lithium and cholestyramine. In patients who develop complications from first-line therapy, prompt treatment with alternative agents may successfully avert thyroidectomy and its associated risks.

Amiodarone-Induced Thyrotoxicosis: Differential Diagnosis Using 99mTc-SestaMIBI and Target-to-Background Ratio (TBR)

PURPOSE OF THE REPORT

Distinguishing between amiodarone-induced thyrotoxicosis (AIT) caused by excessive hormone synthesis (AIT-1) or by a destructive process (AIT-2) has important therapeutic implications, but is still difficult and debated. Tc-sestaMIBI thyroid scintigraphy (99m-STS) has been proposed as a tool for classifying the two forms.

MATERIAL AND METHODS

30 AIT patients (11 females and 19 males) who underwent 99m-STS were retrospectively assessed for the present study. For each patient, a target-to-background ratio (TBR) was obtained on planar images. The TBR was then correlated with the qualitative assessment of the scans and the final clinical diagnosis.

RESULTS

Considering clinical response to treatment as the gold standard for differential diagnosis, 14 cases of AIT-1, 12 of AIT-2, and 4 mixed forms were identified. 99m-STS was able to qualitatively identify all the mixed forms, while 1/14 AIT-1 and 6/12 AIT-2 cases were misdiagnosed as mixed forms. When the quantitative index (the TBR) was compared with the final clinical diagnosis, ROC curve analysis enabled us to identify an IBR of 0.482 during 99m-STS as a cut-off capable of discriminating between AIT-1 and AIT-2, with 100% specificity and 91.7% sensitivity (P < 0.0001, area under the curve: 0.982).

CONCLUSIONS

Taking the TBR into consideration, 99m-STS proved a very useful tool for distinguishing AIT-1 from AIT-2, and thus offering patients appropriate treatment as of their diagnosis. This approach can avoid pointless and potentially dangerous combined overtreatments, and may speed up the return to normal thyroid function, which is crucial in AIT patients suffering from heart disease.

[Challenges in the management of amiodarone-induced thyrotoxicosis]

Amiodarone, a benzofuranic iodine-rich pan antiarrhythmic drug, is frequently associated with thyroid dysfunction. This side effect is heterogeneous and unpredicted, motivating regular evaluation of thyroid function tests. In contrary to hypothyroidism, amiodarone-induced thyrotoxicosis (AIT) is a challenging situation owing to the risk of deterioration of the general and cardiac status of such debilitating patients. Classically, AIT is either an iodine-induced thyrotoxicosis in patients with an abnormal thyroid (type I), or due to a subacute thyroiditis on a "healthy" thyroid (type II). Even if many studies tried to better identify the types of AIT, the diagnostic dilemma of type of AIT could be present, and many patients are treated by an association of antithyroid drugs (useful for type I AIT) with corticoids (useful for type II AIT). Being the main etiological factor in AIT, amiodarone is supposed to be stopped, but it could remain the only anti-arrhythmic option that is needed to be either continued or reintroduced to improve the cardiovascular survival. Recently, many studies demonstrated that amiodarone could be continued or reintroduced in patients with history of type II AIT. Nevertheless, in the other patients, amiodarone maintenance complicates the therapeutic response to the antithyroid drugs and increases the risk of AIT recurrence. Thus, amiodarone therapy is preferred to be interrupted. In such patients, thyroid ablation is recommended once AIT is under control.

Issues in amiodarone-induced thyrotoxicosis: Update and review of the literature

Amiodarone, a benzofuranic iodine-rich pan-anti-arrhythmic drug, induces amiodarone-induced thyrotoxicosis (AIT) in 7-15% of patients. AIT is a major issue due to its typical severity and resistance to anti-thyroid measures, and to its negative impact on cardiac status. Classically, AIT is either an iodine-induced thyrotoxicosis in patients with abnormal thyroid (type 1), or due to acute thyroiditis in a "healthy" thyroid (type 2). Determination of the type of AIT is a diagnostic dilemma, as characteristics of both types may be present in some patients. As it is the main etiological factor in AIT, it is recommended that amiodarone treatment should be stopped; however, it may be the only anti-arrhythmic option, needing to be either continued or re-introduced to improve cardiovascular survival. Recently, a few studies demonstrated that amiodarone could be continued or re-introduced in patients with history of type-2 AIT. However, in the other patients, it is recommended that amiodarone treatment be interrupted, to improve response to thioamides and to alleviate the risk of AIT recurrence. In such patients, thyroidectomy is recommended once AIT is under control, allowing safe re-introduction of amiodarone.

Management of Amiodarone-Induced Thyrotoxicosis at a Cardiac Transplantation Centre

Background: Amiodarone-induced thyrotoxicosis (AIT) is associated with significant morbidity and mortality, particularly in patients with cardiac failure. The aim of the study was to evaluate the management of AIT at a tertiary hospital specialising in cardiac failure and transplantation. Methods: Retrospective audit of 66 patients treated for AIT by Endocrinology (2007-2016), classified as type 1 (T1) or type 2 (T2) based on radiological criteria. Main outcome measurements were response rate to initial treatment, time to euthyroidism, and frequency/safety of thyroidectomy. Results: Mean age was 60 ± 2 years; 80% were male. Sixty-four patients commenced medical treatment: thionamides (THIO) in 23, glucocorticoids (GC) in 17 and combination (COMB) in 24. Median thyroxine (fT4) was 35.1 (31.2-46.7) in THIO, 43.1 (30.4 -60.7) in GC, and 60.0 (39.0 ->99.9) pmol/L in COMB (p = 0.01). Initial therapy induced euthyroidism in 52%: 70% THIO, 53% GC, and 33% COMB (p = 0.045) by 100 (49-167), 47 (35-61), and 53 (45-99) days, respectively (p = 0.02). A further 11% became euthyroid after transitioning from monotherapy to COMB. Thyroidectomy was undertaken in 33%. Patients who underwent thyroidectomy were younger (54 ± 3 vs. 63 ± 2 years; p = 0.03), with higher prevalence of severely impaired left ventricular function prior to diagnosis of AIT (38 vs. 18%; p = 0.08). Despite median American Society of Anaesthesiologists classification 4, no thyroidectomy patient experienced cardiorespiratory complications/death. Conclusions: Patients with AIT had limited response to medical treatment. The poorest response was observed in COMB group, likely related to greater hyperthyroidism severity. Thyroidectomy is safe in patients with severe cardiac failure if performed in a centre with cardiac anaesthetic expertise. There should be low threshold for proceeding to thyroidectomy in patients with severe AIT and/or cardiac failure.

2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis

BACKGROUND

Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This document describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

METHODS

The American Thyroid Association (ATA) previously cosponsored guidelines for the management of thyrotoxicosis that were published in 2011. Considerable new literature has been published since then, and the ATA felt updated evidence-based guidelines were needed. The association assembled a task force of expert clinicians who authored this report. They examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to update the 2011 text and recommendations. The strength of the recommendations and the quality of evidence supporting them were rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group.

RESULTS

Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' orbitopathy; and management of other miscellaneous causes of thyrotoxicosis. New paradigms since publication of the 2011 guidelines are presented for the evaluation of the etiology of thyrotoxicosis, the management of Graves' hyperthyroidism with antithyroid drugs, the management of pregnant hyperthyroid patients, and the preparation of patients for thyroid surgery. The sections on less common causes of thyrotoxicosis have been expanded.

CONCLUSIONS

One hundred twenty-four evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Thyrotoxicosis associated with the use of amiodarone: the utility of ultrasound in patient management

Amiodarone is an anti-arrhythmic drug that commonly affects the thyroid, causing hypothyroidism or thyrotoxicosis. Amiodarone-induced thyrotoxicosis (AIT) is caused by excessive thyroid hormone biosynthesis in response to iodine load in autonomously functioning thyroid glands with pre-existing nodular goitre or underlying Graves' disease (type 1 or AIT 1), or by a destructive thyroiditis typically occurring in normal glands (type 2 or AIT 2). Indeterminate or mixed forms are also recognized. The distinction is clinically useful as AIT 1 is treated predominantly with thionamides, whereas AIT 2 is managed with glucocorticoids. We review the tools used to differentiate type 1 from type 2 thyrotoxicosis, with specific reference to the imaging modalities used.

An audit of amiodarone-induced thyrotoxicosis--do anti-thyroid drugs alone provide adequate treatment?

INTRODUCTION

Amiodarone is a widely used anti-arrhythmic drug. A common long-term complication is amiodarone-induced thyrotoxicosis (AIT). We examined retrospectively the efficacy of anti-thyroid drugs with or without prednisolone and the role of surgical thyroidectomy in the treatment of AIT in a single centre, in an iodine-replete region of Australia.

METHODS

A retrospective audit of patients with AIT was performed between 2002-2012 at this centre. Twenty-seven patients, mean age 60.9 ± 2.3 years were identified. Medical therapy (anti-thyroid drugs, prednisolone) was commenced according to the treating endocrinologist. The main outcomes were time to euthyroidism and number proceeding to thyroidectomy.

RESULTS

Of 11 patients commenced on anti-thyroid drugs alone, seven (64%) required the addition of prednisolone. Baseline free T4 was significantly higher in those ultimately treated with prednisolone (58.4 ± 6.3pmol/L) versus those not (31.7 ± 3.4pmol/L, P<0.05). Although similar results were seen with free T3, the difference was not significant (P=0.06). In patients with baseline free T4 <30pmol/L, 75% (3/4) achieved euthyroidism without prednisolone. Neither the use of prednisolone nor continuation of amiodarone significantly influenced time to euthyroidism. Eleven patients (41%) proceeded to surgical thyroidectomy, which was undertaken by an experienced surgical team without significant complications and no mortality.

CONCLUSION

Patients with AIT generally required glucocorticoids. Mild disease (free T4 <30pmol/L) may be successfully treated with anti-thyroid drugs alone. Surgical thyroidectomy is a safe and effective treatment for those refractive to medical therapy.

A semi-quantitative approach to compare high-sensitivity power Doppler sonography and conventional power Doppler sonography in the assessment of thyroid vascularity

BACKGROUND

Ultrasound is a useful imaging tool in the assessment of thyroid glands, and Doppler ultrasound helps in the evaluation of thyroid vascularity. This study was undertaken to evaluate the difference in the thyroid vascularity demonstrated on the state-of-the-art high-sensitivity power Doppler sonography (HSPDS) and the conventional power Doppler sonography (PDS), and to investigate the feasibility of using a customized algorithm with image-processing software for semi-quantitative assessment of thyroid vascularity.

METHODS

A total of 25 healthy volunteers were included in the study, and each subject had two thyroid ultrasound examinations with HSPDS and PDS, respectively. High sensitivity and conventional power Doppler sonograms of the thyroid glands were taken and recorded. To evaluate the vascularity of thyroid lobes quantitatively, a customized algorithm using the software Matlab was developed and used to analyze the ultrasound images. The vascularity of thyroid lobe (i.e., region of interest, ROI) was expressed as the vascular index (VI), which is the ratio of the number of color pixels to the total number of pixels within the ROI.

RESULTS

Results showed that thyroid vascularity was detected in all thyroid lobes on both HSPDS and PDS. The mean VI of the thyroid lobes on HSPDS (right lobe, 0.31 +/- 0.08; left lobe, 0.32 +/- 0.07) was significantly higher than on PDS (right lobe, 0.18 +/- 0.09; left lobe, 0.16 +/- 0.08) (p < 0.05). There was no significant difference in the VI between the right and left thyroid lobes (p >0.05). On HSPDS, 96% of the thyroid lobes showed a VI <0.5, while 96% of thyroid lobes had a VI <0.3 on PDS.

CONCLUSIONS

HSPDS is more sensitive than PDS in the detection of thyroid vascularity. The developed algorithm can quantify the color pixels on power Doppler sonograms, which is useful for objective assessment of thyroid vascularity.

Amiodarone and the thyroid

Among the drugs affecting the thyroid gland, no drug has puzzled, and at the same time fascinated, endocrinologists more than amiodarone. Amiodarone is a potent class III anti-arrhythmic drug that also possesses beta-blocking properties. It is very rich in iodine, with a 100-mg tablet containing an amount of iodine that is 250 times the recommended daily iodine requirement. Amiodarone produces characteristic alterations in thyroid function tests in euthyroid patients. Understanding these alterations is crucial in avoiding unnecessary investigations and treatment. Amiodarone-induced thyroid dysfunction occurs because of both its iodine content and the direct toxic effects of the compound on thyroid parenchyma. Amiodarone-induced hyperthyroidism is more common in iodine-deficient regions of the world, whereas amiodarone-induced hypothyroidism is usually seen in iodine-sufficient areas. In contrast to amiodarone-induced hypothyroidism, amiodarone-induced thyrotoxicosis is a difficult condition to diagnose and treat. In this review, we discuss the alterations in thyroid function tests seen in euthyroid subjects, the epidemiology and mechanism of amiodarone-induced thyroid dysfunction, treatment options available, and the consequences of amiodarone use in pregnancy and lactation; and finally, we propose a follow-up strategy in patients taking amiodarone.

5: Diagnosis and management of hyperthyroidism and hypothyroidism

The most common cause of hyperthyroidism in Australia is Graves disease, caused by a defect in immunoregulation in genetically predisposed individuals, leading to production of thyroid-stimulating antibodies. Each of the three modalities of therapy for Graves disease--thionamide drugs, subtotal or total thyroidectomy, and radioactive iodine ablation--can render the patient euthyroid, but all have potential adverse effects and may not eliminate recurrences. Hypothyroidism occurs in about 5% of the adult population; most present with "subclinical" hypothyroidism (mild thyroid failure), characterised by raised levels of serum thyroid stimulating hormone (TSH) but normal free thyroxine (T(4)). The most common cause of hypothyroidism in Australia is autoimmune chronic lymphocytic thyroiditis, characterised by raised circulating levels of thyroid peroxidase antibody. Symptoms and signs of hypothyroidism are often mild or subtle and, when there is clinical suspicion, thyroid function tests are needed; if serum TSH level is raised, free T(4) and thyroid peroxidase antibody should be measured. Replacement therapy with thyroxine is the cornerstone of therapy (1.6 microg/kg lean body weight daily, taken on an empty stomach); combination therapy with thyroxine and liothyronine (T(3)) is promoted, but there is little evidence of its clinical benefit. Despite the development of highly sensitive laboratory tests, clinical assessment and judgement remain paramount