Rapid preoperative preparation in hyperthyroidism

Preoperative Preparation in Hyperthyroidism and Surgery in the Hyperthyroid State

Hyperthyroidism is a clinical condition that develops due to the excessive production and secretion of thyroid hormones by the thyroid gland, leading to an elevated concentration of thyroid hormones in tissues. Hyperthyroidism is characterized by low TSH and elevated T3 and/or T4, with the most common causes being Graves' disease, toxic multinodular goiter, and solitary toxic adenoma. T3 is the peripherally active form of thyroid hormone, affecting nearly each tissue and system. The most prominent aspects of hyperthyroidism are related to the cardiovascular system. The treatment of hyperthyroidism includes three options: antithyroid drugs (ATDs), radioactive iodine therapy (RAI), and surgery. Among these treatment modalities, surgery is considered as the most effective one. For patients who are candidates for surgery, preoperative preparation is required to ensure that the thyroidectomy can be performed under optimal conditions. Preoperative preparation should be a combination therapy aimed at preventing the synthesis, secretion, and peripheral effects of thyroid hormones from the thyroid gland. Medications that can be used in this treatment include thionamides, beta-blockers, iodine, corticosteroids, cholestyramine, perchlorate, lithium, and therapeutic plasma exchange. These treatment options can be combined based on the patient's condition. While it is recommended that patients be made euthyroid through preoperative antithyroid treatment to prevent the feared complication, which is the thyroid storm, the supporting evidence is limited. Preoperative treatment does not prevent against thyroid storm whether the patient is euthyroid or hyperthyroid during surgery. Whether surgery should be delayed until biochemical euthyroidism is achieved in hyperthyroid patients remains a topic of debate. Recent studies suggest that thyroidectomy can be safely performed during the hyperthyroid phase by experienced anesthesiologists and surgeons without precipitating thyroid storm or increasing intraoperative and postoperative complications. Although achieving the euthyroid state before surgery is ideal in hyperthyroid patients, it is not always possible. Factors such as allergies to medications, drug side effects, treatment-resistant disease, patient noncompliance, and the urgency of definitive treatment are critical in determining whether hyperthyroidism can be controlled preoperatively. When surgery is necessary in hyperthyroid patients without achieving euthyroidism, the patient's overall condition and comorbidities should be evaluated together by the anesthesiologist, surgeon and endocrinologist, with particular attention to stabilizing the cardiovascular system. We believe that in hyperthyroid patients who are cardiovascularly stable during the hyperthyroid phase, thyroid surgery may not need to be delayed and can be performed safely.

Non-thionamide antithyroid drug options in Graves' hyperthyroidism

INTRODUCTION

The thionamide anti-thyroid drugs namely carbimazole, methimazole, and propylthiouracil, have been the predominant therapy modality for Graves' hyperthyroidism for over 60 years. Although these agents have proven efficacy and favorable side-effect profiles, non-thionamide alternatives are occasionally indicated in patients who are intolerant or unresponsive to thionamides alone. This review examines the available non-thionamide drug options for the control of Graves' hyperthyroidism and summarizes their clinical utility, efficacy, and limitations.

AREAS COVERED

We reviewed existing literature on mechanisms, therapeutic utility, and side-effect profiles of non-thionamide anti-thyroid drugs. Established non-thionamide agents act on various phases of the synthesis, release, and metabolism of thyroid hormones and comprise historical agents such as iodine compounds and potassium perchlorate as well as drug repurposing candidates like lithium, glucocorticoids, beta-blockers, and cholestyramine. Novel experimental agents in development target key players in Graves' disease pathogenesis including B-cell depletors (Rituximab), CD40 blockers (Iscalimab), TSH-receptor antagonists, blocking antibodies, and immune-modifying peptides.

EXPERT OPINION

Non-thionamide anti-thyroid drugs are useful alternatives in Graves' hyperthyroidism and more clinical trials are needed to establish their safety and long-term efficacy in hyperthyroidism control. Ultimately, the promise for a cure will lie in novel approaches that target the well-established immunopathogenesis of Graves' disease.

Perioperative Management for Non-Thyroidal Surgery in Thyroid Dysfunction

Thyroid hormone exerts effects across all organ systems. Hence, patients with thyroid dysfunction are at a risk of numerous complications. The stresses encountered during the perioperative period may exacerbate underlying thyroid disorders, potentially precipitating decompensation, and even death. Thus, it is of the utmost importance for the clinician to comprehend the mechanisms by which thyroid disease may complicate surgery and postoperative recovery and to optimize the status of thyrotoxic and hypothyroid patients. This article describes the adverse effects of thyroid dysfunction in patients undergoing nonthyroid surgery and recommends treatment approaches aimed at appropriate build-up to decrease perioperative risk.

2022 Update on Clinical Management of Graves Disease and Thyroid Eye Disease

The management of hyperthyroidism and extrathyroidal manifestations of Graves disease remains complex. Considerations that include patient preference, age, comorbidity, pregnancy, tobacco smoking, and social determinants of health must all be weaved into a cohesive management plan. A multidisciplinary team is required to manage all aspects of Graves disease, particularly thyroid eye disease, for which new therapeutic options are now available.

Outcomes After Urgent Thyroidectomy Following Rapid Control of Thyrotoxicosis in Graves' Disease are Similar to Those After Elective Surgery in Well-Controlled Disease

BACKGROUND

Surgery for Graves' disease (GD) is usually performed after adequate control with medical treatment. Occasionally, rapid pre-operative optimization is required. The primary objective was to compare the outcomes of patients undergoing elective surgery for well-controlled GD with those undergoing rapid pre-operative treatment. We also propose a formal treatment protocol for future use.

METHODS

A retrospective cohort study in a tertiary referral centre included 247 patients with well-controlled GD undergoing elective surgery and 19 patients with poorly controlled disease undergoing surgery after rapid optimization. The latter group did not respond well to thionamides (carbimazole and/or propylthiouracil) or had intolerance or side effects to thionamides and were treated with a range of non-thionamide drugs, including Lugol's iodine, cholestyramine, beta blockers and steroids (with or without thionamides), and closely monitored for 1-2 weeks before surgery. Outcome measures included thyroid storm, hypoparathyroidism and recurrent laryngeal nerve palsy.

RESULTS

In total, 266 patients with male-to-female ratio of 1:6 and median (interquartile range) age of 39 (31-51) were included. Overall, long-term recurrent laryngeal palsy and hypoparathyroidism occurred in 1 (0.38%) and 13 (4.9%) patients, respectively. No patient had thyroid storm. There was no significant difference in hypoparathyroidism (p = 1), vocal cord palsy (p = 0.803) and post-operative bleeding (p = 0.362), between elective surgery and rapid optimization groups.

CONCLUSION

Rapid pre-operative treatment is effective, safe and is associated with similar outcomes compared to usual treatment. A rapid pre-operative optimization protocol is proposed.

Considerations for Thyroidectomy as Treatment for Graves Disease

Hyperthyroidism is a clinical state that results from abnormally elevated thyroid hormones. Thyroid gland affects many organ systems; therefore, patients usually present with multiple clinical manifestations that involve many organ systems such as the nervous, cardiovascular, muscular, and endocrine system as well as skin manifestations. Hyperthyroidism is most commonly caused by Graves disease, which is caused by autoantibodies to the thyrotropin receptor (TRAb). Other causes of hyperthyroidism include toxic multinodular goiter, toxic single adenoma, and thyroiditis. Diagnosis of hyperthyroidism can be established by measurement of thyroid-stimulating hormone (TSH), which will be suppressed with either elevated free T4 and/or T3 (overt hyperthyroidism) or normal free T3 and T4 (subclinical hyperthyroidism). Hyperthyroidism can be treated with antithyroid drugs (ATDs), radioactive iodine (RAI), or thyroidectomy. ATDs have a higher replacement rate when compared with RAI or thyroidectomy. Recent evidence has shown that thyroidectomy is a very effective, safe treatment modality for hyperthyroidism and can be performed as an outpatient procedure. This review article provides some of the most recent evidence on diagnosing and treating patients with hyperthyroidism.

Review of oral cholecystographic agents for the management of hyperthyroidism

OBJECTIVE

Although the use of oral cholecystographic agents (OCAs) had declined due to limited availability, there is literature to suggest it is an effective medication for thyrotoxicosis in appropriate clinical situations.

METHODS

The authors performed a PubMed search and systematically reviewed all the English written case reports, original studies and reviews from 1953 to 2012. Additional information was supplemented from available online pharmacologic databases.

RESULTS

The off-label use of OCAs was reviewed for the management of neonatal and adult Graves' disease, subacute thyroiditis, amiodarone-induced thyroiditis (AIT), exogenous hyperthyroidism, toxic multinodular goiter (TMNG), thyrotropinoma, thyrotoxicosis during pregnancy, rapid pre-operative control of hyperthyroidism, and thyroid storm. Adverse effects were also reviewed.

CONCLUSION

OCAs generally are effective agents in treating thyrotoxicosis in the etiologies reviewed. OCAs are clinically relevant in patients who require rapid control, such as in the pre-operative state or patient who cannot tolerate a thyrotoxicosis state. OCA may also be beneficial in situations where other anti-thyroidal medication would be hazardous or ineffective, such as thionamide allergy or exogenous thyrotoxicosis. Given concern for long-term relapse, OCAs should be considered a short-term bridge to definitive therapy. OCAs are limited in TMNG and should be second line after glucocorticoids in AIT II. OCAs do not preclude the use of radioactive iodine, which can be performed one week after OCA therapy.

Effects of Preoperative Iodine Administration on Thyroidectomy for Hyperthyroidism: A Systematic Review and Meta-analysis

OBJECTIVE

The current guidelines recommend that potassium iodide be given in the immediate preoperative period for patients with Graves' disease who are undergoing thyroidectomy. Nonetheless, the evidence behind this recommendation is tenuous. The purpose of this study is to clarify the benefits of preoperative iodine administration from published comparative studies.

DATA SOURCES

We searched PubMed, Embase, Cochrane, and CINAHL from 1980 to June 2018.

REVIEW METHODS

Studies were included that compared preoperative iodine administration and no premedication before thyroidectomy. For the meta-analysis, studies were pooled with the random-effects model.

RESULTS

A total of 510 patients were divided into the iodine (n = 223) and control (n = 287) groups from 9 selected studies. Preoperative iodine administration was significantly associated with decreased thyroid vascularity and intraoperative blood loss. Significant heterogeneity was present among studies. We found no significant difference in thyroid volume or operative time. Furthermore, the meta-analysis showed no difference in the risk of postoperative complications, including vocal cord palsy, hypoparathyroidism/hypocalcemia, and hemorrhage or hematoma after thyroidectomy.

CONCLUSION

Preoperative iodine administration decreases thyroid vascularity and intraoperative blood loss. Nonetheless, it does not translate to more clinically meaningful differences in terms of operative time and postoperative complications.

Methamphetamine Use With Subsequent Thyrotoxicosis/Thyroid Storm, Agranulocytosis, and Modified Total Thyroidectomy: A Case Report

Thyroid storm is a rare, potentially lethal condition involving collapse of the hypothalamic-pituitary-thyroid feedback loop. Thyroid storm carries a significant mortality rate, thus requiring prompt identification and treatment. A 47-year-old woman presented to the emergency department complaining of palpitations, shortness of breath, and emesis for 24 hours after using methamphetamine. Past medical history was significant for untreated hyperthyroidism. Physical examination revealed a prominent, palpable thyroid. The Burch-Wartofsky-Score was 35. Management for thyroid storm included propylthiouracil (PTU), super saturated potassium iodide, intravenous hydrocortisone, and propranolol. However, a rare drug reaction to PTU on day 3 resulted in agranulocytosis. Propylthiouracil was withheld and a modified total thyroidectomy performed on day 8 without complications and the patient discharged on day 10 with levothyroxine. Undertreated hyperthyroidism may predispose patients to catecholamine-induced thyrotoxicosis due to catecholamine hypersensitivity. With known methamphetamine use, methamphetamine toxicity and a methamphetamine-exacerbated thyroid storm need to be included in the differential diagnosis in a patient presenting with signs of thyrotoxicosis. In addition, treating patients with agranulocytosis from PTU with a modified total thyroidectomy using ligation of the vascular supply as the initial surgical step limits release of thyroid hormone into the blood stream during thyroidectomy and decreases the possibility of intra operative thyroid storm.

Thyroidectomy for the treatment of Graves' thyrotoxicosis in thioamide-induced agranulocytosis and sepsis

A 51 year old man presented with sepsis in the setting of thioamide-induced agranulocytosis. Empiric broad-spectrum antibiotics was followed by directed narrow-spectrum antibiotics, and his neutrophil count recovered with support from granulocyte-colony stimulating factor (G-CSF) analogue transfusions. After a brief period of multi-modal therapy for nine days including potassium iodide (Lugol's iodine), cholestyramine, propanolol and lithium to temper his persisting hyperthyroidism, a total thyroidectomy was performed while thyroid hormone levels remained at thyrotoxic levels. Postoperative recovery was uncomplicated and he was discharged home on thyroxine. There is limited available evidence to guide treatment in this unique cohort of patients who require prompt management to avert impending clinical deterioration. This case report summarises the successful emergent control of thyrotoxicosis in the setting of thioamide-induced agranulocytosis complicated by sepsis, and demonstrates the safe use of multi-modal pharmacological therapies in preparation for total thyroidectomy.

LEARNING POINTS

Thioamide-induced agranulocytosis is an uncommon but potentially life-threatening complication of which all prescribers and patients need to be aware.A multi-modal preoperative pharmacological approach can be successful, even when thioamides are contraindicated, when needing to prepare a thyrotoxic patient for semi-urgent total thyroidectomy.There is not enough evidence to confidently predict the safe timing when considering total thyroidectomy in this patient cohort, and therefore it should be undertaken when attempts have first been made to safely reduce thyroid hormone levels.Thyroid storm is frequently cited as a potentially severe complication of thyroid surgery undertaken in thyrotoxic patients, although the evidence does not demonstrate this as a common occurrence.

Rescue pre-operative treatment with Lugol's solution in uncontrolled Graves' disease

BACKGROUND

Graves' disease is a common cause of hyperthyroidism. Three therapies have been used for decades: pharmacologic therapy, surgery and radioiodine. In case of adverse events, especially agranulocytosis or hepatotoxicity, pre-treatment with Lugol's solution containing iodine/potassium iodide to induce euthyroidism before surgery could be advocated, but this has rarely been reported.

METHODS

All patients hospitalised due to uncontrolled hyperthyroidism at the Karolinska University Hospital 2005-2015 and treated with Lugol's solution were included. All electronic files were carefully reviewed manually, with focus on the cause of treatment and admission, demographic data, and effects of iodine on thyroid hormone levels and pulse frequency.

RESULTS

Twenty-seven patients were included. Lugol's solution had been chosen due to agranulocytosis in 9 (33%), hepatotoxicity in 2 (7%), other side effects in 11 (41%) and poor adherence to medication in 5 (19%). Levels of free T4, free T3 and heart rate decreased significantly after 5-9 days of iodine therapy (free T4 53-20 pmol/L, P = 0.0002; free T3 20-6.5 pmol/L, P = 0.04; heart rate 87-76 beats/min P = 0.0007), whereas TSH remained unchanged. Side effects were noted in 4 (15%) (rash n = 2, rash and vomiting n = 1, swelling of fingers n = 1). Thyroidectomy was performed in 26 patients (96%) and one was treated with radioiodine; all treatments were without serious complications.

CONCLUSION

Treatment of uncontrolled hyperthyroidism with Lugol's solution before definitive treatment is safe and it decreases thyroid hormone levels and heart rate. Side effects were limited. Lugol's solution could be recommended pre-operatively in Graves' disease with failed medical treatment, especially if side effects to anti-thyroid drugs have occurred.

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.

Current trends in antithyroid drug treatment of Graves' disease

INTRODUCTION

Graves' hyperthyroidism is associated with significant morbidity and mortality risk. The thionamides, methimazole, its pro-drug derivative carbimazole, and propylthiouracil, remain a cornerstone of management. Yet despite decades of use, optimal strategies for maximising treatment response and curtailing adverse effect risk remains uncertain.

AREAS COVERED

We reviewed the current literature on the evidence based medical management of Graves' disease. Specifically, we evaluated current approaches to the use of thionamides, adjunctive therapies, and potential novel agents for controlling Graves' hyperthyroidism.

EXPERT OPINION

Primary medical therapy is successful in less than 50% of cases and so careful selection of patients for medical treatment based on a combination of pathological and pragmatic considerations is essential. Carbimazole or methimazole is the treatment of choice in the non-pregnant population driven by its more favourable pharmacokinetic and adverse effect profile over propylthiouracil. In pregnancy the choice of treatment is less straightforward and an approach that minimises undue fetal exposure to all thionamides should be adopted. Additional data is needed on the value of adjunctive therapies including potassium perchlorate, iodides, glucocorticoids, lithium, and cholestyramine. Novel agents directed against pathogenetic targets including TSH receptor blocking monoclonal antibodies and small molecule antagonists may hold promise for the future.

The Brazilian consensus for the diagnosis and treatment of hyperthyroidism: recommendations by the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism

INTRODUCTION

Hyperthyroidism is characterized by increased synthesis and release of thyroid hormones by the thyroid gland. Thyrotoxicosis refers to the clinical syndrome resulting from excessive circulating thyroid hormones, secondary to hyperthyroidism or due to other causes. This article describes evidence-based guidelines for the clinical management of thyrotoxicosis.

OBJECTIVE

This consensus, developed by Brazilian experts and sponsored by the Department of Thyroid Brazilian Society of Endocrinology and Metabolism, aims to address the management, diagnosis and treatment of patients with thyrotoxicosis, according to the most recent evidence from the literature and appropriate for the clinical reality of Brazil.

MATERIALS AND METHODS

After structuring clinical questions, search for evidence was made available in the literature, initially in the database MedLine, PubMed and Embase databases and subsequently in SciELO - Lilacs. The strength of evidence was evaluated by Oxford classification system was established from the study design used, considering the best available evidence for each question.

RESULTS

We have defined 13 questions about the initial clinical approach for the diagnosis and treatment that resulted in 53 recommendations, including the etiology, treatment with antithyroid drugs, radioactive iodine and surgery. We also addressed hyperthyroidism in children, teenagers or pregnant patients, and management of hyperthyroidism in patients with Graves' ophthalmopathy and various other causes of thyrotoxicosis.

CONCLUSIONS

The clinical diagnosis of hyperthyroidism usually offers no difficulty and should be made with measurements of serum TSH and thyroid hormones. The treatment can be performed with antithyroid drugs, surgery or administration of radioactive iodine according to the etiology of thyrotoxicosis, local availability of methods and preferences of the attending physician and patient.

Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists

OBJECTIVE

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 article describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspeciality physicians and others providing care for patients with this condition.

METHODS

The development of these guidelines was commissioned by the American Thyroid Association in association with the American Association of Clinical Endocrinologists. The American Thyroid Association and American Association of Clinical Endocrinologists assembled a task force of expert clinicians who authored this report. The task force 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 develop the text and a series of specific recommendations. The strength of the recommendations and the quality of evidence supporting each was 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' ophthalmopathy; and management of other miscellaneous causes of thyrotoxicosis.

CONCLUSIONS

One hundred 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.

Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists

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 article describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspeciality physicians and others providing care for patients with this condition.

METHODS

The development of these guidelines was commissioned by the American Thyroid Association in association with the American Association of Clinical Endocrinologists. The American Thyroid Association and American Association of Clinical Endocrinologists assembled a task force of expert clinicians who authored this report. The task force 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 develop the text and a series of specific recommendations. The strength of the recommendations and the quality of evidence supporting each was 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' ophthalmopathy; and management of other miscellaneous causes of thyrotoxicosis.

CONCLUSIONS

One hundred 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.

Medical management of thyroid eye disease

Thyroid eye disease (TED) is the most common cause of orbital disease in adults. The immunologic pathogenesis of TED has been an area of active research and considerable progress has resulted in an expansion of therapeutic options. Although surgical intervention may be required, a majority of TED patients can be managed with medical therapies. Of medical therapies, glucocorticoids remain the agent of choice in the control of TED activity. The objective of this review is to discuss the paradigm and options in medical management of TED.

Treatment of Graves' hyperthyroidism: evidence-based and emerging modalities

Currently there are three well-established treatment options for hyperthyroid Graves' disease (GD): antithyroid drug therapy with thionamides (ATD), radioactive iodine treatment with (131)I, and thyroid surgery. This article reviews the current evidence so the reader can evaluate advantages and disadvantages of these treatment modalities. Surgery is rarely used, except for patients who have a large goiter or ophthalmopathy. Fewer than 50% of patients treated with ATD remain in long-term remission. Therefore, radioactive iodine is used increasingly. No data as yet support the routine use of biologic therapies (eg, rituximab). Prospective, randomized studies comparing available and any novel therapeutic options for GD are needed. The focus of these studies should include, but not be limited to, cost and quality of life.

Effects and safety of iopanoic acid in cats administered levothyroxine

The purpose of this study was to evaluate the safety and effect of iopanoic acid in 13 cats with hyperthyroidism induced by daily subcutaneous administration of 25microg/kg levothyroxine for a period of 42 days. On day 28 of levothyroxine administration, cats were randomly allocated to receive treatment twice daily with a placebo (control group; n=4), 50mg iopanoic acid (low dose group; n=5), or 100mg iopanoic acid (high dose group; n=4) for 14 days. Compared to the control group, T(3) concentrations were significantly decreased in both the low dose and high dose groups on days 35 and 42. T(3) concentrations in the low dose and high dose groups at days 35 and 42 were not different from day -8. The effect of iopanoic acid on clinical signs of hyperthyroidism was less apparent. Further clinical studies evaluating the long-term effect in cats with spontaneous hyperthyroidism are warranted.

Refractory thyrotoxicosis induced by iodinated contrast agents treated with therapeutic plasma exchange. A case report

Excess free iodide in the blood (ingested or injected) may cause thyrotoxicosis in patients at risk. Iodinated contrast solutions contain small amounts of free iodide and may be of significance for patients affected by Graves' disease, multinodular goiter or living in areas of iodine deficiency. Herein, we report a 57 elderly woman with a clinical history of multinodular goiter presented with a thyrotoxicosis induced by an iodinate contrast agent used during computed tomography scan. Because of the patient's resistance to conventional antithyroid drugs, she was treated with therapeutic plasma exchange (TPE). TPE is used in the treatment of several immunologic and nonimmunologic disorders. Temporary improvement after TPE in cases with thyrotoxicosis has been reported. In our patient's case, we observed an improvement in the thyroid hormone laboratory values as well as clinical findings. TPE can be an addition treatment when standard therapies for thyrotoxicosis fail providing the clinician with an adjuvant tool for rapid preparation of such a patient for thyroidectomy surgery.

Propylthiouracil induced C-ANCA positive agranulocytosis complicating Graves' thyrotoxicosis in pregnancy

BACKGROUND

Thionamide induced agranulocytosis is associated with the presence of anti-neutrophil cytoplasmic antibodies (ANCA) in some patients. This poses a particular challenge when it occurs during pregnancy.

AIMS

To report a case of a 31-year-old woman with Graves' disease who presented at 11 weeks gestation with propylthiouracil induced agranulocytosis.

METHODS

After cessation of propylthiouracil the patient developed recurrent thyrotoxicosis, and underwent an elective subtotal thyroidectomy at 23 weeks gestation.

RESULTS

The patient required postoperative thyroxine replacement therapy. Subsequent pregnancy was uneventful and she delivered a healthy baby boy at 41 weeks gestation. As part of our routine work up for agranulocytosis we measured C-ANCA levels, which were significantly elevated.

CONCLUSION

This case highlights the association of propylthiouracil induced ANCA positivity and agranulocytosis. Second trimester subtotal thyroidectomy was safe and effective in treating this pregnant patient's thyrotoxicosis.

Thyrotoxicosis and thyroid storm

Thyroid storm represents the extreme manifestation of thyrotoxicosis as a true endocrine emergency. Although Grave's disease is the most common underlying disorder in thyroid storm, there is usually a precipitating event or condition that transform the patient into life-threatening thyrotoxicosis. Treatment of thyroid storm involves decreasing new hormone synthesis, inhibiting the release of thyroid hormone, and blocking the peripheral effects of thyroid hormone. This multidrug, therapeutic approach uses thionamides, iodine, beta-adrenergic receptor antagonists, corticosteroids in certain circumstances, and supportive therapy. Certain conditions may warrant the use of alternative therapy with cholestyramine, lithium carbonate, or potassium perchlorate. After the critical illness of thyroid storm subsides, definitive treatment of the underlying thyrotoxicosis can be planned.

Thyroid medications during pregnancy

Euthyroid women experience dramatic changes in their thyroid physiology in order to accommodate the presence of placental and fetal tissues. These adaptations to the pregnant state make it crucial to develop reliable trimester-specific intervals for thyroid parameters. Use of non-pregnant reference intervals could lead to erroneous assessment of thyroid status in this rapidly changing hormonal environment. Only with a full appreciation of physiologic changes in thyroid parameters during a euthyroid pregnancy, can thyroid dysfunction be appropriately diagnosed and managed. Iodine sufficiency during pregnancy can be achieved with supplementation using a multivitamin. Both hypothyroidism and hyperthyroidism should be diagnosed using the appropriate reference intervals for pregnancy. Hypothyroid women are best treated with a specific brand of levothyroxine. Hypothyroidism should ideally be treated prior to conception. If newly recognized during pregnancy, it should be fully treated as early as possible. Frequent monitoring of thyroid status is essential as many women demonstrate an increased requirement for thyroid hormone during the first trimester. Although mild hyperthyroidism may be well tolerated during pregnancy, overt hyperthyroidism requires treatment. Thionamides are the mainstay of therapy. Following their initiation, close monitoring is required to avoid maternal and fetal hypothyroidism. There are occasional circumstances when other medical therapy or surgical therapy may be employed for hyperthyroidism. Thyroidectomy is generally safe in the second trimester in an appropriately prepared woman. There is limited data about the role and safety of oral contrast agents, iodine, amiodarone, and perchlorate. Radioiodine therapy is contradicted during pregnancy.

Hyperthyroidism

The clinical spectrum of hyperthyroidism varies from asymptomatic,subclinical hyperthyroidism to the life-threatening "thyroid storm". Hyperthyroidism is a common form of thyroid disease that mimics many of the common complaints in the emergency department. The diagnosis of hyperthyroidism is often challenging due to the multitude of physical and even psychiatric complaints. Recognition and treatment by emergency physicians of severe hyperthyroidism is critical and can be life saving.

Hyperthyroidism: advantages and disadvantages of medical therapy

The most common causes of hyperthyroidism are Graves' disease, toxic nodular goiter, and iodine-induced hyperthyroidism. Hyperthyroidism can be treated medically with antithyroid drugs or radioactive iodine, or surgically. Multiple clinical factors must be weighed when choosing a treatment modality. All of the available forms of therapy have advantages and disadvantages, and treatment choices must be individualized.

Therapeutic plasmapheresis in patients with severe hyperthyroidism in whom antithyroid drugs are contraindicated

Four patients with Graves' disease in whom antithyroid drugs could not be used were treated by plasmapheresis preoperatively. On admission all patients had severe hyperthyroidism. All patients were treated by beta blockers, cholestyramine and inorganic iodine before plasmapheresis. Plasmapheresis course consisted of three sessions. Removed plasma was replaced by a synthetic colloid solution and human albumin other than fresh-frozen plasma. Plasmapheresis led to decreases in serum T3 concentrations >78-40% and free T4 concentrations >69%. Near-total thyroidectomy could be performed in all patients. Although screening coagulation tests were within normal limits, patients 1 and 4 experienced more blood loss than usual during the operative procedure. Plasmapheresis could be used as an alternative therapeutic option in the preoperative management of severe hyperthyroid patients with contraindications to antithyroid drugs. However, this is an invasive procedure and patients should be followed carefully for prolonged clinic/subclinic coagulopathy due to plasma exchange.

Advantages and disadvantages of surgical therapy and optimal extent of thyroidectomy for the treatment of hyperthyroidism

Surgery is excellent therapy for hyperthyroidism, with no mortality,and few complications or recurrences. It achieves euthyroidism rapidly and consistently, avoids long-term risks of radioactive iodine and antithyroid medications, provides tissue for histology,renders childbearing immediately possible, and allows absolute titration of thyroid hormone. Advancements such as preoperative preparation and intraoperative parathyroid hormone monitoring have decreased risks greatly and improved outcomes. Hartley-Dunhill procedure is the treatment of choice. Patients should be rendered euthyroid before operation to decrease thyroid vascularity, to improve surgical planes, and to prevent life threatening thyroid storm. Patients must be monitored carefully for hypocalcemia, a potentially serious complication. Patients will require lifelong thyroid hormone replacement. Radioactive iodine ablation should be considered for disease recurrence after surgery.

Rapid preparation of severe uncontrolled thyrotoxicosis due to Graves' disease with Iopanoic acid--a case report

PURPOSE

To report the rapid preoperative preparation of a case of thyrotoxicosis due to Graves' disease resistant to medical treatment.

CLINICAL FEATURES

A 14-yr-old boy presented with a history of progressive swelling in the neck. Signs and symptoms were compatible with hyperthyroidism. Thyroid function tests revealed: serum T4 296.5 nmol.L(-1), serum T3 6.06 nmol.L(-1) and serum thyroid-stimulating hormone < 0.15 mIU.L(-1). The diagnosis of thyrotoxicosis due to Graves' disease was made. Therapy was instituted with carbimazole 30 mg.day(-1) and propranolol 80 mg.day(-1), which were gradually increased to carbimazole 80 mg.day(-1) and propranolol 120 mg.day(-1), without response. Preparation was attempted by adding Iopanoic acid 500 mg four times a day and dexamethasone 0.5 mg four times a day in addition to the above drugs for five days. T3 levels declined to 1.8 nmol.L(-1), but the serum T4 remained elevated. Symptoms of hyperthyroidism persisted but with decreased intensity. As the patient could not be made euthyroid, surgery was planned to relieve the symptoms. Anesthesia was uneventful except for intraoperative and postoperative tachycardia, which was managed successfully with esmolol.

CONCLUSION

In life threatening thyrotoxicosis refractory to medical treatment, Iopanoic acid may be used as an adjuvant to antithyroid drugs for rapid preparation of the patient prior to surgery.

Is there a place for thyroidectomy in older patients with thyrotoxic storm and cardiorespiratory failure?

Early thyroidectomy is the treatment of choice for thyrotoxic storm in patients with thyroid autonomy often induced by iodine. However, older patients who are mostly affected by this condition often have underlying chronic cardiopulmonary diseases, apparently contradicting surgical intervention. The published evidence for suitable treatment strategies in these patients is limited. We report the outcome of a series of older critically ill patients who were treated by thyroidectomy because of thyrotoxic storm. We retrospectively analyzed the outcome of 10 patients (4 males, 6 females; 70 years of age, range, 54-79, Burch-Wartofsky point scale, 61; range, 40-85) with thyrotoxic storm, thyroid autonomy, and severe cardiorespiratory and renal failure with cardiac arrhythmia, coronary artery or chronic obstructive pulmonary disease, or acute inflammation. Thyroidectomy was performed for the following reasons: symptoms of thyrotoxic storm deteriorated or did not improve within 24-48 hours despite intensive medical treatment, or patients developed thionamide-induced agranulocytosis or severe thrombocytopenia. All patients with severe accompanying diseases survived thyroidectomy (early post-operative mortality, 0%). The two oldest patients died 2-3 weeks after thyroidectomy because of myocardial infarction or respiratory failure (late postoperative mortality, 20%). In contrast, in the few previous reports of patients who underwent thyroidectomy for thyrotoxic storm and severe accompanying diseases (n = 7), late postoperative mortality was 43%. The overall mortality for all reported patients including our own, who underwent thyroidectomy for thyrotoxic storm with and without severe accompanying disease (n = 49) was 10%. Our results suggest that early total thyroidectomy should be considered as the method of choice for older, chronically ill patients with thyrotoxic storm complicated by cardiorespiratory and renal failure, especially if high-dose thionamide treatment, iopanoic acid, glucocorticoids, and intensive care fail to improve the patient's conditions within 12-24 hours.

Hyperthyroidism

Hyperthyroidism is a pathological syndrome in which tissue is exposed to excessive amounts of circulating thyroid hormone. The most common cause of this syndrome is Graves' disease, followed by toxic multinodular goitre, and solitary hyperfunctioning nodules. Autoimmune postpartum and subacute thyroiditis, tumours that secrete thyrotropin, and drug-induced thyroid dysfunction, are also important causes. The diagnosis of hyperthyroidism is generally straightforward, with raised serum thyroid hormones and suppressed serum thyrotropin in almost all cases. Appropriate treatment of hyperthyroidism relies on identification of the underlying cause. Antithyroid drugs, radioactive iodine, and surgery are the traditional treatments for the three common forms of hyperthyroidism. Beta-adrenergic blocking agents are used in most patients for symptomatic relief, and might be the only treatment needed for thyroiditis, which is transient. The more unusual causes of hyperthyroidism, including struma ovarii, thyrotropin-secreting tumours, choriocarcinoma, and amiodarone-induced thyrotoxicosis are, more often than not, a challenge to diagnose and treat.

Perioperative management of the thyrotoxic patient

Preoperative thyrotoxicosis is a potentially life-threatening condition that requires medical intervention before surgery. Most patients are undergoing thyroidectomy for persistent thyrotoxicosis, usually Graves' disease, either having contraindications to or failing medical therapy. Fewer patients are undergoing nonthyroidal surgery that is likely urgent or emergent. The choice of treatment depends on the time available for preoperative preparation, the severity of the thyrotoxicosis, and the impact of any current or previous therapies. Generally treatment is directed at a combination of targets in the thyroid hormone synthetic, secretory, and peripheral pathway with concurrent treatment to correct any decompensation of normal homeostatic mechanisms. Thionamides are the preferred initial treatment unless contraindicated, but do require several weeks to render a patient euthyroid. beta-Blockers should always be used unless absolutely contraindicated because they improve thyrotoxic symptoms especially of the cardiovascular system. Other agents including iodine and steroids can be used if rapid preparation is required or more severe thyrotoxicosis is present. The goal of therapy is to render the patient as close as possible to clinical and biochemical euthyroidism before surgery. Overall, the morbidity and mortality of adequately prepared patients is low.

Perioperative evaluation and management of the patient with endocrine dysfunction

Whenever possible, endocrine disorders should be identified and evaluated prior to surgery. A plan for perioperative management of diabetes should be based on the type of diabetes, what diabetes medications are taken, the status of diabetes control, and what type of surgery is planned. Perioperative management of diabetes must include bedside glucose monitoring. Patients with mild hypothyroidism can safely proceed with elective surgery. Elective surgery should be postponed for patients with moderate or severe hypothyroidism. Patients who have mild hyperthyroidism can undergo elective surgery with preoperative beta blockade. Elective surgery should not be done on patients with moderate or severe hyperthyroidism until they are euthyroid. Patients with pheochromocytoma need to be identified and properly treated before surgery to prevent perioperative cardiovascular complications. Patients who take endogenous steroids should have the status of their HPA axis determined prior to surgery. If the patient is undergoing moderate or major surgical stress and has documented or presumed HPA suppression, then stress doses of steroids should be give perioperatively.

Preparation with iopanoic acid rapidly controls thyrotoxicosis in patients with amiodarone-induced thyrotoxicosis before thyroidectomy

BACKGROUND

Amiodarone-induced thyrotoxicosis (AIT) may develop either in apparently normal glands (type II AIT) or in the presence of thyroid abnormalities (type I AIT). Sometimes AIT is resistant to conventional treatment. Thyroidectomy was used in patients with AIT, but in patients who are thyrotoxic it may be hazardous. METHODS; Seven patients with AIT (6 type I and 1 type II, 5 men, 2 women, mean age 70 years [range, 60-82 years]) were prepared for total thyroidectomy with a short course of iopanoic acid (1 g/day orally for a mean of 13 days), an oral iodinated cholecystographic agent inhibiting 5'-deiodinase and causing a reduction in the peripheral conversion of thyroxine to triiodothyronine. Mean thyroid volume was 64 mL (range, 10-145 mL).

RESULTS

Mean serum-free triiodothyronine levels decreased from 20 +/- 16.7 pmol/L to 6 +/- 2 pmol/L (P =.0004), whereas serum-free thyroxine values remained unchanged. Euthyroidism was rapidly (7-20 days) restored, allowing an uncomplicated total thyroidectomy in all patients and the ability to continue amiodarone therapy in 6 patients. None had increased surgical bleeding, recurrent nerve palsy, or hypoparathyroidism. No cardiovascular complications occurred.

CONCLUSIONS

Iopanoic acid is an effective drug allowing rapid control of hyperthyroidism in AIT.

Iopanoic acid rapidly controls type I amiodarone-induced thyrotoxicosis prior to thyroidectomy

Amiodarone-induced thyrotoxicosis (AIT) may develop either in apparently normal thyroid glands (Type II AIT) or in the presence of sub-clinical thyroid abnormalities (either autonomous goiter or latent Graves' disease; Type I AIT). Mixed forms also occur. While Type I AIT is due to iodine-induced excess thyroid hormone synthesis, Type II AIT is a form of amiodarone (possibly iodine) -induced destructive thyroiditis. Type I AIT is usually treated by combined thionamide and potassium perchlorate therapy, but may be resistant to therapy. On the other hand, Type II AIT often responds favorably to glucocorticoids and may not require further therapy once euthyroidism has been restored. Not infrequently, however, AIT (especially Type I) is resistant to conventional treatment, and several weeks or months may elapse before euthyroidism is restored. Thyroidectomy has been carried out in Type I AIT patients, but thyroid surgery in thyrotoxic patients, especially those with underlying cardiac problems, carries a high surgical risk. In this study we describe 3 patients with Type I AIT, who were successfully treated with a short course of iopanoic acid (IOP), an oral cholecystographic agent, which is rich in iodine and is a potent inhibitor of 5'-deiodinase, resulting in a marked decrease in the peripheral tissue conversion of T4 to T3, in preparation for thyroid surgery. Euthyroidism was rapidly restored in 7-12 days, allowing a subsequent safe and uneventful thyroidectomy in all cases. These patients were then treated with L-T4 for their hypothyroidism and amiodarone was safely re-instituted. We suggest that IOP is the drug of choice in the rapid restoration of euthyroidism prior to definitive thyroidectomy in patients with drug resistant Type I AIT.

The use of oral radiographic contrast agents in the management of hyperthyroidism

Oral iodinated radiographic contrast agents such as ipodate and iopanoic acid form an important part of the armamentarium used to treat hyperthyroidism. They rapidly and dramatically reduce serum triiodothyronine (T3) levels by inhibiting conversion of thyroxine (T4) to T3 in the periphery and by blocking secretion from the thyroid. Potential risks from the large iodine load resulting from their use limit their widespread applicability. In addition, they are ineffective when used alone on a long-term basis. However, these agents may be especially useful in treating thyrotoxic patients preoperatively, in neonatal Graves' disease, in massive levothyroxine ingestion, and when other conventional antithyroid drugs are unsuccessful or contraindicated.

Management of a pregnant patient with Graves' disease complicated by thionamide-induced neutropenia in the first trimester

A 31-year-old woman presented with neutropenia due to thionamide drug therapy for Graves' disease. She also reported 8 weeks of amenorrhoea and had a positive pregnancy test. Her drug therapy was discontinued and her neutropenia resolved uneventfully. The hyperthyroidism recurred a week later. After consideration of all treatment options, it was decided to observe until 14 weeks when an elective thyroidectomy was planned. Mother and fetus were monitored closely and both tolerated moderate hyperthyroidism well. At 14 weeks the patient underwent a total thyroidectomy after rendering her euthyroid with a short course of sodium ipodate. Labour was induced at 41 weeks. Delivery was complicated by fetal distress and precipitated a forceps delivery. A 3250 g male infant was born with poor Apgar score and required 2 h of ventilation. At 1 year, the child had reached all developmental milestones at appropriate times. Both mother and fetus may tolerate moderate thyrotoxicosis well in early pregnancy, an alternative that should be considered when thionamide drug therapy is contraindicated.

Antithyroid drugs for the treatment of hyperthyroidism caused by Graves' disease

Therapy for Graves' disease is not straightforward and often involves complex decision making. Long-term antithyroid drug therapy is appealing because it is nonablative, but it is not for everyone. The physician must weigh the advantages and disadvantages of antithyroid drug treatment and help the patient arrive at an individualized therapeutic strategy that is appropriate and cost-effective.

The Medical Management of Graves’ Disease

There are many different approaches to treat Graves' hyperthyroidism. Medical therapy is used short-term to prepare patients for radioiodine or surgery, or it is used long term with the hope of achieving a remission. b-adrenergic blocking agents are useful in all patients without a contraindication, especially selective long-acting agents such as atenalol. Thionamides are the mainstay of medical treatment. Methimazole is more potent, may be used as a single daily dose, and may have less toxicity than PTU. Severe hyperthyroidism or thyroid storm may be treated with methimazole and ipodate. Patients are prepared for surgery with methimazole and SSKI, or b-adrenergic blocking agents and ipodate.

Thyrotoxicosis factitia in a post-aortocoronary bypass patient

A 52-yr-old man presented with an evolving myocardial infarction and unstable angina. Previously, he had undergone aortocoronary bypass surgery for triple vessel disease and at that time was diagnosed as hypothyroid. He had been refractory to thyroxine treatment and now required 0.3 mg thyroxine daily. On admission, he was hypertensive, tachycardic and found to be thyrotoxic secondary to excess thyroid hormone ingestion. Treatment with iopanoic acid was started. Despite medical therapy he continued to have unstable angina. Coronary angiography confirmed further triple vessel disease with blockage to his previous grafts. He was taken to surgery for coronary revascularization. On arriving in the intensive care unit he developed a thyroid storm. His temperature increased from 36.5 to 39.5 degrees C requiring a cooling blanket and cold irrigation down a nasogastric tube. An esmolol infusion was started to control his persistent tachycardia but this depressed his myocardial contractility. He required amrinone and noradrenaline infusions as further inotropic support. For sedation and muscle relaxation, intravenous propofol infusion and doxacurium were given. Over the following 20 hr the patient's condition stabilized. In conclusion, we describe the use of a short-acting beta blocker to avoid compromising an impaired myocardium during a thyroid storm which we could stop if the patient's cardiac condition deteriorated. In addition, amrinone, a phosphodiesterase inhibitor, was our inotrope of choice as it does not act on the already blocked beta adrenergic system.