Refractory amiodarone-associated thyrotoxicosis: an indication for thyroidectomy

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.

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.

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.

Anesthetic considerations in a patient with amiodarone-induced thyrotoxicosis

Amiodarone-induced thryrotoxicosis (AIT) is a rare but serious complication of amiodarone use, especially in patients with severe cardiac disease. We present a patient who developed AIT, following administration of amiodarone for life-threatening ventricular arrhythmias. We discuss the medical management of AIT and anesthetic considerations for management of patients with thyrotoxicosis and severe cardiac disease who require surgery including thyroidectomy.

Surgical management of amiodarone-induced thyrotoxicosis in a patient with Eisenmenger's syndrome: literature review and case report

OBJECTIVE

We present a patient with a rare combination of amiodarone-induced thyrotoxicosis and Eisenmenger's syndrome.

METHOD

Case report and review of the world literature regarding the morbidity and mortality of surgical management of amiodarone-induced thyrotoxicosis and the potential hazards of non-cardiac surgery in patients with Eisenmenger's syndrome.

RESULTS

Failure of maximal medical therapy necessitated surgical management to treat amiodarone-induced thyrotoxicosis which, in this particular patient, carried significant risks. Total thyroidectomy was performed leading to rapid resolution of thyrotoxicosis, and the patient made an uncomplicated recovery. We present this case because of its rarity and the potentially hazardous nature of surgical intervention in patients with Eisenmenger's syndrome. The pathogenesis of amiodarone-induced thyrotoxicosis and the differing approaches of medical and surgical management are discussed.

CONCLUSION

Based on our findings, we propose that surgical management should be considered earlier in the treatment algorithm (or possibly as first-line therapy) for amiodarone-induced thyrotoxicosis.

Surgical considerations for treatment of amiodarone-induced thyrotoxicosis

PURPOSE

We present our experience with surgical management of amiodarone-induced thyrotoxicosis, including preoperative, intraoperative, and postoperative considerations.

METHODS

Retrospective review of the medical records and the histological slides and a Medline search of amiodarone and thyroid gland.

CONCLUSIONS

Amiodarone is a drug used to treat potentially lethal ventricular arrhythmia. One of the known side effects is thyroid dysfunction. In patients who cannot safely discontinue amiodarone or when medical therapy is ineffective in controlling thyrotoxicosis, thyroidectomy is the treatment of choice.

Histopathology of the thyroid in amiodarone-induced hypothyroidism

Amiodarone is well recognized as an anti-arrhythmic drug containing a high dose of iodine with considerable potential to cause thyroid dysfunction. The present patient was a 66-year-old Japanese woman who developed a cardiac arrhythmia and was given amiodarone as an anti-arrhythmic agent for approximately 3 months, until the day before her death. However, 19 days after starting amiodarone, serum testing indicated a hypothyroid status that was not recognized clinically. At autopsy, microscopy showed that most of the thyroid follicles were enlarged with dense colloid substance and lined by flattened follicular cells (involuted follicles). There were a small number of damaged follicles infiltrated by macrophages, which were immunopositive for HAM56. Sudan IV staining indicated many lipid droplets in follicular cells. Ultrastructurally the follicular cells contained large residual bodies composed of abundant electron-lucent lipid droplets of variable size. Although it is difficult to be certain of the direct link of amiodarone on the basis of a single case, it is reasonable to presume that this histopathology is associated with amiodarone-induced hypothyroidism and that involution changes represent the hypofunctional status of this drug-induced disorder. This is the first report on the histopathological findings of thyroid tissue from a patient with amiodarone-induced hypothyroidism.

Total Thyroidectomy for Amiodarone-associated Thyrotoxicosis in Patients with Severe Cardiac Disease

BACKGROUND

Surgical treatment of amiodarone-associated thyrotoxicosis (AAT) is effective although fewer than 100 cases have been reported world wide.

MATERIALS AND METHODS

We reviewed 14 patients treated with total thyroidectomy by a single surgeon from 1998 to 2005.

RESULTS

There were 11 male and 3 female patients who ranged in age from 26 to 82 years (average 50.5). Nine patients refractory to medical management and 5 in whom amiodarone needed to be continued were treated surgically. Ten patients developed thyrotoxicosis while being treated with amiodarone, but 4 became thyrotoxic after ceasing amiodarone 2, 2, 6 and 13 months previously. One patient recently had a cardiac transplant, and 4 were on the active cardiac transplant waiting list. Cardiac ejection fractions ranged from 15% to 50% (average 39%). Four patients had serious complications from medication used to control thyrotoxicosis, including one case of agranulocytosis from carbimazole. Total thyroidectomy was performed under general anaesthesia with no significant intraoperative complications and no deaths. There were no recurrent laryngeal nerve injuries. Two patients required short-term calcium supplementation. All patients had rapid resolution of their symptoms and were euthyroid on thyroxine postoperatively. Two patients had such improvement they were removed from the cardiac transplant list.

CONCLUSIONS

Despite severe cardiac disease, total thyroidectomy can be performed successfully under general anaesthesia. Surgery should be considered early in the treatment plan. Surgery is particularly appropriate where it is considered necessary to continue amiodarone, when there are complications from the medications used to treat thyrotoxicosis and to facilitate fitness for or defer the need for cardiac transplantation.

O uso de carbonato de lítio no tratamento da tireotoxicose induzida por amiodarona

Dentre as disfunções tireoidianas induzidas por amiodarona, a tireotoxicose é a mais grave e associada a maior morbi-mortalidade. O tratamento consiste no emprego de altas doses de drogas antitireoidianas e corticoesteróides, de forma isolada ou combinada. Outras terapias associadas foram propostas para o tratamento dos casos refratários. Relatamos o caso de um paciente de 40 anos com história de miocardiopatia dilatada idiopática que desenvolveu um quadro grave de tireoidite induzida por amiodarona após transplante cardíaco. Este paciente não respondeu à terapia inicial com doses altas de droga antitireoidiana e corticoesteróides, sendo, então, associado o carbonato de lítio em baixas doses e por curto período de tempo, o que resultou na normalização da função tireoidiana. Neste caso, o emprego do carbonato de lítio mostrou-se como uma terapia adjuvante eficaz e segura no controle da tireotoxicose induzida por amiodarona.

Surgical Management of Amiodarone-associated Thyrotoxicosis: Mayo Clinic Experience

Amiodarone-associated thyrotoxicosis (AAT) is often poorly tolerated owing to underlying cardiac disease, and it is frequently refractory to conventional medical treatment. The goal of this study was to describe the patient characteristics, management, and outcomes of all the patients treated surgically for AAT at a single institution. We conducted a retrospective chart review of all patients managed surgically for AAT (April 1985 through November 2002) at the Mayo Clinic in Rochester, Minnesota. Altogether, 29 men and 5 women, ages 39 to 85 years (median 60 years), treated with amiodarone for 3 to 108 months underwent near-total or total thyroidectomy. Frequent symptoms were worsening heart failure, fatigue, weight loss, and tremor. Altogether, 12 patients failed medical management of their AAT, and 21 received no preoperative medical therapy. One patient had been successfully managed medically but required definitive treatment. Common indications for operation were the need to remain on amiodarone, cardiac decompensation, medically refractory disease, and severe symptoms, both hyperthyroid and cardiac, necessitating prompt resolution. The median+/-SD American Society of Anesthesiologists (ASA) classification (1 = healthy through 5 = moribund) was 3.00+/-0.58. A total of 27 specimens had histology consistent with AAT. Complications included death (n = 3), rehospitalization (n = 3), symptomatic hypocalcemia (n = 2), pneumonia (n = 2), cervical hematoma (n = 1), prolonged ventilatorywean (n = 1), and stroke (n = 1); one patient developed hypotension, adult respiratory distress syndrome, and sepsis. Of the 31 surviving patients, 25 (80%) remained on amiodarone postoperatively. The median follow-up was 29 months, at which time all surviving patients were free of hyperthyroid symptoms. Thyroidectomy is an effective treatment for AAT but has a high incidence of perioperative morbidity and mortality. The cardiovascular co-morbidities and high operative risk in this group of patients may account for the increased complication rate.

[Anaesthesia and amiodarone-associated hyperthyroidism]

Amiodarone can induce severe hyperthyroidism that justifies its withdrawal and initiation of antithyroid drugs. Impossibility to stop amiodarone, failure to control hyperthyroidism and unfavourable evolution can lead to thyroidectomy. Cardiac manifestations, persistence of hyperthyroidism and interactions between amiodarone and anaesthetic or haemodynamic drugs may contraindicate anaesthesia. We report nine consecutive cases of amiodarone-associated hyperthyroidism that prompted us to perform thyroidectomy under general anaesthesia. The features and anaesthetic data of patients were noted. The antithyroid medical treatment failed in all patients. After thyroidectomy, evolution was favourable in all nine cases, without any intra or postoperative complication, in spite of the extent of hyperthyroidism and the severity of the associated cardiac problems. Despite potential high risks, thyroidectomy for amiodarone-induced hyperthyroidism does not seem to increase morbidity or mortality and allows a quick return to euthyroidism and reintroduction of amiodarone.

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

BACKGROUND

Amiodarone-induced thyrotoxicosis (AIT) presents a therapeutic challenge because of its resistance to standard antithyroid therapy. In iodine-deplete environments, colour-flow Doppler sonography (CFDS) has allowed distinction between two types of AIT: (i) Type I AIT, associated with increased vascularity (CFDS I-III) and response to thionamide antithyroid drug and (ii) type II AIT, with no/little thyroid vascularity (CFDS 0) and prednisolone responsiveness.

AIM

To clarify if CFDS patterns correlated with treatment outcomes in a retrospective study of 24 patients with AIT in an iodine-replete environment.

METHODS

Medical records of patients who presented to a teaching hospital between January 1998 to December 2000 were reviewed. Results of CFDS, ultrasound measurement of thyroid size and technetium scanning of the thyroid were correlated with treatment responses, especially prednisolone responsiveness.

RESULTS

Thirteen of 24 patients showed CFDS 0. Twelve of these 13 were evaluable for prednisolone responsiveness, of whom seven (58%) were prednisolone-responsive. Of 11 patients with CFDS I-III, four (36%) responded to antithyroid medication alone and only one of seven (14%) was prednisolone-responsive. Euthyroidism was achieved twice as rapidly in patients with CFDS 0 than those with CFDS I-III. Because of medical treatment failure, seven patients, from both CFDS groups, required urgent near-total thyroidectomy which was successful and uncomplicated in all cases.

CONCLUSIONS

CFDS is useful in the management of AIT because CFDS 0 correlates better with prednisolone response (58%) than CFDS I-III (14%). However, unlike experience in iodine-deficient regions, the results of the present study revealed that treatment responses to thionamide or prednisolone were heterogeneous within uniform CFDS patterns. Thus, prednisolone--responsiveness was not consistently predicted by CFDS 0, but the presence of flow appeared to correlate with non-response to prednisolone.

Inflammatory thyroid disorders

Inflammatory thyroid disorders encompass a broad spectrum of diseases that are generally self-limited, and relatively easy to diagnose and manage. Autoimmune subtypes are by far the most commonly encountered diagnoses and create the most confusion because of simultaneous overlap and the potential for interconversion among the subtypes. The otolaryngologist will frequently see these disorders and provide valued consultative care and surgical intervention as needed.

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.

Superior limbic keratoconjunctivitis: multifactorial mechanical pathogenesis

Origins of superior limbic keratoconjunctivitis (SLK) are not well understood. Prompted by suggestions that pressure and friction may contribute to SLK, this paper, using evidence from the literature and from personal Kodachrome records, aims to assess, and if appropriate, enhance this understanding. The survey disclosed evidence confirming mechanical aetiology. Support is presented for the notion that SLK arises from soft tissue microtrauma: (i) between tarsal and bulbar surfaces; and (ii) between conjunctival stroma and sclera. In each pair the two apposed tissues are in repetitive motion relative to each other. It is concluded that SLK arises because nonstandard combinations of multiple predisposing and/or trigger factors exceed the physiological tolerance of mechanical stresses upon the ocular surface and tissues. Through their effects on particular tissues, eight separate stressing forces were perceived. The many contributing factors in four categories are integrated into a new aetiologic concept.