Surgical management of amiodarone-associated thyrotoxicosis

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.

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.

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.

Management of amiodarone-induced thyrotoxicosis

Thyrotoxicosis occurs in up to 3% of people prescribed amiodarone in the UK. The management of amiodarone-induced thyrotoxicosis remains a clinical challenge, as data on optimal treatment from controlled trials are not available. This review will focus on current lines of management.