Incidence and Pattern of Thyroid Dysfunction in Patients on Chronic Amiodarone Therapy: Experience at a Tertiary Care Centre in Oman

Farhan, Hatem; Albulushi, Arif; Taqi, Aqila; Al-Hashim, Abdulhakeem; Alsaidi, Khalid; Al-Rasadi, Khalid; Al-Mazroui, A.; Al‐Zakwani, Ibrahim

doi:10.2174/1874192401307010122

Cited by 11 publications

(7 citation statements)

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“…Amiodarone administration has been reported to cause thyroid dysfunction in 15% to 20% of cases [ 1–3 ], with the incidence of thyrotoxicosis being ~3% to 9% [ 3–5 ]. Although amiodarone-induced hypothyroidism is more common in iodine-replete regions such as North America, the less commonly encountered entity of amiodarone-induced thyrotoxicosis (AIT) is universally recognized as a difficult diagnostic and management challenge, at times leading to life-threatening complications.…”

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confidence: 99%

Thyroidectomy for Amiodarone-Induced Thyrotoxicosis: Mayo Clinic Experience

Kotwal

Clark

Lyden

et al. 2018

Journal of the Endocrine Society

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ContextAmiodarone-induced thyrotoxicosis (AIT) is a difficult diagnostic and management challenge, especially during severe thyrotoxicosis accompanied by cardiovascular compromise.ObjectiveTo evaluate thyroidectomy for the management of AIT.DesignRetrospective cohort study of adults with noncongenital heart disease with AIT after >3 months of amiodarone who underwent thyroidectomy from 1 November 2002 to 31 December 2016.SettingReferral center.PatientsThe group was comprised of 17 patients.Main Outcome MeasuresThyroid function, left ventricular ejection fraction (LVEF), and surgical complications were the main outcome measures.ResultsPatients had median age of 60 years, 82.4% were male, and 47% had systolic heart failure. At diagnosis, median TSH was 0.005 mIU/L, median free T4 was 3.25 ng/dL, and total T3 was 198.5 ng/dL. We classified five patients as type 1 and type 2 and two patients as mixed; five patients remained undefined. The most common surgical indications were medically refractory disease, worsening cardiac status, and severe thyrotoxicosis requiring prompt resolution. Within 1 week post-thyroidectomy, median TSH was 0.565 mIU/L, and free T4 was 1.8 ng/dL. Median LVEF improved by 8% in patients with systolic heart failure. Seven patients had a complication within 30 days postsurgery (rehospitalization, n = 4; cervical hematoma, n = 2; recurrent arrhythmia, n = 2; symptomatic hypocalcemia, n = 1; death, n = 1). A larger thyroid gland was a risk factor for complications.ConclusionsThyroidectomy resulted in rapid resolution of thyrotoxicosis. Its complication rate was higher than for non-AIT indications but lower than previously reported in a similar population of high-risk surgical patients.

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confidence: 99%

Thyroidectomy for Amiodarone-Induced Thyrotoxicosis: Mayo Clinic Experience

Kotwal

Clark

Lyden

et al. 2018

Journal of the Endocrine Society

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“…Farhan ve ark. 'larının [26] 59 hastanın retrospektif olarak incelendiği Umman populasyonunda ise hastaların %19'unda TD saptanmış. AIH %12, AIT %5 oranın-da izlenmiş.…”

Section: İstatistiksel Analizunclassified

Short-Term effects of amiodarone on thyroid function on Aegean region population of Turkey: A prospective regional and observational study

Acet

Ertaş²

2014

J Clin Exp Invest

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Objective: We aimed to investigate short term effects of oral and infusion dosages of amiodarone on thyroid function. Methods:A hundred and fifty-five prospectively consecutive patients with a diagnosis of atrial or ventricular arrhythmias admitted to our clinic whom amiodarone were applied enrolled to our study. 134 patients received 16 mg/kg amiodarone iv infusion for 24 hours and oral 500±100 mg/day amiodarone as the maintenance dose for one month. 21 patients received only oral 500±100 mg/day amiodarone dose for one month. Follow up visit was performed in the first month of amiodarone therapy. Results:In this study 68% of patients were male and the average age of the patients was 62.8±13.5. The indications for amiodarone treatment were atrial fibrillation (41%), ventricular tachycardia (41%), and preoperative (5%), supraventricular tachycardia (5%), atrial flutter (5%), and ventricular fibrillation (3%). At the first month of follow up 83% of patients were in euthyroid state, 17% of the patients had amiodarone induced thyroid dysfunction (TD), 5% of patients had subclinical hyperthyroidism, 5% of patients had manifest hypothyroidism, 7% of patients had subclinical hyperthyroidism, and 1% of the patients developed overt hyperthyroidism. Conclusion:In this study we showed that amiodarone can cause adverse effects on thyroid function in a short time of period. For this reason patients should be followed in the first, third, sixth and twelfth months of amiodarone therapy and thyroid function should be evaluated. J Clin Exp Invest 2014; 5 (2): 280-285Key words: Amiodarone, thyroid dysfunction, prospective study ÖZET Amaç: Bu yazıda amiodaronun tiroid fonksiyonları üze-rindeki kısa dönem etkilerini, oral ve infüzyon dozlarınının tiroid fonksiyonları üzerindeki etkisini araştırmak amaç-lanmıştır.Yöntemler: Kliniğimize atrial ve ventriküler aritmilerle başvurup amiodaron başlama endikasyonu olan ardışık 155 ötroid hasta çalışmaya alındı. Hastaların 134'üne 16 mg/kg dozunda 24 saat IV amiodaron infüzyonu takiben bir ay boyunca oral 500±100 mg/gün, geriye kalan 21 hastaya ise sadece oral 500±100 mg/gün amiodaron baş-landı. Hastalar tedavinin birinci ayında kontrole çağrıldı. Bulgular: Çalışmaya alınan hastaların %68'i erkek olup hastaların ortalama yaşı. 62,8±13,5 idi. Amiodaron baş-lama endikayonu olan hastaların %41'i atrial fibrilasyon, % 41'i ventriküler taşikardi, %5'i preoperatif, %5'i supraventriküler taşikardi, %5'i atriyal flutter, %3'ü ventriküler fibrilasyondu. Birinci ay kontrolünde %83 hastada ötiroid durum, % 17 hastada ise amiodarona bağlı tiroid disfonksiyonu (TD) saptandı. TD saptanan hastaların %5'i subklinik hipotiroidi, %5'i aşikar hipotiroidi, %7'si subklinik hipertiroidi, %1'inde de aşikar hipertiroidi gelişmişti. Sonuçlar: Bu çalışmada amiodaronun kısa dönemde de tiroid fonksiyonları üzerinde olumsuz etki yapabileceğini gösterdik. Bu nedenle amiodaron tedavisi başlanan hastalar birinci ay, üçüncü ay, altıncı ay ve onikinci ay kontrole çağrılmalıdır. Böylece amiodaron tedavisi alması zoru...

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“…Amiodarone-induced thyrotoxicosis (AIT) has been associated with increased mortality in older individuals with impaired ventricular function [1], underlying the importance of rapid restoration and maintenance of euthyroidism in this condition. Amiodarone has been reported to cause thyroid dysfunction in 15-20% of cases [1][2][3], with the incidence of thyrotoxicosis being approximately 5% [3,4]. Plasmapheresis as a treatment option for thyrotoxicosis refractory to medical therapy has shown mixed results.…”

Section: Introductionmentioning

confidence: 99%

Mixed Amiodarone-Induced Thyrotoxicosis Refractory to Medical Therapy and Plasmapheresis

et al. 2015

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Amiodarone-induced thyrotoxicosis (AIT) is associated with increased mortality in older individuals with impaired ventricular function, underlying the importance of rapid restoration and maintenance of euthyroidism. Plasmapheresis for treating thyrotoxicosis has shown mixed results. A 61-year-old gentleman was hospitalized for progressively worsening dyspnea, palpitations, tremor and generalized weakness. He had a history of atrial fibrillation, coronary artery disease, heart failure and type 2 diabetes. He had been diagnosed with AIT 4 months prior to admission, after which amiodarone was discontinued, and he was started on prednisone and methimazole which was later changed to propylthiouracil. Physical examination revealed irregular tachycardia, lid lag, fine hand tremor, proximal muscle weakness, pedal edema and a small, smooth, non-tender thyroid gland without bruit. Hormonal investigations revealed low TSH of 0.02 μIU/mL (reference: 0.28 -3.89), high free T4 of 4.88 ng/dL (reference: 0.58 -1.64), high free T3 of 5.4 pg/mL (reference: 2.5 -3.9) and normal total T3 of 114 ng/dL (reference: 87 -178). Thyroglobulin antibody, thyroid peroxidase antibody and thyroid stimulating immunoglobulin were undetectable. Echocardiogram revealed reduced left ventricle ejection fraction of 25%. Ultrasound showed a bilaterally heterogeneous, hypovascular and hypoechoic thyroid. I-123 scan revealed very low uptake. These findings were suggestive of destructive type 2 AIT. However, the lack of a good response to steroids argued for type 1 AIT. Given his poor response to medical therapy and increased cardiovascular risk for an urgent thyroidectomy, plasmapheresis was instituted in an attempt to lower the thyroid hormone levels. Eight daily cycles provided only modest clinical and biochemical improvement. Subsequently, he underwent total thyroidectomy leading to improvement of thyrotoxicosis. Histopathology of the thyroid demonstrated intrafollicular histiocytes, patchy fibrosis and involuted follicles, suggestive of destructive thyroiditis. On follow-up 2 months later, he remained clinically euthyroid on levothyroxine replacement with stable cardiac status. This case represents mixed/indeterminate AIT of protracted duration refractory to thionamides and steroids. Plasmapheresis did not provide clinical improvement and only modestly lowered the free T4 level. Euthyroidism was finally achieved following total thyroidectomy. This finding suggests the limitations of utilizing plasmapheresis as a therapeutic modality prior to definitive treatment in AIT.

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Incidence and Pattern of Thyroid Dysfunction in Patients on Chronic Amiodarone Therapy: Experience at a Tertiary Care Centre in Oman

Cited by 11 publications

References 29 publications

Thyroidectomy for Amiodarone-Induced Thyrotoxicosis: Mayo Clinic Experience

Thyroidectomy for Amiodarone-Induced Thyrotoxicosis: Mayo Clinic Experience

Short-Term effects of amiodarone on thyroid function on Aegean region population of Turkey: A prospective regional and observational study

Mixed Amiodarone-Induced Thyrotoxicosis Refractory to Medical Therapy and Plasmapheresis

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