ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: J Clin Endocrinol Metab. 2019;104:5540–5546.

This single center, retrospective study analyzed the prevalence and natural history of amiodarone associated thyroid disease in 190 children and young adults with detailed thyroid function tests. Amiodarone induced hypothyroidism (AIH) and thyrotoxicosis (AIT) are well known entities due to direct thyroid toxicity. Further, subclinical hypothyroidism (SCH) is caused by amiodarone induced inhibition of T4-to-T3 conversion, thereby stimulating TSH, and resulting in high FT4 but low-normal T3, as summarized in a recent detailed review on drug effects on the thyroid [1]. In their cohort, Barrett et al. observed thyroid abnormalities in one third of patients (SCH 17%, AIH 14%, AIT 2%). Sixteen percent of all amiodarone exposed patients developed persistent thyroid disease (SCH 9/33, AIH 18/26, AIT 3/4). While AIT occurred within the first two weeks, AIH and SCH incidence plateaued at 5 weeks after start of therapy. Amiodarone therapy for longer than ten days increased the risk for SCH and AIH. A final important result was that, despite the single center design, only 40% of all amiodarone treated patients received thyroid function testing, while in a national study this proportion was reported to be as low as 12% [2].

This important paper describes the incidence and prognosis of amiodarone induced thyroid diseases in a large retrospective cohort. Based on their findings, the authors provide recommendations for systematic thyroid function testing in patients before and weekly for 5 weeks after treatment start to screen for SCH, AIH and AIT. To establish these recommendations, pediatric cardiologists will need to be informed about these new data and be involved in establishing standard operating procedures.

Reference:

1. Burch HB. Drug effects on the thyroid. N Engl J Med. 2019;381:749–761.2. Moffet BS, Valdes SO, Kim JJ. Amiodarone monitoring practices in pediatric hospitals in the United States. Pediatr Cardiol. 2013;34:1762–1766.