Diagnosis and Clinical Course of Three Adolescents with Amiodarone-Induced Hyperthyroidism

Amiodarone-induced hyperthyroidism is a known side effect of amiodarone treatment. In the pediatric population, long-term amiodarone treatment is rarely indicated because of its severe side effects including thyroid function impairment. Treatment is therefore restricted to therapy-resistant arrhythmias. In the literature, scarce data are available on the management and therapy of amiodarone-induced thyroid dysfunction at a young age. We present three adolescent patients developing amiodarone-induced thyrotoxicosis in the months after amiodarone therapy. A latency period for thyroid dysfunction has been described in adulthood but was not previously reported in pediatric patients. The gap between amiodarone treatment and the development of symptoms and the diagnosis of hyperthyroidism was between 3 and 10 months. In two patients, hyperthyroidism was transient and resolved without treatment. These two patients, one boy and on girl, were almost asymptomatic. In contrast, in one male patient overt and severe hyperthyroidism developed. We began treatment with thiamazole without benefit. Control of hyperthyroidism was achieved under prednisone treatment, which was continued for 9 months. Clinical evaluation proved an amiodarone-induced destructive thyroiditis in this patient. Amiodarone-induced thyroid dysfunction is frequent also in pediatric patients with long-term amiodarone treatment. Patients and clinicians should be aware of the impact of amiodarone on thyroid function during and also in the months and maybe years after treatment. Careful follow-up is needed, as symptoms might be associated with the underlying cardiac disease in these patients. Amiodarone-induced thyrotoxicosis often resolves without treatment but can be challenging in some cases.