Amiodarone-induced hyperthyroidism and a thyroid nodule

To report two cases of thyrotoxicosis associated with amiodarone therapy and to discuss how the presence of a thyroid nodule alters management.

We describe two patients with amiodarone-induced hyperthyroidism, review the mechanisms of disease, and outline a strategy for decision making relative to treatment in the presence of a thyroid nodule.

Amiodarone-induced thyrotoxicosis occurs by two mechanisms: a direct toxic effect and iodine loading. This condition may be treated medically or surgically, but when discontinuation of amiodarone therapy is not possible and medical management is ineffective, surgical therapy is often necessary. The optimal presurgical management in the cases described required the use of thyroid scanning to determine whether the disease process was attributable to a hyperfunctioning nodule or generalized. The findings were helpful in planning the extent of surgical excision.

When surgical treatment is planned for patients with a solitary thyroid nodule and amiodarone-induced hyperthyroidism, preoperative thyroid scanning will direct the surgeon to perform either subtotal thyroidectomy for diffuse disease or lobectomy for a hyperfunctioning nodule.