Introduction

Abstract

Thyrotoxicosis is a syndrome with many different etiologies, with Graves’s disease being the most common in young and middle-aged women. In the following section, we discuss three unusual cases of thyrotoxicosis to illustrate some of the diagnostic and therapeutic challenges often encountered in the clinic. The first case is of a man who was thought to have hypothyroidism and was treated with levothyroxine, but his TSH failed to suppress with escalating doses of levothyroxine. Years later, he was found to have a TSH-producing adenoma, after he presented in atrial flutter. Next, we present a case of a woman who was diagnosed with thyrotoxicosis and treated with total thyroidectomy after she became intolerant to methimazole therapy. Due to her persistent thyrotoxic state, an I-123 whole body scan identified a radioiodine-avid pelvic mass. Surgical pathology confirmed the diagnosis of struma ovarii. Finally, we present a case of a young woman who had suffered from a mysterious form of thyrotoxicosis for 18 months, before she was found to have unknowingly been consuming thyroid hormone contained in an herbal weight-loss supplement. A discussion, including the presentation, differential diagnosis, investigation, and treatment of these three uncommon causes of thyrotoxicosis follows each case.