Q. A 55-year-old woman with a history of hypothyroidism presents to the emergency department with symptoms of sweating, tachycardia, restlessness, diarrhea, heat intolerance, and insomnia. She reports that she recently started taking iodine supplements on the advice of a friend, as she heard it could help with her hypothyroidism. Physical examination reveals a heart rate of 110/min and a blood pressure of 150/90 mm Hg. The patient appears anxious and restless. You detect diffuse goiter and a slightly enlarged thyroid gland. Based on her history and physical examination, what is the most likely diagnosis?