A 65-year-old woman is seen for routine evaluation. She has a history of paroxysmal atrial fibrillation and osteoporosis, which has been treated with a bisphosphonate. She has no history of thyroid disease and reports no symptoms of hyperthyroidism. Her pulse is 80 beats per minute. The left thyroid lobe is enlarged, but the results of physical examination are otherwise normal, as are the results of electrocardiography. The serum thyrotropin level is 0.2 mU per liter (reference range, 0.5 to 4.5) and the free thyroxine (T4) level 1.2 ng per deciliter (reference range, 0.8 to 1.8). How should this patient be evaluated and treated?
ASJC Scopus subject areas