A 72-year-old man has new-onset atrial fi brillation and abnormal results on thyroid tests (thyrotropin <> mIU/L, free thyroxine 2.3 ng/dL).

A 72-year-old man has new-onset atrial fi brillation and abnormal results on thyroid tests (thyrotropin <> mIU/L, free thyroxine 2.3 ng/dL). He begins antiarrhythmic therapy and is referred to you. He reports palpitations and weight loss for 3 months along with redness, swelling, and pain over his eyes. His past medical history is signifi cant for hypertension, congestive heart failure, and ongoing nicotine dependence. On examination, his heart rate is irregular at 92 beats per minute, his blood pressure is 148/86 mm Hg, and his lungs are clear. Th e thyroid is nontender, about twice the normal size, and increased in consistency. He has bilateral exophthalmos with red and signifi cantly swollen eyelids and injected conjunctiva. Th ere is pitting edema (trace) of the lower extremities and an area of brownish thickening of the skin over the pretibial areas. What is the best management for his thyroid dysfunction at this point? a. Observation, antiarrhythmic treatment, and reevaluation in 6 weeks for possible hypothyroidism b. Propylthiouracil (PTU) c. Methimazole treatment d. Total or near-total thyroidectomy e. Radioactive iodine treatment