Graves' Disease

A 23-year-old woman has palpitations. Over the past 6 months, she has had a 10-lb (4.5-kg) weight loss. Her pulse is 119 beats per minute, and blood pressure is 137/80 mm Hg. Her thyroid gland is diffusely enlarged. She has eyelid lag but no proptosis. The level of thyrotropin is 0.02 μU per ml (normal range, 0.35 to 4.50), and free thyroxine is 4.10 ng per deciliter (normal range, 0.89 to 1.76). How should she be further evaluated and...