Hyperthyroidism or thyrotoxicosis?

To the Editor: I read with interest the article by Perkins and colleagues, “A young pregnant woman with shortness of breath” on pages 788–792 of the November 2008 issue of the Cleveland Clinic Journal of Medicine. An incorrect meaning occurs in the article. Thyrotoxicosis is the state of symptomatic thyroid hormone excess, of both endogenous and exogenous cause. It is not synonymous with hyperthyroidism, which is the result of excessive thyroid function.