Annals of Internal Medicine | Hyperthyroidism
Ann Intern Med. 3 July 2012;157(1):ITC1-1
Hyperthyroidism is a clinical state characterized by excessive serum concentrations of thyroxine (T4), triiodothyronine (T3), or both with suppression of serum thyroid-stimulating hormone (TSH) levels. Some observers prefer the term thyrotoxicosis for this condition and restrict the term hyperthyroidism to the types of thyrotoxicosis that are caused when the thyroid gland synthesizes and secretes too much thyroid hormone. To avoid confusion, however, we will consider hyperthyroidism and thyrotoxicosis to be the same and will use only the term hyperthyroidism.