title: Subclinical hyperthyroidism: current concepts and scintigraphic imaging.
abstract: Subclinical hyperthyroidism is defined as normal serum free thyroxine and a free triiodothyronine level, with a thyroid-stimulating hormone level suppressed below the normal range and is usually undetectable. Although patients with this diagnosis have no or few signs and symptoms of overt thyrotoxicosis, there is sufficient evidence that it is associated with a relatively higher risk of supraventricular arrhythmias as well as the acceleration or the development of osteoporosis. Consequently, the approach to the patient with subclinical hyperthyroidism is controversial, that is, therapeutic intervention versus watchful waiting. Regardless, it is imperative for the referring physician to identify the causative thyroid disorder. This is optimally accomplished by a functional study, namely scintigraphy. Recognition of the scan findings of the various causes of subclinical hyperthyroidism enables the imaging specialist to help in diagnosing the underlying condition causing thyroid-stimulating hormone suppression thereby facilitating the workup and management of this thyroid disorder.
authors.affiliation: Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA. charles.intenzo@jefferson.edu
authors.forename: Charles
authors.initials: C
authors.lastname: Intenzo
authors.forename: Serge
authors.initials: S
authors.lastname: Jabbour
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Miller
authors.forename: Intekhab
authors.initials: I
authors.lastname: Ahmed
authors.forename: Kevin
authors.initials: K
authors.lastname: Furlong
authors.forename: Medina
authors.initials: M
authors.lastname: Kushen
authors.forename: Sung M
authors.initials: SM
authors.lastname: Kim
authors.forename: David M
authors.initials: DM
authors.lastname: Capuzzi
mesh_terms: D006801:Humans; D006980:Hyperthyroidism / Q000000981:diagnostic imaging*; D007457:Iodine Radioisotopes; D011877:Radionuclide Imaging / Q000379:methods*
chemical_list: D007457:Iodine Radioisotopes