Disseminated Thyroid Autonomy or Graves' Disease: Reevaluation by a Second Generation TSH Receptor Antibody Assay

The clinical diagnosis of disseminated autonomy (DISA) can only be established by exclusion of Graves' disease (GD). Both hyperthyroid conditions share the same scintigraphic appearance and can only be distinguished from each other clinically either by the presence or absence of endocrine ophthalmopathy (EO) or thyrotropin (TSH) binding inhibiting immunoglobulins (TBIIs). The purpose of this study was the reevaluation of thyroid autonomies originally classified as DISAs by a second-generation radioreceptor antibody assay (RAA) (DYNOtest® TRAKhuman) (B.R.A.H.M.S. Diagnostika, Berlin, Germany). The analysis included 32 patients (female: n = 25, male: n = 7; mean age: 46 ± 18 years) who were initially diagnosed with DISA. All patients were TSH receptor (TSHR) antibody (TRAb) negative by a conventional radioimmunoassay (RIA) (TSH-REZAK® RIA) (Medipan Diagnostica, Selchow, Germany) during their first evaluation. The presence of EO was excluded by clinical signs in all patients. Surgery had been performed prior to our evaluation in 5 patients and after our survey in 1 patient. Four patients had been treated previously with 131 I. Ten patients were treated with thionamides during our evaluation, and 13 had not been treated before. One hundred three patients who had either healthy thyroids, nontoxic goiters, or focal autonomies served as controls and were evaluated both by the TSH-REZAK® assay and the DYNOtest® TRAKhuman assay. Seven of thirty-two (22%) patients originally classified as DISA were TRAb positive in the second-generation assay. In this group, 5 of 7 patients had a total thyroid volume (TTV)