COLOR-FLOW DOPPLER SONOGRAPHY IN THYROTOXICOSIS-FACTITIA

Color Row doppler sonography (CFDS) is a powerful technique which disp lays tissue blood flow and vascularity. Hyperthyroidism due to Graves' disease is characterized by variable degrees of increased blood flow at CFDS. The purpose of this study was to evaluate CFDS patterns in fi ve women with thyrotoxicosis factitia, a condition due to surreptitiou s ingestion of excess thyroid hormone. Diagnosis was supported by the finding of elevated free thyroxine (FT4), ranging 24.2-67.6 pmol/L (no rmal values: 8.3-20.5), elevated free triiodothyronine (FT3), ranging 9.9-26.7 pmol/L (normal values: 3.8-8.4), undetectable thyrotropin (TS H), absent anti-thyroid antibodies, undetectable serum thyroglobulin ( Tg) concentrations, very low/suppressed thyroidal radioiodine uptake a nd normal/low urinary iodine excretion. Moreover, all patients admitte d thyroid hormone pills intake. All patients had normal thyroid volume and echogenicity at conventional sonography (mean estimated volume, 9 .4 mi, range, 6-11 mi), and absent hypervascularity or minimal intrath yroidal vascular spots at CFDS. The peak systolic velocity (PSV) was a t the lower limit of normal values (mean, 4 cm/sec, range 3-5 cm/sec). Twenty-six women with untreated Graves' disease had an increase in th e mean PSV, (mean 12.9 cm/sec, range 8-20, p<0.001) and diffuse hyperv ascularity. CFDS pattern in 24 normal women residing in the same area did not differ from that found in patients with thyrotoxicosis factiti a. Thus, due to the nonthyroidal origin of excess thyroid hormone, CFD S showed absent hypervascularity and normal PSV in spite of a thyrotox ic status. These findings well correlate with the etiology of thyrotox icosis factitia and may represent an additional, useful tool to confir m the diagnosis. For its easiness, rapidity (10 min) and noninvasive f eatures, CFDS can be considered a first line test during office examin ation when thyrotoxicosis factitia is suspected. (C) 1996, Editrice Ku rtis