Endocrine Abstracts

Introduction: The differential diagnosis between Graves’ disease (GD) and gestational transient thyrotoxicosis (GTT) is difficult in the absence of history and clinical features of GD. In this study, we aimed to determine the role of peak systolic (PSV) and end-diastolic velocities (EDV) of the right and left inferior thyroid arteries (ITA) as measured by color-flow Doppler ultrasonography (CFDUSG) for discriminating GTT from treatment naive GD.

Methods: ITA-PSV and EDV of 41 patients with GTT, 31 age matched pregnant patients with GD, 24 age and sex-matched non-pregnant patients with GD and 25 age and sex-matched healthy euthyroid subjects were assessed by CFDUSG. Patients were diagnosed based on the history, clinical findings and TSH-receptor antibody (TRAb) levels.

Results: The mean ITA-PSV and EDV in patients with GTT were significantly lower compared to pregnant patients with GD and higher compared to healthy euthyroid subjects. However, the mean ITA-PSV and EDV in pregnant patients with GD were significantly lower compared to non-pregnant patients with GD (Table 1). ITA-PSV and EDV were positively correlated with TRAb levels (r=0.515 for right ITA-PSV, r=0.463 for left ITA-PSV, r=0.615 for right ITA-EDV and r=0.526 for left ITA-EDV respectively). However, in spite of the significant difference between mean ITA-blood flow velocities, an overlap was found between ITA blood-flow velocities in a considerable number of patients with GTT and pregnant patients with GD.

Conclusion: Due to the overlap occuring between a substantial number of patients, the measurement of ITA-blood flow velocities by CFDUSG is not a useful diagnostic tool for differential diagnosis between GTT and GD during pregnancy.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.