Helder Quirino Fernandes MD, Presenter: Nothing to Disclose

Selma Souto, Abstract Co-Author: Nothing to Disclose

Patricia Oliveira, Abstract Co-Author: Nothing to Disclose

José Pedro Henriques Patrício MD, Abstract Co-Author: Nothing to Disclose

Ana Cristina Oliveira, Abstract Co-Author: Nothing to Disclose

Jorge Pereira MD, Abstract Co-Author: Nothing to Disclose

Daniel Braga, Abstract Co-Author: Nothing to Disclose

Jose Medina, Abstract Co-Author: Nothing to Disclose

00030490-DMT et al, Abstract Co-Author: Nothing to Disclose

Amiodarone induced thyrotoxicosis (AIT) can be caused by an excessive hormone synthesis and release (AIT type I; in patients with underlying thyroid disease), by a destructive process (AIT type II), or can be of a mixed type. The management of type I AIT centers on anti-thyroid drugs, while type II responds better to steroid therapy. The mixed type can be treated with both. Generally, all patients get medicated with both drugs. The identification of the type of AIT would allow for a more rational and appropriate management strategy. Recently, Piga M. et al, 2008, have shown the usefulness of 99mTc-sestamibi thyroid scintigraphy (STS) in the differential diagnosis of AIT. They consistently found AIT type I to be characterized by a diffuse and persistent uptake of sestamibi (without significant washout), while AIT type II was characterized by the absence of significant uptake. When a faint persistent sestamibi uptake with no significant washout or a considerable uptake with a quick washout were found, the AIT was reported as being of an indeterminate type. The aim of this paper is to report the authors' experience with STS and AIT.  

The authors present three patients with AIT, all examined in the Endocrinology Department and referred for colour-flow Doppler sonography (CFDS) and STS.

Patient 1: STS showed no significant uptake, consistent with AIT type II. Patient 2 and 3: STS revealed initial thyroid uptake with significant washout, consistent with indeterminate type of AIT. All patients had normal blood flow on CFDS.  

In all three patients, STS was decisive to the determination of the AIT type and, consequently, to their therapeutic management.

Larger series' data confirming STS as an accurate diagnostic tool in AIT would allow for its incorporation in the routine evaluation of all such patients, and the avoidance of relevant side effects

Fernandes, H, Souto, S, Oliveira, P, Patrício, J, Oliveira, A, Pereira, J, Braga, D, Medina, J, et al, 0, Can 99mTc-sestamibi Thyroid Scintigraphy Make the Difference in the Differential Diagnosis of Amiodarone-induced Thyrotoxicosis?.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8009629.html