RT Journal Article SR Electronic T1 Uncommon Causes of Thyrotoxicosis JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 265 OP 278 DO 10.2967/jnumed.107.041202 VO 49 IS 2 A1 Erik S. Mittra A1 Ryan D. Niederkohr A1 Cesar Rodriguez A1 Tarek El-Maghraby A1 I. Ross McDougall YR 2008 UL http://jnm.snmjournals.org/content/49/2/265.abstract AB Apart from the common causes of thyrotoxicosis, such as Graves' disease and functioning nodular goiters, there are more than 20 less common causes of elevated free thyroid hormones that produce the symptoms and signs of thyrotoxicosis. This review describes these rarer conditions and includes 14 illustrative patients. Thyrotropin and free thyroxine should be measured and, when the latter is normal, the free triiodothyronine level should be obtained. Measurement of the uptake of 123I is recommended for most patients.