Triiodothyronine-Induced Thyrotoxicosis in Ophthalmic Graves Disease

The origin of Graves disease remains elusive despite considerable experimental and speculative effort. Throughout the years, a series of ill-defined "stressful" situations have been implicated in its pathogenesis. The increased incidence of thyrotoxicosis during the German occupation of Denmark during World War II,¹ as well as a host of noncontrolled clinical observations, suggest that psychological factors may be important determinants.^2,3 In addition, the "metabolic stress" of rapid weight loss has been reported to precipitate thyrotoxicosis.⁴ Endogenous thyrotoxicosis, developing during or in the wake of thyroid hormone therapy, has been linked causally with this medication.⁵ Exacerbations of active thyrotoxicosis have been reported during triiodothyronine (T₃) suppression testing.^6,7

We report a case of endogenous thyrotoxicosis developing coincident with a T₃ suppression test in a patient with ophthalmic Graves disease who was euthyroid at the onset of testing.

MATERIALS AND METHODS  Determinations of serum total thyroxine