AN OUTBREAK (159 CASES) OF TRANSIENT THYROTOXICOSIS WITHOUT HYPERTHYROIDISM IN JAPAN

We report an outbreak of transient thyrotoxicosis that occurred bet,we en June and September 1993, in Matsuyama City, Ehime Prefecture. One h undred fifty-nine cases of thyrotoxicosis were identified, all in indi viduals without goiter, Thyroid autoantibodies were absent, and the se rum thyroglobulin level was depressed, Ultrasonography of the thyroid disclosed no abnormal findings, while scintigraphy of the thyroid with Tc-99m revealed poor uptake, About ten days after the onset, the seru m thyroid hormone levels were normalized, No significant elevation of serum viral antibodies was found, These observations suggest that a th yrotoxicosis factitia may have been the cause of the present outbreak.