Transient Hyperthyroidism Induced by Thyroid Ultrasound.

OBJECTIVES: Transient hyperthyroidism has been documented following surgical manipulation or direct trauma to the normal thyroid gland. This has best been studied in patients following parathyroidectomy and also reported following trauma to the neck, strangulation, and vigorous palpation of the thyroid gland. It has not previously been reported following a thyroid ultrasound. METHODS: We report the case of a 58-year-old euthyroid woman with a large nontoxic multinodular goiter who developed transient hyperthyroidism following an ultrasound of the thyroid gland. She was not treated with anti-thyroid medications. RESULTS: Two weeks later, her free T3 and free T4 were normal, and 11 weeks after the ultrasound, all thyroid tests, including her TSH, were within the reference range. CONCLUSIONS: We believe this is the first report of a euthyroid individual who developed hyperthyroidism caused by thyroid ultrasonography. We hypothesize that pressure from the ultrasound probe during the examination compressed her large nodules, releasing stored hormone.