Serum triiodothyronine concentration in thyroid storm.

Serum triiodothyronine levels were elevated in 6 patients with thyroid storm (769 plus or minus 181 ng/100 ml) but the values observed were not significantly different from those found in uncomplicated thyrotoxicosis (752 plus or minus 282 ng/100 ml). This observation suggests that the pathogenesis of thyroid storm resides in mechanisms other than a simple increase in serum triiodothyronine concentration.