High concentrations of thyroid-stimulating hormone in untreated glucocorticoid deficiency: Indication of primary hypothyroidism?

Abstract

The authors examined the effect of cortisol deficiency on thyroid function tests before and after glucocorticoid replacement in patients presenting with Addison's disease or isolated adrenocorticotropic hormone deficiency. Seven of 13 cases with cortisol deficiency had raised concentrations of thyroid-stimulating hormone. Of these, two had normal thyroid-stimulating hormone concentrations after glucocorticoid replacement and were euthyroid two years and five months respectively after treatment. One further patient has since been taken off thyroxine and has remained euthyroid. The two patients with Addison's disease presenting with raised thyroid-stimulating hormone concentrations and who are now euthyroid both had positive test results for adrenal and thyroid antibodies. These cases indicate that excess thyroid-stimulating hormone is not necessarily an indicator of long-term thyroid hypofunction in untreated cases of glucocorticoid deficiency. Indeed, thyroid-stimulating hormone concentrations often returned to normal with treatment.