[Evolution of levels of free thyroxine and thyrotropin in treated Cushing disease].

OBJECTIVE

Determine the frequency and changes in thyroid hormones in Cushing's disease.

METHODS

Free thyroxin and thyrotropin levels were measured in 11 patients (age range 17 to 60 years) with Cushing's disease both before and after resection of the pituitary adenoma.

RESULTS

Free thyroxin levels were low (8.3 to 11.7 pmol/l) in 7 patients. These patients had no clinical manifestations of hypothyroidism. In 4 patients, cure of the pituitary adenoma led to normalization of the thyroid hormones 10 days after operation (13 to 55 pmol/l); in the other cases surgical cure was unsuccessful and thyroxin levels remained low. Cortisol levels were finally normalized in these patients after irradiation of the pituitary, a second pituitary operation, or bilateral resection of the adrenal glands in 2 patients. Normal thyroxin levels were thus achieved. There was no correlation between serum cortisol and free thyroxin.

CONCLUSION

Thyroid hormones should be assayed regularly in patients with Cushing's disease as a supplementary control of treatment effectiveness.