Thyroid hormones in generalized scleroderma. A controlled study.

Parameters of thyroid metabolism were analysed in 42 patients with generalized scleroderma and healthy individuals matched with respect to sex and age for comparison. Decreased free thyroxine (p less than 0.01), decreased free triiodothyronine (p less than 0.001), and increased thyroid-stimulating hormone (p less than 0.001) evidenced an associated state of myxoedema in scleroderma. Total thyroxine was normal, and total triiodothyronine was increased (p less than 0.01) probably reflecting binding to abnormal serum proteins in scleroderma. Normal concentrations of reverse triiodothyronine indicated a normal peripheral metabolism of thyroid hormones. Thyroid-stimulating immunoglobulins also analysed were within normal range. Changes in free thyroxine, free triiodothyronine, and thyroid-stimulating hormone were quantitatively small with mean values within normal ranges. In conclusion, this study evidenced a mild associating myxoedema state in generalized scleroderma. Probably, this reflected slight and subclinical affection of the thyroid.