LOW TRIIODOTHYRONINE SYNDROME IN NON THYROIDAL DISEASES - DISTRIBUTION AND SERUM TSH CONCENTRATION STUDIES

  • 1 January 1978
    • journal article
    • research article
    • Vol. 39  (4) , 303-312
Abstract
Thyroid explorations were made in 57 patients complaining of serious illnesses to identify low T3 [triiodothyronine] syndrome. All these patients were clinically euthyroid as assessed by normal values of T4 [thyroxine] concentration, RT3U [resin T3 uptake] ratio and F[free]T4I. All the patients included in this study had significantly low serum T3 (42 .+-. 29 ng/100 ml) and FT3I (0.44 .+-. 0.30). Low T3 syndrome was particularly frequently seen in patients with cancer (8/10), hepatic cirrhosis (5/6), renal failure (6/7), old age (5/8) and in serious systemic diseases (6/12). The low T3 syndrome was observed less frequently in anorexia nervosa (4/6) as well as during fasting (1/8). In 31 out of 35 patients with low or normal low T3 concentrations, the serum TSH [thyrotropin] values observed were within the normal limits in 28 cases. The etiologies of isolated decreased T3, mainly the deviation of peripheral conversion of T4 to reverse T3, are discussed. Normal metabolic state and normal TSH concentration encountered in the low T3 syndrome are commented upon equally.