Low T3 syndrome and chronic inflammatory rheumatism

For the clarification of pathogenesis and clinical relevance of decreases of the triiodothyronine (T3) level in patients with chronic inflammatory rheumatism in a group of 63 patients with clinically, paraclinically and roentgenologically diagnosed rheumatoid arthritis (59 times) and with SLE (4 times), respectively, parallel were determined parameters of the thyroid gland function and of the rheumatic activity as well as a subtile drug anamnesis for the medication of antirheumatic drugs was established. In 33 of the 63 patients who were included into the study decreases and low normal values, respectively, for the total T3 (TT3 less than 1.5 nmol/l) were found. In comparison to the remaining 30 patients with normal TT3 a typical constellation of paraclinical parameters of the thyroid gland with distinct reduction of TT3 and free T3 (FT3), low normal total T4 (TT4), slight increase of the reverse T3 (rT3), moderate decrease of the basal and stimulated TSH and an only very small restriction of the binding capacity of the thyroid hormone (TBG) were found. A clinically relevant hypothyroidism is thus to be excluded with certainty. Antirheumatic drugs, in particular steroidal ones (glucocorticoids) may on principle also induce such paraclinical constellations, related to the thyroid gland. In our investigations a therapy with antirheumatic drugs is causally scarcely considered, since both in the group of patients with decrease of T3 and without decrease comparable quantities of antirheumatic drugs including glucocorticoids were administered and the cortisol values in the plasma do not differ. The investigations confirm our already formerly expressed supposition that also in rheumatics a "low-T3-syndrome" is existing as it is otherwise described in consumptive extrathyroidal diseases (NTI).(ABSTRACT TRUNCATED AT 250 WORDS)