Acute development of low T3 syndrome and changes in pituitary-adrenocortical function after elective cholecystectomy...

From two groups of female patients (young group: 15 patients aged less than 25 years; elderly group: 15 patients aged more than 65 years) who were subjected to cholecystectomy, blood samples were obtained on the day before surgery, on the day of surgery before premedication and after waking up from anaesthesia and also on days 1, 3 and 7 after surgery. In aliquots of sera the levels of TSH, ACTH, thyroxine (T4), triiodothyronine (T3), reverse triiodothyronine (rT3) and cortisol were estimated with the aid of radio-immunoassay (RIA). The differences between the young and elderly subjects were evaluated with the aid of four different statistical tests. Though no changes in the level of T4 were found, the level of T3 was significantly decreased and that of rT3 was significantly increased on Day 1 after surgery. However, the decrease of T3 was expressed more significantly in the young group and, in addition, an increase of rT3 in the same group was found even before premedication. The level of TSH showed a sharp increase at the end of surgery, which was expressed more in the young group. Though no differences between groups were observed in a sharp peak of the ACTH level during surgery, the increase of cortisol level in the elderly group was significantly higher and remained so during the post-operative period.