Lacking evidence for release of thyroid hormones from circulating thyroglobulin during subtotal thyroidectomy

Abstract

The effect of subtotal thyroid resection for thyrotoxicosis on concentrations of serum thyroid hormones and thyroglobulin (Tg), was determined in 10 patients during operation and the subsequent 18 days. Mean serum Tg responded drastically, increasing from a pre-operative value of 0.30 nmol/l to a peak value of approximately 26 nmol/l during operation followed by a gradual decline to levels lower than before surgery on day 18. Mean serum total thyroxine was 114 nmol/l pre-operatively and free thyroxine index (FT4I) 105 units. Both fluctuated only slightly during operation. Postsurgically, the mean values decreased to below 50% of the pre-operative level. Mean serum total triiodothyronine (TT3) was 1.46 nmol/l pre-operatively. It decreased during operation, reaching a nadir of 0.55 nmol/l on day 2, whereafter the concentration increased slightly. Mean serum reverse T3 (rT3) was 0.45 nmol/l pre-operatively, increased 62% during surgery, and decreased postsurgically. The mean value of serum thyroid stimulating hormone (TSH) was 0.61 mU/l pre-operatively and remained below 1 mU/l during and after operation, but from day 10 concentration began to rise steadily. It is concluded that the vast release of Tg during thyroid resection did not contribute to the concentration of serum T4 to an extent of clinical relevance.

Early change of thyroid hormone concentration after 131I treatment in patients with solitary toxic adenoma

“…Our finding, that Tg concentration is still increasing while thyroid hormone levels are already decreasing, shows that a release of thyroid hormones from circulating Tg in serum is not clinically relevant. This suggestion supports the results of Date et al (8) who observed ten patients after subtotal thyroidectomy. They found significant increase in Tg concentration but unchanged total T 4 and decreased total T 3 in serum.…”

Total thyroidectomy in Basedow-Graves� disease treatment: our experience

“…However, in 1988 Blichert-Toft paved the way for a new vision demonstrating an improvement of the exophthalmos in all patients after total thyroidectomy (28). Similar observations were later reported by Razack in 1997 and by Borrelli in 2000 (29,30).…”

Hyperthyroidism after surgery for primary hyperparathyroidism

“…Indeed, the previously held assumption that a peri-operative Thgl increase denotes thyroid injury with leakage of thyroid hormones may be incorrect. An increased Thgl level with normal T4 and T3 concentrations can be seen in thyroiditis and in thyroid cancer and, according to recent studies on patients operated on due to Grave's disease, a marked peri-operative rise in Thgl concentration was reported without an increase in thyroid hormones [30,31,32]. Third, pHPT patients with postoperative hyperthyroidism showed an early peri-operative rise in T3 concentration followed by an increase in T4 and rT3, which is not a reaction of thyroid hormone leakage due to thyroiditis in which a more dominant release of T4 is seen [33].…”