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

Area of Science:

• Endocrinology
• Surgical Science

Background:

• Thyrotoxicosis management often involves surgical intervention.
• Understanding the perioperative hormonal changes is crucial for patient care.

Purpose of the Study:

• To investigate the dynamic changes in serum thyroid hormones and thyroglobulin (Tg) following subtotal thyroid resection for thyrotoxicosis.
• To assess the clinical relevance of Tg release during surgery on thyroid hormone concentrations.

Main Methods:

• Serum samples were collected from 10 patients undergoing subtotal thyroidectomy.
• Measurements included total thyroxine (TT4), free thyroxine index (FT4I), total triiodothyronine (TT3), reverse T3 (rT3), thyroglobulin (Tg), and thyroid-stimulating hormone (TSH).
• Samples were analyzed pre-operatively, during operation, and for 18 days post-operatively.

Main Results:

• Serum Tg levels dramatically increased during surgery, peaking at approximately 26 nmol/l, then declining below pre-operative levels by day 18.
• Postoperative TT4 and FT4I decreased by over 50% compared to pre-operative values.
• Serum TT3 decreased during surgery, while rT3 initially increased and then decreased post-operatively.
• TSH levels remained low initially but began a steady rise around day 10.

Conclusions:

• Subtotal thyroid resection for thyrotoxicosis leads to a significant perioperative release of Tg.
• The substantial release of Tg during surgery does not appear to clinically influence serum T4 concentrations.
• Hormonal profiles show distinct patterns for TT4, FT4I, TT3, rT3, and TSH in the immediate and short-term post-operative periods.