Early postoperative levothyroxine initiation after total thyroidectomy for Graves' disease.

Serum FT3 levels in hyperthyroid Graves' disease patients decreased significantly immediately after total thyroidectomy and fell within the normal range by postoperative day 1.

• 18 patients with hyperthyroid Graves' disease were included in this subgroup analysis.
• Blood samples were collected at multiple time points: day before surgery (D-1), 15 minutes after surgery (D0), postoperative days 1 and 3 (D1, D3), 3 weeks (W3), and 3 months (M3).
• FT3 levels were significantly decreased immediately after surgery (D0) and were within the normal range by D1.
• Despite LT4 initiation on D1, FT3 levels continued to decline by D3 and remained low at W3 and M3.

Serum FT4 levels in hyperthyroid Graves' disease patients followed a slower decline than FT3 but remained within the normal range through 3 months postoperatively.

• FT4 decline was slower compared to the rapid postoperative drop observed in FT3.
• FT4 levels remained within the normal range at the 3-month (M3) follow-up time point.
• LT4 replacement was initiated on postoperative day 1 (D1) in all hyperthyroid Graves' disease patients.

In euthyroid Graves' disease patients and thyroid nodule patients, thyroid hormone levels remained within or around the reference range throughout the observation period.

• 12 patients with euthyroid Graves' disease and 12 patients with thyroid nodules were included as comparison groups.
• Hormone levels in these groups stayed within or around the reference range across all time points from D-1 through M3.
• This contrasted with the significant perioperative hormonal fluctuations observed in the hyperthyroid Graves' disease group.

No evidence-based standards currently exist regarding the timing of levothyroxine replacement therapy initiation in hyperthyroid Graves' disease patients undergoing total thyroidectomy.

• LT4 replacement from the first postoperative day had been the standard of care at the authors' institution but had not been thoroughly examined for clinical validity.
• The study was designed to investigate perioperative thyroid hormone kinetics to assess the safety and efficacy of early LT4 initiation.
• The authors note these results could inform future guidelines supporting earlier postoperative LT4 initiation.

The study included a total of 42 patients who underwent total thyroidectomy across three disease groups.

• 30 patients had Graves' disease (18 hyperthyroid and 12 euthyroid) and 12 had thyroid nodules.
• Blood samples were collected at five standardized time points: D-1, D0 (15 min post-surgery), D1, D3, W3, and M3.
• The study design allowed direct comparison of perioperative thyroid hormone kinetics across disease states.