Perioperative endocrine dynamics in euthyroid versus hyperthyroid patients with Graves’ disease undergoing total thyroidectomy: a prospective cohort study

BACKGROUND: Total thyroidectomy is a definitive treatment for Graves’ disease, but perioperative endocrine dynamics may differ depending on preoperative thyroid function. Recent advances in anesthetic and surgical techniques have substantially reduced perioperative stress during thyroidectomy, even in patients with active thyrotoxicosis. Clarifying these differences is clinically important, as surgery is often required even when full biochemical control cannot be achieved. This prospective study compared perioperative endocrine dynamics between euthyroid and hyperthyroid Graves’ disease patients undergoing total thyroidectomy. METHODS: Thirty-nine patients with Graves’ disease were prospectively enrolled and classified into hyperthyroid (HT, n = 17) or euthyroid (ET, n = 22) groups based on preoperative hormone levels. Blood samples were obtained at three time points: the day before surgery (T0), after thyroid removal (T1), and the morning after surgery (T2). Free triiodothyronine (FT3), free thyroxine (FT4), cortisol, and thyroglobulin (Tg) levels were measured. RESULTS: FT3 significantly decreased at T1 in both groups (HT: 8.21 ± 4.51 → 6.19 ± 3.65 pg/mL, p < 0.0001; ET: 2.78 ± 0.47 → 2.44 ± 0.48 pg/mL, p < 0.001). FT4 remained stable in the HT group but slightly increased in the ET group. Cortisol levels at T1 were significantly lower in the HT group compared with the ET group (1.95 ± 1.15 vs. 3.61 ± 1.69 µg/dL, p < 0.005), with no difference at T2. Postoperative Tg elevation correlated with thyroid weight. No significant differences were observed in operative time, complications, intraoperative physiological stress markers (including body temperature, blood pressure, and heart rate), or anesthetic drug requirements between the two groups. CONCLUSION: Perioperative endocrine patterns showed no signs of exaggerated physiological stress in hyperthyroid patients. These results imply that total thyroidectomy may be feasible under contemporary perioperative management without significant endocrine or stress responses. However, these results should be interpreted with caution.