Rapid preoperative blockage of thyroid hormone production / secretion in patients with Graves' disease.

PRINCIPLES

Preoperative management of hyperthyroid patients with Graves' disease who are unable to tolerate thionamides or have poor adherence to therapy is a challenging clinical problem. The goal of our study was to demonstrate the clinical efficacy of a rapid preoperative thyroid hormone blocking protocol and to assess specific surgical and treatment-related complications.

METHODS

Ten patients with thyrotoxicosis due to Graves' disease were treated with a rapid thyroid hormone blocking protocol of Lugol's solution, dexamethasone and a beta-blocker. Two patients continued to receive antithyroid therapy with carbimazole. Adrenal function was assessed 4-6 weeks postoperatively with a low dose (1 µg) adrenocorticotrophic hormone-stimulation test.

RESULTS

Before treatment, all patients had severe hyperthyroidism. Baseline median and interquartile range (IQR) of fT4 was 68.9 (45.7-92.1) pmol/l, and baseline median fT3 and IQR, 30 (19.1-40.9) pmol/l. After 10 days of treatment, the levels of free hormones were significantly reduced with fT4 concentrations slightly elevated (fT4, 26.7 [17-36.4] pmol/l, p <0.001 compared with corresponding pretreatment values), and the fT3 concentration was normal in 8/10 patients (fT3, 6.1 [4.6-7.6] pmol/l, p <0.001 compared with corresponding pretreatment values). All patients were clinically euthyroid with a heart rate of <80/min. Drug tolerability was excellent, and there were no side effects or exacerbation of hyperthyroidism. The peri- and postoperative course was uneventful in all cases. Adrenal function was normal in 7 out of 10 patients 4-6 weeks postoperatively. Three patients showed prolonged secondary adrenal insufficiency with normalisation of adrenal function after 3 to 6 months.

CONCLUSION

Rapid and effective preoperative preparation of patients with Graves' disease is achievable with Lugol's solution, dexamethasone and a beta-blocker. The risk of temporary hypothalamic-pituitary-adrenal axis suppression has to be taken into account.