Thyroid Dysfunction Associated with Administration of the Long-Acting Gonadotropin-Releasing Hormone Agonist
A 24-year-old female came to the Department of Obstetrics and Gynecology at Cheil General Hospital & Women's Healthcare Center with right lower abdominal pain 2 months ago and she underwent laparoscopic ovarian cystectomy. Subsequently, she had received subcutaneous injections of leuprorelin acetate of 3.75 mg per month, twice in all. It was accidentally found by another hospital that she had thyroid dysfunction and thyroid enlargement verified by a sonogram 2 days ago. Thus, she was referred to the Department of Internal Medicine.\nHer blood pressure was 111/67 mm Hg, pulse was 80 per minute, and BMI was 18.4 kg/m2 (165 cm/50 kg). Nothing was noteworthy in her medical histoy or family history.\nShe complained of weight loss of 4 kg over 1 year, cold sensation intolerance, and facial flushing. On physical examination, she had diffuse thyroid enlargement and the ECG was normal.\nBoth serum T3 (211.6 ng/dL) and fT4 (38.6 pmol/L) were elevated and TSH (<0.01 µU/mL) was suppressed. Anti-TG Ab (17 U/mL) and anti-TPO Ab (>100 U/mL) were all positive and TBII was 4%. Meanwhile, the reduction of thyroid uptake was discovered on technetium-99m thyroid scan. She was diagnosed with transient thyrotoxicosis and observed without treatment.\nOne month later, TSH (0.01 µU/mL) still had been suppressed, but both T3 (112.3 ng/dL) and fT4 (14.3 pmol/L) were normalized; thereafter, leuprorelin acetate was injected subcutaneously four more times. Two months later, fT4 (9.1 pmol/L) was decreased and TSH (9.81 µU/mL) was elevated without symptoms of hypothyroidism, and observation was continued. Four months later, both fT4 (11.5 pmol/L) and TSH (2.33 µU/mL) were normalized and she is currently under serial assessment ().