Endocrine Abstracts

Introduction: Thyrotoxicosis is a clinical state of inappropriately high levels of circulating thyroid hormones (TH), most commonly caused by Graves’ disease (GD). First line treatment includes antithyroid drugs (ATD). Complications such as agranulocytosis could limit their use, leaving radioactive iodine treatment (RIT) as a treatment of choice.

Case presentation: A 67-year-old woman was admitted for severe thyrotoxicosis (TSH <0.01 mIU/l, FT4 52.2 pmol/l, FT3 11.2 pmol/l, anti-TSH receptor antibodies, TRAb 12.6 IU/l, ref. range <1.75). Her past medical history was remarkable for GD. She was previously initially treated with methimazole, replaced later with propylthiouracil (PTU) due to the development of urticaria. On admission she was given 300 mg of PTU with high doses of propranolol. On the second day of hospitalization, agranulocytosis was developed, which lead to cessation of PTU and initiation of supportive and symptomatic treatment. Propranolol at a dose of 160 mg/day and oral prednisone increasing the dose up to 80 mg/day were administrated, but unfortunately with no response. Thus, considering the high free fractions of TH (FT4 57.5 pmol/l, FT3 23.3 pmol/l) and TRAb 15.7 IU/l, it was decided to perform therapeutic plasma exchange (TPE), in order to prevent complications and improve the thyroid hormonal status before referring to RIT. Two TPEs were performed in 3 days. Significant improvement was noted in the thyroid hormonal status (FT4 31.4 pmol/l, FT3 7.1 pmol/l, TRAb 4.93 IU/l) and patient’s general condition. RIT was subsequently applied, and after month and a half normalization of FT4 17.0 pmol/l and FT3 3.6 pmol/l was achieved with lower TRAb 2.30 IU/l.

Conclusion: TPE is not currently recommended for the treatment of hyperthyroidism, but in severe cases where ATD are contraindicated or ineffective, TPE may be initiated as bridge therapy to RIT or thyroidectomy.