Plasmapheresis rapidly eliminates thyroid hormones from the circulation, but does not affect the speed of TSH recovery following prolonged suppression

Objective: To report an attempt to shorten the preparation interval before radioactive iodine administration using plasmapheresis in a 77-year-old woman with a history of papillary thyroid carcinoma with local recurrence and lung metastases, in whom the administration of a high dose of radioactive iodine was intended as a desperate rescue procedure. Methods: The patient was initially started on cholestyramine. Two days later, plasmapheresis was performed. Results: Plasmapheresis rapidly decreased free tri-iodothyronine (FT ₃) and free thyroxine (FT₄). Serum FT₄ subsequently remained low, while FT₃ recovered the next day. Thyroid-stimulating hormone (TSH) reached 25 mlU/l in 14 days, which is within the time frame required to reach the target TSH level by withdrawing levothyroxine alone. Conclusion: Plasmapheresis is very effective in eliminating thyroid hormones from the circulation. However, it does not seem to accelerate thyrotroph recovery to a considerable extent after prolonged suppression.