Endocrine Abstracts

We present a case of relapsing Graves thyrotoxicosis in a 58yr old lady who initially presented in 2005 with a large multinodular goitre with retrosternal extension. She had evidence of mild thyroid eye disease (TED) at the time. A total thyroidectomy was performed in 2014 due to recurrent relapses of thyrotoxicosis and poor compliance with carbimazole. Two years following thyroidectomy she developed thyrotoxicosis. Her thyroxine was stopped. A Technetium uptake scan showed a mediastinal thyroid remnant. She developed worsening TED with elevated TRAB at 26.4U/l. She was commenced on carbimazole again and referred to ophthalmology. Her TED stabilised and due to persistent thyrotoxicosis and at times non-compliance with carbimazole, decision was made to treat her thyroid remnant with radioactive iodine. She was given 524 MBq of radioiodine (I-131) in April 2024. Due to her previous TED this was covered with a one-week course of Prednisolone. One week following RAI treatment she presented to ED with chest pain. This was thought to be due to thyroiditis post RAI in her remnant, as all other cardiac investigation were negative. Her repeat TFT’s showed a normal free T4 of 18 pmol/l, mildly elevated free T3 of 7 pmol/l and a suppressed TSH. She stopped carbimazole post RAI despite advice to continue. In August 2024 she presented again with weight loss and palpitations, free T4 29.8 pmol/l, free T3 9.1 pmol/l and a suppressed TSH. Carbimazole 15 mg was recommenced. This case illustrated challenges in the treatment of Graves in a mediastinal remnant. We are currently considering if she would benefit from a second dose of RAI.