Endocrine Abstracts

We present the case history of a 73-year-old woman who presented to ophthalmology reporting ‘eyelids opening too much’ with orbital grittiness, watering and a staring gaze for 9 months. The patient had unequal palpebral apertures with bilateral upper lid retraction, worse on the left. Her clinical activity score was 4/7 with gaze evoked orbital pain, active swelling of the lids, conjunctival redness and caruncle inflammation. Visual acuity was normal (6/6 right eye, 6/12 left eye) and no evidence of impaired colour vision on Ishihara testing. The left eye was proptosed (21mm) with firm retropulsion. The patient had been diagnosed in 2010 with follicular thyroid carcinoma (FTC) with pelvic, spine and rib metastatic disease. Her treatment for thyroid cancer comprised of total thyroidectomy in 2010 and three doses of radioactive-iodine (RAI) between 2010 and 2012 (total dose 17GBq). Thyroid metastases remained stable between 2010 and 2018 until there was progression at the iliac crest which was treated with external beam radiotherapy in 2018 and 2020. She had further RAI in 2019, 2022 and 2023 (total dose 16.5GBq). In 2023 an increased rate of progression was noted and following failed lenvatinib treatment, the decision was made for best supportive care. At joint endocrine/ophthalmology review, previous investigations were noted showing suppressed TSH with normal FT4 and FT3 levels until 2023 when FT3 levels became raised, despite taking only levothyroxine 100 mg daily. TRAb levels were elevated at 39.4 IU/l. We concluded that the patient developed Graves’ orbitopathy following total cumulative RAI dose of 33.5GBq with elevated TRAb levels contributing to progression of malignancy with mild T3 toxicosis originating from metastatic FTC. This is a rare case highlighting the importance of measuring TRAb levels in cases of thyroid cancer if disease progression suddenly increases particularly for patients treated with multiple doses of RAI.