Endocrine Abstracts

Introduction: I present a case of a young patient that had stable thyroid function tests for years on the same dose of thyroid medications and how losing weight on a GLP-1 agonist led to adverse effects.

Case presentation: A 36 year old female initially presented to her GP with thirst, fatigue, urinary frequency and constipation ongoing for weeks. She has a background of hypothyroidism and hypoparathyroidism secondary to thyroidectomy and radiotherapy (2012 for papillary thyroid cancer); ALL (at age 12 which was cured with sibling allogenic transplant); T2DM in remission and depression. At the time of presentation she was on Liothyronine 5 mg , levothyroxine 1500 mg once weekly, Ozempic 0.25 mg once weekly, Adcal-D3 2 tablets , alfacalcidol 1 mg TDS, Ramipril . blood test by GP showed hypercalcemia, acute kidney injury stage 3 and normocytic anaemia and she was sent to hospital for further management. On arrival to hospital, she was managed with IV fluids, nephrotoxic medications and Adcal-D3 were held and she was referred to endocrine team. Thyroid function test was done because she was tachycardic and it showed hyperthyroidism. The plan from endocrine team was stop liothyronine; recheck thyroid function test in a few days; IV fluids; hold Adcal-D3 until calcium levels normalise. Ultrasound thyroid and whole body CT were unremarkable.

Discussion: The conundrum was patient had been relatively stable on her dose of thyroid medications, calcium and vitamin D replacement so it was puzzling she all of a sudden became thyrotoxic and hypercalcaemic. On careful history taking, we realised she had lost 30 kg in less than 2 years since starting Ozempic for her diabetes. The take home message from this case is with the prevalence of weight loss medications it is important for clinicians to be aware of the need to adjust weight based dosing medications to avoid adverse effects.