9355 Thyroid Storm: In the Aftermath of Thyrotropin Stimulated Scan

Abstract Disclosure: S. Bhandari: None. I. Jamshed: None. A. Bag: None. N. Rastogi: None. A. Ramsetty: None. Introduction: Cases of thyroid storm have been reported in metastatic follicular thyroid cancer following surgery and radioactive iodine treatment [1]. Our patient developed thyroid storm after receiving thyrotropin followed by radioactive iodine scan (RAIU), a phenomenon not described in any formal reports to date. Clinical Case:74-year-old woman with history of metastatic follicular thyroid cancer, presented with altered mental status. CT head was negative. CT C/A/P showed heterogeneous thyroid gland with substernal extension, lucent 2 cm lesion involving T10 vertebrae. She had received 0.9 mg of recombinant human thyrotropin (rhTSH) 2 days before presentation and had thyrotropin-stimulated whole-body scan, and RAIU scan showing enlarged multinodular goiter. RhTSH is used to augment the thyroid radioiodine uptake (RAIU) in the surveillance of thyroid cancer without rendering the patient hypothyroid. TSH was 0.008 ng/ml (n 0.270-4.200 UIU/ml) a month back. Labs now revealed TSH 6.58 UIU/ml (reflecting residual rhTSH activity), total T4 19.8 ng/dl (n 4.9-11.7 ng/dl), free T4 3.0 ng/dl (n 0.7-1.5 ng/dl), total T3 2.52 ng/ml (n 0.35-1.93 ng/ml) and thyroglobulin 2525 ng/ml (n 2.8-40.9 ng/ml) concerning for thyroid storm. Treatment with IV hydrocortisone, methimazole, and beta blockers was initiated which led to normalization of thyroid levels (TSH 3.75 UIU/ml, Total T4 10.6 ng/dl, Free T4 1.4 ng/dl, Total T3 0.47 ng/ml), and clinical improvement.Our patient had a co-occurrence of follicular thyroid cancer with multinodular goiter. Administration of thyrogen could have activated the multinodular goiter leading to precipitation of thyroid storm. Thyroid storm in patients with thyroid cancer following treatment is usually due to destruction of thyroid tissues and activation of metastatic thyroid glands from the primary tumor[2]. Thyroidectomy or radioactive ablation of thyroid is the definitive treatment. Patients should however be bridged to euthyroid state prior to this. Our case highlights a unique presentation in terms of pathophysiology for patients with thyroid cancer in the setting of thyrogen use. Conclusion: Although rare, if patients with known thyroid cancer receive thyrotropin subsequently develop symptoms concerning for thyroid storm, clinicians should evaluate with a thyroid panel for prompt diagnosis and treatment. References: 1.Raef H, Dahhan T, Ahmed M, et alRecurrent thyroid storm induced by heretofore unrecognised causes in a patient with thyroid cancer Case Reports 2009;2009:bcr0720080442. 2.Folkestad L, Brandt F, Brix T, Vogsen M, Bastholt L, Grupe P, Krogh Petersen J, Hegedüs L. Total Thyroidectomy for Thyroid Cancer Followed by Thyroid Storm due to Thyrotropin Receptor Antibody Stimulation of Metastatic Thyroid Tissue. Eur Thyroid J. 2017 Sep;6(5):276-280. doi: 10.1159/000479061. Epub 2017 Aug 3. PMID: 29071241; PMCID: PMC5649237. Presentation: 6/1/2024