SAT472 A Case of Contrast Induced Thyrotoxicosis in a Patient Newly Diagnosed with Hyperthyroidism

Abstract

Abstract Disclosure: E. Askar: None. B. Reddy: None. Background: It is quite uncommon for thyrotoxicosis to manifest itself after the administration of iodinated contrast. Although the actual prevalence has not yet been identified, estimates showed that the prevalence in areas with iodine deficiency is 0.25 to 0.5% and 0.025% in non-iodine-deficient areas with higher risk in elderly patients. Clinical Case: A 68-year-old female presented to the emergency department for 2 weeks of intermittent substernal chest pain associated with diaphoresis. She was diagnosed with hyperthyroidism by an outside clinic approximately one week prior to her presentation and was prescribed methimazole but did not start it. Her physical examination was significant for mild exophthalmos. EKG showed ST depression in anterolateral leads. Laboratory data showed a troponin of 0.328 ng/ml (0.0.015-0.45) which trended up to 4.830 after 3 hours and TSH of <0.005 mIU/L (0.358-3.74), otherwise BMP and CBC were within normal limits. Patient was started on aspirin, statin and heparin infusion along with methimazole. Patient was transferred to tertiary hospital for urgent cardiac catheterization that showed 90 % stenosis of left anterior descending artery (LAD) and 95 % stenosis in distal right coronary artery (RCA). A successful drug eluting stent was deployed in LAD with a plan of staged PCI in RCA. An hour after the procedure, Patient complained of palpitations and diaphoresis. Laboratory findings at that time revealed Free T4 of 17.5 ng/dl (0.9-1.8), Free T3 of 12.3 pg/ml (1.8-4.6) with positive Thyroperoxidase antibody, TSI and TSH Receptor Antibody. Thyroid ultrasound revealed diffusely heterogeneous thyroid gland with increased vascularity, consistent with Graves’ disease. The patient was diagnosed with thyrotoxicosis secondary to contrast administration. She was treated with methimazole 20 mg TID, metoprolol tartrate 25mg BID and hydrocortisone 25 mg BID. Decision was made to postpone the second procedure until trending down of thyroid hormones and improvement of symptoms. A successful staged RCA PCI was performed eight days later and patient did not experience any complications despite exposure to the same dose of iodinated contrast. Conclusion: Rarely, hyperthyroid patients may experience chest discomfort and EKG abnormalities that are consistent with cardiac ischemia. This usually happens in older patients with known underlying coronary artery disease in response to the rise in cardiac contractility and strain caused by thyrotoxicosis. Our case did not have any history or risk factors of coronary artery disease other than hyperthyroidism. This case highlights how recognition of hyperthyroidism may alter management, because the use of some procedures or treatments may acutely exacerbate the condition of the patient. Presentation Date: Saturday, June 17, 2023