Abstract
BACKGROUND: Thyroid storm is a rare, life-threatening disease triggered by an acute event or trauma, such as surgery of the thyroid or another area, and infection. However, recent studies have shown that irregular use or discontinuation of antithyroid drugs is the most common cause of thyroid storm. A cardiovascular event caused by thyroid storm following coronary artery bypass graft (CABG) is high output heart failure with extreme tachycardia, which can be fatal. Thyroid storm after nonthyroidal surgery, especially CABG, has been rarely reported, with only one reported case until now. Herein, we present a case of thyroid storm onset in a patient who underwent CABG. CASE PRESENTATION: A 74-year-old woman with a history of antithyroid medication discontinuation against medical advice underwent urgent CABG. The patient exhibited extreme tachycardia postoperatively, which is highly suggestive of thyroid storm. Although a higher infection risk is an important consideration, a high-dose steroid was used to control the intractable tachycardia that did not respond to beta-blocker administration. Despite appropriate antibiotic treatment, the patient's condition was exacerbated, and she developed multiple organ failure resulting from adult respiratory distress syndrome progression, and she died on day 8 after surgery. CONCLUSIONS: Risk factors for thyroid storm after CABG and its treatment outcomes are rarely reported. Patients with a history of inappropriate antithyroid medication prescription should be in a euthyroid state before surgery. If surgery is imminent, anticipating thyroid storm and its treatment as well as a euthyroid state can improve recovery outcomes postoperatively.