Thyroid storm in a patient with unknown hyperthyroidism during nonthyroidal surgery-a case report and literature review.

Background: Thyroid storm (TS) is a critical manifestation of hyperthyroidism. In recent years, the risk of perioperative TS is significantly decreased in patients with hyperthyroidism undergoing thyroid surgeries with adequate preoperative preparations. However, those who undergo non-thyroidal operations have higher risk of TS due to easily ignoring the evaluation of thyroid function. The purpose of this case report is to present a patient with TS during nonthyroidal surgery and review similar cases in the literature.

Case presentation: A middle-aged female who received unilateral total knee arthroplasty under general anesthesia developed refractory tachycardia during the operation and was diagnosed with hyperthyroidism via laboratory tests after surgery. She was suggestive of TS based on the Burch and Wartofsky scoring system and relieved after etiological treatments. She was discharged 10 days after surgery and continued to take antithyroid medication.

Conclusion: We recommend that a comprehensive history collection is warranted. The clinical manifestations of TS during operation could be versatile and atypical. Any abnormalities during an operation like abnormal heart rate, blood pressure, body temperature, or even the unusual anesthetics needed, should not be ignored. In surgeries with general anesthesia, it is necessary to be cautious about TS with an atypical manifestation of tachycardia. Once suspected, supportive and resuscitative treatment along with antithyroid medication should be promptly initiated.