Acute Thyroid Storm Following Thymectomy: A Surprising Result of Undiagnosed Graves' Disease.

Postoperative thyroid storm represents a diagnostic dilemma in patients with overlooked hyperthyroid state undergoing a nonthyroid surgery. We report a 30-year-old female with a history of mixed connective tissue disease who presented with an anterior mediastinal mass and underwent a thoracoscopic resection of the mass. On postoperative day 1, she had an acute change in mental status with fever, tachycardia and hypercapnic respiratory failure requiring intubation and mechanical ventilation. An elevated free thyroxine concentration and almost undetectable serum thyroid stimulating hormone suggested thyroid storm as the culprit. The patient was rendered euthyroid after initiation of therapy with propylthiouracil/methimazole, potassium iodide oral solution and systemic steroid. Histopathology of the resected anterior mediastinal mass showed thymic hyperplasia. In retrospect, the patient had hyperthyroid symptoms before surgery, but this diagnosis was overlooked. Non-thyroid surgeries can trigger thyroid storm in the setting of poorly controlled or overlooked hyperthyroidism. Although uncommon, thyroid storm should be considered in differential diagnosis of perioperative tachycardia and respiratory failure. We emphasize on the importance of preoperative thyroid workup in patients with tachycardia, palpitation, labile blood pressure, unexplained weight changes or poorly controlled anxiety. The significance of a proper preoperative assessment cannot be overestimated.