Atypical Thyroid Storm Caused by Metamorphosis of Thyroid Autoimmunity

Objective: To describe a rare case of thyroid storm with atypical presentation resulting from conversion of Hashimoto’s thyroiditis with hypothyroidism to Graves’ disease. Methods: The authors present a case report, including the detailed clinical, laboratory, and radiographic data. They also review other significant reports available in the literature. Results: A 61-year-old woman with a history of long-standing hypothyroidism and more recently of erratic behavior, hallucination, and polysubstance abuse presented to the hospital with altered mental status. In the following 3 days, she developed lethargy, tachycardia, respiratory failure, and severe lactic acidosis. She was afebrile. Clinical features, thyroid function tests, thyroid antibody panel, and thyroid ultrasound were indicative of Graves’ disease developed on a preexisting Hashimoto’s thyroiditis. Clinical conditions rapidly improved after initiation of treatment for thyroid storm. Conclusion: This is the first reported case of thyroid storm resulting from conversion of hypothyroidism due to Hashimoto’s thyroiditis to Graves’ hyperthyroidism. Moreover, the case suggested that an atypical presentation of thyroid storm without fever could be a negative prognostic sign because of the possible association with severe lactic acidosis.