Apathetic Thyrotoxicosis Secondary to Atypical Subacute Thyroiditis

ObjectiveTo report a case of apathetic thyrotoxicosis with an etiology of subacute thyroiditis.MethodsWe describe the patient’s clinical findings, laboratory findings, and clinical course.ResultsAn 85-year-old woman with no history of thyroid disease presented with severe obtundation and altered mental status. Laboratory testing documented elevated free thyroxine and free triiodothyronine concentrations and a suppressed thyrotropin concentration. Thyroid antibodies were absent. A radioactive iodine study revealed severely diminished uptake, suggestive of thyroiditis. After a short course of steroids, the patient’s mental status returned to baseline. Follow-up laboratory testing showed normalizing thyroid function.ConclusionEven in the absence of a history of thyroid disease, we recommend considering thyroid dysfunction in the differential diagnosis of patients who present with altered mental status, particularly in the elderly population. (Endocr Pract. 2012;18:e127-e129)