A Case of Myxedema Coma Confounded by Dementia and Hypokalemia

Abstract

The hallmarks of myxedema coma are decreased mental status and hypothermia; but hypotension, bradycardia, hyponatremia, hypoglycemia, and hypoventilation may also be present. This case involves a 74-year-old female, with arthritis and dementia, who presented with weakness and failure to thrive. Physical exam was significant for altered level of consciousness, lethargy, pretibial pitting edema and hypotension. Since friends and family were absent, history was obtained per chart review. Initial labs showed severe hypokalemia of 2.0 mmol/L and associated changes of prolonged QT interval and T wave flattening on electrocardiogram (ECG). The family later revealed additional history of thyroidectomy and clarification that the patient had been noncompliant with her medications for at least 6 months. Hypothyroidism was confirmed with a thyroid stimulating hormone (TSH) level of 82.2 U/mL and a free thyroxine (T4) level below normal threshold. Endocrinology was consulted and care was taken when reinstituting her thyroid supplementation after checking cortisol level as well as reviewing her ECGs. This case report illustrates the importance of checking for thyroid dysfunction especially in the elderly who present with altered mental status and unclear history as most symptoms of myxedema coma may be reversible. Furthermore, myxedema coma occurring in the setting of decompensated hypothyroidism is a medical emergency. In this case, despite timely diagnosis and appropriate treatment, her cognitive function failed to improve, and as a result, palliative care was consulted. Ultimately, the family elected for hospice care due to severe dementia, bed-bound status, and failure to thrive.




J Endocrinol Metab. 2019;9(3):71-76
doi: https://doi.org/10.14740/jem574