The Development of Myxedema Coma in the Setting of Euthyroid Sick Syndrome: A Diagnostic Dilemma and Review of Management Strategies

Euthyroid sick syndrome (ESS), also referred to as nonthyroidal illness syndrome, is an intriguing condition characterized by dysregulation of thyroid hormones despite normal thyroid gland function. It is diagnosed by low serum triiodothyronine levels, and, in some cases, other thyroid hormones such as thyroxine and thyroid-stimulating hormone may be affected. This condition arises via various physiologic mechanisms and is associated with intensive care unit (ICU) admissions, caloric deprivation, and severe illness. Myxedema coma (MC) is a rare medical emergency with a high mortality rate. It is caused by severe hypothyroidism, resulting in multiorgan failure with features including adrenal insufficiency, thermal dysregulation, and altered mentation. Generally, it is observed in untreated and poorly managed cases of hypothyroidism. However, stress from infections, surgical procedures, and medical comorbidities may precipitate this condition. It is particularly uncommon to see MC arise in the setting of ESS, especially in a patient with no history of thyroid disease, which makes this diagnosis easy to miss. In our case, a 36-year-old female presented with septic shock and was admitted to the ICU, where she subsequently developed ESS and features of MC. This case report aims to explore the risk factors, features, and diagnostic and therapeutic management of these conditions, as well as the diagnostic challenges that arise when these diseases present simultaneously.