A 79-year-old female is admitted to the ICU after repair of a pathologic femur fracture with an estimated blood loss of 1.2 L. She is oxygenating well on room air, is hemodynamically stable, and is appropriately alert and oriented. Physical examination is remarkable for incision site tenderness and signs of malnutrition. Laboratory studies reveal normal electrolytes, normal liver function tests, normal TSH and T4, and decreased levels of T3.
What would be the most appropriate management of her deranged thyroid function test?
A. Supportive care with appropriate nutritionCorrect Answer: A
Euthyroid sick syndrome (ESS), also known as nonthyroidal illness syndrome, is often seen in patients with severe critical illness, deprivation of calories, and following major surgeries. Common causes include infection, trauma, cardiopulmonary bypass, and malignancy. Although the exact mechanism is not known, one possible hypothesis is that the presence of thyroid binding hormone inhibitor in serum and body tissues inhibits the binding of thyroid hormone to thyroid-binding protein. Cytokines such as interleukin 1, interleukin 6, tumor necrosis factor alpha, and interferon-beta may affect the hypothalamus and pituitary, thus inhibiting TSH, thyroid-releasing hormone, thyroglobulin, T3, and thyroidbinding globulins production have also been implicated. ESS has been classified as:
Low serum total T3 is the most common abnormality in ESS, and it is seen in about 70% of hospitalized patients. Both low T3 and the T4 syndromes are observed in critically ill patients admitted to intensive care units. Low-serum total T4 correlates with a bad prognosis; the probability of death correlates with the level of serum total T4. When total T4 levels drop below 4 µg/dL, the probability of death is approximately 50%, and when serum T4 levels are below 2 µg/dL, the probability of death reaches 80%.
Thyroid hormone replacement is not needed in patients with ESS (Choices B and C), and there is no role of steroids in the management of ESS (Choice D). Treatment and management of underlying medical illness is sufficient (Choice A).
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