Part of “CHAPTER 36 – ABNORMAL THYROID FUNCTION TEST RESULTS IN EUTHYROID PERSONS“

In critically ill patients, a strong correlation has been found between the serum T₄ level at the time of hospital admission and the mortality rate. Given that the magnitude of depression in thyroid hormones corresponds to the severity of the underlying NTI, the fact that patients who have the greatest thyroid hormone depression have the worst prognosis is not unexpected. A particularly high mortality rate has been noted in critically ill patients with levels of serum T₄ and TSH that remain depressed for >1 week after admission to hospital.5 The serum T₄ depression correlates negatively with survival in a manner that parallels the traditional Acute Physiology and Chronic Health Evaluation II (APACHE-II) prognostic score. Critically ill elderly patients with high serum IL-6 values and low serum albumin levels are more likely to have NTI-related thyroid alterations and have a higher likelihood of dying from their acute illness.71