From the Research
Sick euthyroid syndrome, also called nonthyroidal illness syndrome, is a condition where patients with normal thyroid function develop abnormal thyroid hormone levels during severe illness, characterized by low T3 levels, normal or low TSH, and sometimes low T4 in severe cases, and does not require specific treatment for the thyroid abnormalities as it typically resolves once the underlying illness improves. This condition is commonly seen in critically ill patients with conditions like sepsis, major trauma, heart failure, or after surgery, as noted in a study published in Cureus in 2024 1. The body deliberately alters thyroid hormone metabolism as an adaptive response to conserve energy during illness. Some key features of sick euthyroid syndrome include:
- Low serum levels of triiodothyronine (T3)
- Normal or low levels of thyroxine (T4)
- Normal or low thyroid-stimulating hormone (TSH) levels
- Absence of intrinsic thyroid disease
- Association with severe illness, such as heart failure, chronic kidney disease, and severe sepsis Treating these patients with thyroid hormone replacement is not recommended and may be harmful, as stated in a study published in Comprehensive Physiology in 2016 2. Healthcare providers should focus on addressing the primary illness rather than correcting the thyroid lab values, as emphasized in a study published in Cureus in 2024 3. Distinguishing sick euthyroid syndrome from true thyroid disorders is important to avoid unnecessary thyroid treatment in critically ill patients, as highlighted in a study published in the Journal of the Association of Physicians of India in 2022 4. Overall, recognizing and understanding sick euthyroid syndrome is crucial for providing appropriate care to critically ill patients and avoiding unnecessary treatment, as concluded in a study published in Cureus in 2024 1.