euthyroid sick syndrome

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eu·thy·roid sick syn·drome

abnormalities in levels of hormones and function tests related to the thyroid gland occurring in patients with severe systemic disease. Thyroid function is actually normal in these patients, and it is uncertain whether treatment of these abnormalities would be beneficial.

euthyroid sick syndrome

Lab medicine A “condition” in Pts who are critically ill with nonthyroid diseases that alter serum levels of thyroid hormones which, in absence of underlying nonthyroid illness, would be correctly interpreted as indicating a disease of the thyroid 'axis' Lab Peripheral ↓/inhibition of 5'-deiodinase, the deiodination enzyme, resulting in ↓ peripheral 5'-monodeiodination of thyroxine–T4, reversed, free, and total T3; TSH, TRH, and usually free thyroxine levels are normal. See Hyperthyroidism, Hypothyroidism.

euthyroid sick syndrome

Any derangement in thyroid hormone blood levels in patients affected by another (usually critical) illness. The altered levels of thyroid hormones are not caused by primary thyroid dysfunction; they return to normal when the underlying illness is successfully treated.


having a normally functioning thyroid gland.

euthyroid sick syndrome
a euthyroid state in which extrathyroidal factors cause a reduction of serum T3 or T4 and elevation of reverse T3 levels. Seen in patients with systemic illness, trauma, fever, starvation, treatment with glucocorticoids, etc. May be a protective metabolic effect.
References in periodicals archive ?
added that there is no role for T3 in the treatment of the euthyroid sick syndrome, either.
36-38) The administration of TNF-[alpha] and IL-1 to humans or experimental animals has resulted in thyroid hormone abnormalities that resemble the euthyroid sick syndrome.
In patients with euthyroid sick syndrome, serum free-[T.
Serum TSH levels in patients with euthyroid sick syndrome may be normal, mildly reduced, or frankly suppressed.
4, 38, 54) Administration of TNF-[alpha], IL-1 and IL-6 to humans or experimental animals has caused changes in thyroid function that resemble euthyroid sick syndrome.
60) These results suggest that NF-[kappa]B activation by TNF-[alpha] may represent an important molecular factor in the pathogenesis of euthyroid sick syndrome, where the underlying disorder is associated with the increased level of TNF-[alpha].
4] levels in a patient with a low-normal TSH level, is the hallmark of euthyroid sick syndrome.
Differentiation between secondary hypothyroidism (pituitary or hypothalamic) and euthyroid sick syndrome may be difficult.
In such patients, a careful assessment of multiple tests may be needed to distinguish patients with euthyroid sick syndrome.
With recovery from underlying illness, the spectrum of thyroid abnormalities observed in patients with euthyroid sick syndrome rapidly disappears.
Chow CC, Mak TW, Chan CH, et al: Euthyroid sick syndrome in pulmonary tuberculosis before and after treatment.