Sick-euthyroid syndrome

Definition

The term sick-euthyroid syndrome may occur in fetal life, acute or chronic illness, exhausting exercise or starvation, which don't result from a thyroid disorder, and which may be present separately or in combination: 1) Primary low-T3 syndrome resulting from hypodeiodination 2) Secondary low-T3 syndrome caused by low-T4 syndrome 3) Thyrotropic adaptation resulting in low-TSH-low-T4 syndrome 4) Impaired plasma protein binding of thyroid hormones 5) Increased concentrations of reverse T3 6) Increased concentrations of 3,5-diiodothyronine (3,5-T2) 7) Measurement artifacts resulting from pathological blood components including free fatty acids, antibodies and drugs.

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