Euthyroid sick syndrome

Under a euthyroid sick syndrome (ESS ), ( synonym: Non- thyroidal illness ( NTI ), Low -T3 syndrome, low T3 syndrome ) refers to changes in thyroid hormone metabolism in clinically euthyroid patients with severe non thyroidal systemic diseases suffer. Including, but not liver cirrhosis, congestive heart failure, myocardial infarction, bypass a part of a coronary heart disease, chronic renal failure, diabetic ketoacidosis, hypothermia, anorexia nervosa, burns or sepsis. Any trauma, surgery, special diets - such as shortages and malnutrition or fasting - can cause within hours changes the homeostatically regulated thyroid function and lead to pathological findings identified as non - thyroidal illness ( NTI ) or euthyroid sick syndrome (ESS ) are referred to. The disorders of euthyroid sick syndrome include changes in the peripheral transport and metabolism of thyroid hormones, in particular with regard to the deiodination in the regulation of TSH secretion, and in some cases of thyroid function itself

The interpretation of these pathological values ​​in euthyroid sick syndrome complicated by various drugs, which firstly reduce the biotransformation of peripheral T4 to T3, such as iodine-containing X-ray contrast agent, propranolol, and amiodarone, and, secondly, drugs such as dopamine, and corticosteroids, the pituitary, the inhibit secretion of TSH, resulting in decreased TSH levels and consequently decreasing thyroidal T4 secretion.

In addition to a decrease in concentration of thyroxine (T4) and triiodothyronine (T3 ) in serum can be observed as a result of deiodination of T4, an increase of metabolically active reverse T3 ( rT3 = Reversing triiodothyronine ). The rT3 increase via a negative feedback loop to further reduce the release of thyroid hormones, as suppressed in the pituitary secretion of thyroid - stimulating hormone ( thyrotropin, TSH) and in the hypothalamus that of Thyreoliberin ( thyrotropin releasing hormone (TRH ) ) will. The reason pro-inflammatory cytokines, glucocorticoids and metabolites are discussed. This euthyroid sick syndrome could represent a protective mechanism to be slowed down by the autoaggressive immunological or metabolic reactions as well as the energy and oxygen consumption of the critically ill organism is reduced. Several occasions but also is hypothesized, that it was in non- thyroidal illness syndrome is a central hypothyroidism, which is in need of treatment. Perhaps the conflicting study results are based on the fact that too heterogeneous collectives were compared.