[Changed thyroid function parameters in severe extrathyroidal diseases].

Patients with critical non-thyroidal illnesses (NTI) often show decreased serum levels of thyroid hormones. We find the so-called low T3-syndrome and the low T3-low T4-syndrome in cases of severe liver- or kidney-diseases, inflammation, metabolic disorders and in emergency situations with danger to life. A strong decrease of the serum-T4-level signals a bad prognosis. In spite of the relative low concentrations of thyroid hormones and a possible disturbance in pituitary regulation, the patients are clinically in an euthyroid situation. There is no hypothyroidism in the common sense, but possibly an adaptation to the morbid situation of the organism with effects on protein- and energy-economy. Therefore the substitution of thyroid hormones is not indicated. In such cases of NTI the diagnosis of real disturbances of thyroidal function is often difficult. The employment of more sensitive TSH-assays may improve this situation.