EUTHYROID SICK SYNDROME

Abstract

Subclinical thyroid dysfunction is a common clinical problem for which there are many controversial issues regarding
screening, evaluation and management. Subclinical hypothyroidism is defined as an elevated serum TSH level associated with
normal total or free T4 and T3 levels. Euthyroid sick syndrome (ESS) identifies abnormalities in thyroid function tests observed
in patients with systemic nonthyroidal illnesses (NTIs) and those undergoing surgery or fasting. Abnormalities of thyroid function
in NTIs have been classified as 1). Low T3 syndrome, 2). Low T3-low T4 syndrome, 3). High T4 syndrome, and 4). Other
abnormalities. The condition is not considered to need treatment because there are no symptoms and the tests go back to normal
when the stressful illness has passed. It has been reported a case of euthyroid sick syndrome of a 49 years old woman, whoÕs
suffering from sistemic illness of space occupaying lession in thoracal VII-VIII (with histopathologycal findings: metastatic
adeno carcinoma). We found low levels of T3 (0.49 nmol/L) and TSH (<0.05 uI/ml), but normal levels of T4 (96.91nmol/L). In
severely ill patients, T4 decreases and both T4 and T3 are inversely correlated with mortality rate.