Thyroid Dysfunction Relation to Morbidity and Mortality in Critically ill Patients

Abstract

Patients admitted to the intensive care unit (ICU) typically present with altered levels of circulating hormones. One of these changes is the level of thyroid hormones which may affect 60 to 70% of critically ill patients these changes may affect patients with no previous intrinsic thyroid disease. The nonthyroidal illness syndrome, also known as the low T3 syndrome or euthyroid sick syndrome, describes a condition characterized by abnormal thyroid function tests encountered in patients with acute or chronic systemic illnesses. The laboratory parameters of this syndrome include low serum levels of triiodothyronine (T3) and high levels of reverse T3, with normal or low levels of thyroxine (T4) and normal or low levels of thyroid-stimulating hormone (TSH). The sick euthyroid syndrome should not be viewed as an isolated abnormal event but as part of a generalized systemic endocrine response to illness. This syndrome results from alterations in the peripheral metabolism of the thyroid hormone