Altered thyroid hormone levels in bacterial sepsis: the role of nutritional adequacy

Depressed triiodothyronine and elevated reverse triiodothyronine levels are commonly seen in patients with acute and chronic illness and in patients receiving markedly hypocaloric diets. To investigate the role of nutritional adequacy in causing the altered thyroid hormone levels found in severe illness, we studied patients with bacterial sepsis who were receiving a variety of nutritional regimens. Thirteen patients received only 5% dextrose in water (600-1000 kcal/day), 7 of whom were in shock. Seven patients received total parenteral nutrition (2500-3500 kcal/day). Analysis of thyroid hormone levels in these groups and in controls shows that a large component of the alteration in thyroid hormone levels found in patients with severe illness is due to the caloric deprivation associated with such severe illness.