Frequency of Non-Thyroidal Illness Syndrome in Pediatric Patients with Sepsis and Septic Shock

Abstract

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection and "septic shock" the subset of sepsis with circulatory and cellular/metabolic dysfunction associated with a higher risk of mortality. Hemodynamic disturbances occur in sepsis, such as cardiovascular and hormonal balance disorders. Hormonal changes that frequently occur in sepsis are often from the thyroid, in the form of Non-Thyroidal Illness Syndrome (NTIS). NTIS is extensively studied in adults and ICUs but poorly studied in pediatrics and PICUs. NTIS has been described in almost every form of acute or chronic stress and severe illness, infection, trauma, surgery, sepsis and heart disease. As in adults, critical illness in children evokes pronounced changes in the thyroid axis. A low serum concentration of T3 and a rise in rT3 are typically observed in the acute phase of critical illness, possibly reflecting an attempt to reduce energy expenditure. Such peripheral inactivation of thyroid hormone is mainly explained by a decrease in type-1deiodinase activity in liver and kidney, and an increase in type-3 deiodinase activity in liver and muscle.