Chapter 76 - Endocrinology of the Stress Response During Critical Illness

Abstract

The stress system receives and integrates diverse cognitive, emotional, neurosensory, and peripheral somatic signals that arrive through distinct pathways. Activation of the stress system leads to behavioral and physical changes that are remarkably consistent in their qualitative presentation. This observation was noted first by Hans Selye, who in 1936 reported that biologic, physical, or psychologic stressors generally precipitate a similar response, which he named the “general adaption syndrome,” or stress response. The acute stress response is mediated primarily by the hypothalamic-pituitary-adrenal axis as well as the sympathoadrenal system and results in increased circulating levels of cortisol, epinephrine, and norepinephrine. The stress response is normally adaptive and time limited and improves the chances of the individual for survival. Critically ill and injured patients, however, have a prolonged stress response, which may last for weeks. It previously was assumed that the stress response of critical illness was an extension of the acute stress response. However, recent data suggest that the chronic stress response differs qualitatively and quantitatively from the acute stress response. This chapter reviews the stress response characteristic of critically ill patients.