Endocrine and Metabolic Changes in Severe Inflammatory Illness

Over the past few decades, the inextricable link between the endocrine, immune and nervous systems formed the basis of a new field, dubbed psychoneuroimmunology. In this paradigm, one system is subject to the vicissitudes of the other through several intricate feedback loops, such that conditions affecting the one have farreaching effects on the other. As such, critical illness (especially sepsis and septic shock) is mostly accompanied by inflammation a state that best exemplifies the abovementioned relationship between the three systems. During this state, cytokines and other inflammatory mediators such as IL-1β, IL-6 and TNF alpha exert their effects both locally, at the level of various endocrine glands, and centrally, by affecting hypothalamic and pituitary function. In turn, the hypothalmic-pituitary axis represents the epitome of systems integration by acting as a neuro-endocrine control unit, in essence, directing the physiology of survival in an abnormal internal environment.