Endocrine Disease and Dysfunction Chapter 162 ■ Endocrinopathy in the Icu

During critical illness, the stressors are multiple and include emotional and physical stress such as trauma or infection, and various therapeutic or diagnostic interventions such as surgery, arterial or venous catheterization, laryngeal intubation and mechanical ventilation, and drugs. It is also paramount to recognize that stress is sustained at a certain level of intensity for several days with additive and unpredictable surges. Thus, the host has to adapt to counteract prolonged stress while maintaining ability to adjust to unpredictable surges of stress. The integrity and flexibility of host response to these stressors is essential to survive critical illness. The development of molecular biology has provided scientists with tools to demonstrate the close interaction between the neuroendocrine and immune system. It is now recognized that the “stress system” has two main components: the corticotropin-releasing hormone/vasopressin neurons of the hypothalamus and the locus ceruleus noradrenaline/autonomic neurons of the brainstem (1). In this chapter, we will summarize recent knowledge on how immune molecules such as interleukin or nitric oxide signal the brain to generate both neurologic and hormonal responses aimed at downgrading the immune system when the inflammatory response is no longer needed. Abbreviations used in this chapter are presented in Table 162.1.