Endocrine and Metabolic Disorders in the ICU

The knowledge of metabolic disorders in critically ill patients has grown in the last decade. Metabolic alterations have been studied for more than a century and are composed of a big number of diseases and conditions. The word metabolism comes from the Greek word μεταβάλλω (meta-ballo), meaning to “change,” and refers to the complex number of chemical processes that happen in a living organism and that allow to change the molecules and use them to support the living process. The endocrine system represents a connection of the organs and allows complex changes in the systemic metabolism to adapt the organism to different conditions. Intensive care unit (ICU) admission is per se a stressful situation that can therefore be a trigger for deep metabolic and endocrine changes. Patients admitted to the ICUs have important physiological derangements that can be caused by the disease that brought the patient to the ICU, e.g., sepsis or acute kidney injury, or by the therapy associated to ICU admission, like sedation or invasive mechanical ventilation. In this chapter, we will introduce some concept of endocrine and metabolic ICU associated disorders, especially regarding hemoglobin metabolism and glycemic control, and discuss diagnosis and possible therapeutic management.