Septic shock: Metabolic effects
Advanced, Clinical Subspecialties
Septic shock is a hypermetabolic state in which the body responds to the infection with an amplified immune response, which results in fevers and increased protein production. Due to the associated vasodilation, along with increased energy requirements, the body also responds with tachycardia and tachypnea to keep up with metabolic demands. Unfortunately, during this state of increased metabolic demands, due to the nature of this illness, it is difficult to get normal baseline nutrition, let alone the increased energy stores that the body needs to keep up with the hypermetabolic state. Due to increased cellular metabolism, there is also increased metabolic by-products, which are sometimes toxic and are thought to be a potential precursor to the multi-organ failure that is commonly seen in septic shock.
One of the metabolic by-products that has received a lot of interest in septic shock is hydrogen peroxide. Hydrogen peroxide is a free radical that causes cellular oxidative damage through the destruction of DNA, proteins, and lipids. Another common by-product in the setting of sepsis is lactic acid. In septic shock, the body cannot keep up with oxidative metabolism and will commonly revert to anabolic metabolism in cells that do not receive enough oxygen supply. The production of lactic acid can further disrupt homeostasis and have significant impact on bodily functions.