Systemic inflammatory response syndrome (SIRS) and sepsis

Abstract

The human body reacts to various insults with a variety of complex reactions. The systemic inflammatory response syndrome (SIRS) refers to a diffuse state of inflammation resulting from many possible etiologies, including, but not limited to: infection, drugs, toxins, adrenal insufficiency, trauma, burns, ischemia, and pancreatitis. Activation of the immune system causes lymphocytes and macrophages to release a variety of cytokines (IL-1, IL-6, IL-8, TNF alpha), enzymes, and vasoactive substances, whose function is to eradicate foreign organisms. Vast amplification of these same mediators may have several unwanted effects including rampant activation of the coagulation cascade, increased metabolism, and capillary permeability. When prolonged, this exaggerated immune system response constitutes the basis of SIRS.While SIRS may result from infectious or noninfectious causes, sepsis by definition is a widespread inflammatory state secondary to a bacterial, fungal, or viral infectious agent. As a continuum of pathological inflammation, sepsis can be understood as SIRS with a proven source of infection.