Systemic inflammation and sepsis. Part I: Storm formation

Sepsis is still a major cause of morbidity and mortality. It results from a dysregulated immune response to infection that leads to organ and system dysfunction. The inflammatory response to pathogenic microorganisms implies a dynamic, complex chain of events leading to endothelial and immune system activation. The purpose of this process is to control infection and repair tissues. However, both host and microorganism factors may result in severe forms of systemic inflammation with a high mortality rate. Sepsis falls within this complex scenario, where the inflammatory storm and the causative microorganism converge in a severe multisystem presentation. This manuscript is divided into two parts. Part I describes the mechanisms triggering systemic inflammation and progression to sepsis, together with its main biological markers. Part II analyzes the mechanisms leading to organ dysfunction.