Sepsis syndrome

A clinical syndrome including fever, leukocytosis, elevated cardiac output, and reduced systemic vascular resistance has been associated with severe i nfection (i.e., sepsis). However, during the last 15 years, many patients h ave demonstrated all of the findings that have traditionally been associate d with "sepsis" but have not had demonstrated sources of infection. This le d to the term "sepsis syndrome" to refer to that population of patients who appeared to have a physiologic and metabolic response associated with, but who did not have, severe infection. More commonly called the systemic infl ammatory response syndrome (SIRS), the sepsis syndrome is now associated wi th the nonspecific systemic activation of the human inflammatory cascade by any of a number of clinical events. The management of the SIRS patient has been ineffective because of incomplete definition of the mechanisms respon sible for the syndrome. It is argued that all of the biological mechanisms that are operative in a simple wound and are beneficial are negative for th e host when activated systemically. Thus, SIRS is seen in three separate sc enarios at present: (1) invasive infection; (2) dissemination of microbes s econdary to failure of host defense mechanisms; and (3) severe activation o f inflammation by injury, shock, severe soft tissue inflammation, and other noninfectious but proinflammatory events. Newer treatment strategies will need to focus not on the inciting event itself but on better control of the complex responses of the host.