Tertiary peritonitis

A substantial minority of patients with primary or secondary peritonitis will progress to tertiary peritonitis despite "successful" medical and surgical intervention. Patients at risk are gravely ill, being malnourished, significantly immunosuppressed, and possessing significant physiologic derangement as evidenced by high APACHE II scores. The clinical syndrome is characterized by pyrexia and hyperdynamic/hypermetabolic physiology that progresses to organ dysfunction and ultimately death. Diffuse inflammation of the peritoneal cavity persists in the absence of a well-defined infective focus. Peritoneal cultures are frequently sterile or isolate fungi or bacteria with low intrinsic virulence. Prevention through the use of alternate surgical and antimicrobial approaches is contingent on identifying the patient at high risk. Unfortunately, the benefits of this approach, whether it be broader spectrum antimicrobial coverage or planned relaparotomy, have never been evaluated in randomized prospective studies. Yet, why would a patient, after seemingly appropriate and aggressive intervention progress to tertiary peritonitis? Several factors are involved in the resolution of any infective process: the magnitude of bacterial contamination, the virulence of bacteria and the synergistic effects of multiple species, the presence of adjuvants for growth, competency of the host immune response, and appropriateness of surgical intervention. When the bacterial load and virulence are removed, host defenses are intact, and surgical intervention controls the source of contamination, and effective antimicrobial therapy is selected the risk of recurrent peritonitis is low. However, an imbalance in any one of these may cause the inflammatory/infectious process to fester.