Spontaneous bacterial peritonitis: pathogenesis, diagnosis, and management

Spontaneous bacterial peritonitis (SBP) is a common and potentially fatal complication of cirrhosis. Multiple variants of this infection have been described during the past decade; each has a slightly different clinical setting and outcome. The pathogenesis of spontaneous ascitic fluid infection appears to involve translocation of bacteria from the gut to the mesenteric lymph nodes, depressed reticuloendothelial phagocytic activity, and deficient ascitic fluid antibacterial activity. A high index of suspicion of this infection and a low threshold for performing an abdominal paracentesis are required to detect infection early, when survival is most likely. The diagnosis of SBP is based on ascitic fluid analysis, specifically polymorphonuclear cell count and culture (in blood culture bottles). Treatment with a third-generation cephalosporin achieves a cure rate in more than 80% of patients. Despite the improvement in short-term survival during the last decade, the long-term prognosis of cirrhotic patients who survive an episode of SBP remains poor because of the severity of the underlying liver disease and the high rate of recurrence of infection. Selective intestinal decontamination to prevent SBP should be considered in patients at high risk for development of this infection, including hospitalized cirrhotic patients with gastrointestinal hemorrhage or with low ascitic fluid total protein concentration. Because SBP is a marker for poor prognosis in patients with cirrhosis, survivors of an episode of this infection should also be considered for liver transplantation.