Spontaneous bacterial peritonitis: pathogenesis, diagnosis, and management

Spontaneous bacterial peritonitis (SBP) is a bacterial infection of ascitic fluid which arises in the absence of any other intraabdominal infection source. SBP may develop in all cirrhotic patients with ascites. Gram-negative aerobic bacteria and non-enterococcal Streptococcus spp. are the most common organisms isolated from ascites. Diagnosis necessarily relies on paracentesis and requires a high index of suspicion. The incidence of mortality of the first episode varies between 10% and 46%. Early antibiotic treatment is warranted. Renal impairment develops in approximately one-third of patients with spontaneous bacterial peritonitis and is postulated to arise as a result of a further reduction in effective arterial blood volume. Cefotaxime has been the most extensively studied antibiotic for this infection. It is considered to be one of the first choice antibiotics because of low toxicity and excellent efficacy. Although parenteral antibiotics are generally used, studies evaluated the efficacy of several oral antibiotics in patients with relatively good clinical conditions. The reported probability of spontaneous bacterial peritonitis recurrence one year after the first attack averaged 40 to 69%. Selective intestinal decontamination with 400 mg norfloxacin per day decreased the overall probability of recurrence from 68% to 20% in 1 year of follow-up.