Spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is a bacterial infection of ascitic fluid in patients with decompensated cirrhosis. The modifier 'spontaneous' distinguishes this from surgical peritonitis. The infecting organisms are usually enteric gram-negatives which have translocated from the bowel. Symptoms of infection occur in most patients with SBP, including fever, abdominal pain, mental status changes, and ileus. A high index of suspicion should exist for SBP in patients with cirrhosis and ascites. Diagnostic abdominal paracentesis can be undertaken with minimal risk and should be performed in all patients admitted to the hospital, during times of worsening clinical appearance, or when gastrointestinal bleeding occurs. The ascitic fluid polymorphonuclear cell count is the most sensitive test in evaluating for infection. Cultures of the ascitic fluid are helpful in identifying the organism and are best performed by bedside injection of blood culture bottles. Ascites total protein, lactate dehydrogenase, and glucose levels can assist in distinguishing SBP from secondary peritonitis. Empirical therapy is recommended after paracentesis if suspicion for infection exists. Cefotaxime is the best-studied antibiotic for this purpose and has excellent penetration into ascites with no nephrotoxicity. Prophylaxis should be limited to high-risk settings. Mortality rates in SBP have declined dramatically, largely due to earlier detection and improved therapy.