Diagnosis of Spontaneous Bacterial Peritonitis

Spontaneous bacterial peritonitis (SBP) is an infection of ascites that occurs in the absence of an apparent source of infection. Bacterial translocation from the gut plays an important role in developing SBP. Bacteria that eventually cause SBP can also originate from sites other than the gut via bacteremic seeding. The vast majority of patients with SBP have advanced cirrhosis. Although SBP patients develop symptoms such as fever and abdominal pain, some have no signs or symptoms of infection at the time of diagnosis. Early diagnosis is a key issue in the management of SBP. Patients with ascites admitted to the hospital should undergo abdominal paracentesis. The ascitic fluid should be tested for aerobic and anaerobic cultures, white blood cell count and differential, and fluid chemistries. A confirmed SBP diagnosis requires a positive ascitic fluid bacterial culture, with an elevated ascitic fluid absolute polymorphonuclear leukocyte count and without any evidence of an intra-abdominal surgically treatable source. Pathogens commonly associated with SBP include Escherichia coli, streptococcal species, and Klebsiella pneumoniae. As appropriate therapy is necessary for a good prognosis, a clear distinction is crucial (or mandatory) between secondary bacterial peritonitis and SBP.