Spontaneous bacterial peritonitis

Revision as of 08:19, 30 May 2015 by Rossdonaldson1 (talk | contribs) (Spontaneous versus secondary bacterial peritonitis)

See Peritoneal dialysis-associated peritonitis for PD peritonitis


  • Abreviation: SBP
  • Develops in large, clinically obvious ascites 2/2 cirrhosis
    • Normal flora translocate across the bowel wall into the peritoneum
  • 30% of ascitic pts will develop SBP in a given year
  • There is no platelet count or INR that is a contraindication to paracentesis

Clinical Features

Differential Diagnosis

Diffuse Abdominal pain


Consider alternative diagnoses at the same time

SBP Work-Up of Ascitic Fluid via Paracentesis

  • Cell count with differential
  • Gram stain
  • Culture (10cc in blood culture bottle)
  • Glucose
  • Protein

Fluid Analysis

  • Paracentesis results supporting a diagnosis of SBP:
    • Total WBC >500
    • Absolute neutrophil count > 250
    • Bacteria on gram stain (single type)
    • SAAG > 1.1
    • Protein < 1, Glucose > 50 (otherwise concern for secondary bacterial peritonitis)

Spontaneous versus secondary bacterial peritonitis

  • Importance of distinction
    • Mortality of secondary bacterial peritonitis ~100% if treatment is only antibiotics without surgery
    • Mortality of unnecessary surgery in patients with SBP ~80%
  • Laboratory findings
    • Secondary bacterial peritonitis strongly suggested by:
      • Neutrocytic fluid (PMN ≥250) w/ two or more of the following:
        • Total protein concentration >1 g/dL (10 g/L)
        • Glucose concentration <50 mg/dL (2.8 mmol/L)
        • LDH greater than upper limit of normal for serum
      • Ascitic alk phos >240
      • Gram stain
        • Large numbers of different bacterial forms
  • Imaging
    • If evidence of secondary bacterial peritonitis obtain abdominal imaging
      • If no evidence of free air or contrast extravasation then surgery is not indicated



  • SBP
    • Broad-spectrum covering enterobacter (63%), pneumococcus (15%), entercocci (10%)
    • Anaerobes causative agent <1%
      • 3rd-generation cephalosporin is agent of choice:
      • If beta-lactam allergy consider ciprofloxacin 400mg IV q12hr
  • Secondary bacterial peritonitis
    • 3rd-generation cephalosporin + metronidazole
    • Surgery


  • Reduces renal failure and hospital mortality
  • 1.5gm/kg at diagnosis; 1gm/kg on day 3


  • Can consider discharge w/ PO abx if pt has mild, uncomplicated disease and close f/u

See Also


  • Paracentesis. N Engl J Med 2006; 355