Spontaneous bacterial peritonitis

See Peritoneal dialysis-associated peritonitis for PD peritonitis

Background

• 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 Manifestations

• Fever - 70%
• Abdominal pain (diffuse) - 60%
• Altered mental status - 55%
• ~15% of patients have no signs/symptoms

Work-Up

• Ascitic Fluid
  • Cell count, glucose, protein, gm stain, cx (10cc in blood cx bottle), LDH, alk phos
• Consider alternative Dx at the same time

Diagnosis

• 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 tx is only abx without sx
  • Mortality of unnecessary sx in pt w/ 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

Treatment

• Antibiotics
  • SBP
    • Broad-spectrum covering enterobacter (63%), pneumococcus (15%), entercocci (10%)
    • Anaerobes causative agent <1%
      • 3rd-generation cephalosporin is agent of choice:
        • Cefotaxime 2g IV q8hr or Ceftriaxone 1-2g IV q12-24hr
      • If beta-lactam allergy consider ciprofloxacin 400mg IV q12hr
  • Secondary bacterial peritonitis
    • 3rd-generation cephalosporin + metronidazole
    • Surgery
• Albumin
  • Reduces renal failure and hospital mortality
  • 1.5gm/kg at diagnosis; 1gm/kg on day 3

Disposition

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

See Also

Paracentesis Peritoneal dialysis-associated peritonitis

References

• Paracentesis. N Engl J Med 2006; 355