Spontaneous bacterial peritonitis

Definition

• Primary infection of the ascitic fluid, diagnosed by ascites fluid with positive culture or with neutrophil count greater than 250

Pathophysiology

• Intestinal bacterial overgrowth with increased intestinal permeability leads to translocation to intestinal lymph notes and bloodstream, which results in hematogenous seeding to ascitic fluid
• Only occurs in portal hypertension, not in other causes of ascites

Bacteriology

• Escherichia coli (43%)
• Klebsiella pneumoniae (11%)
• Streptococcus pneumoniae (9%)
• Other streptococcal species (19%)
• Enterobacteriaceae (4%)
• Staphylococcus (3%)
• Pseudomonas (1%)
• Miscellaneous (10%)
  • Aeromonas hydrophila, in Korea

Risk Factors

• Previous history of SBP
• Upper GI bleed
• Low sciatic protein
• Child-Pugh class

Presentation

• Asymptomatic in 10%
• Fever (70%)
• Abdominal pain (60%)
• Hepatic encephalopathy (50%)
• Abdominal tenderness, usually without rigidity (50%)
• Diarrhea (30%)
• Ileus (30%)
• Shock (20%)
• Hypothermia (15%)

Investigations

• Labs
  • Ascitic fluid for cell count and culture
    • Neutrophil count < 250 rules it out
    • Culture usually monomicrobial
  • Repeat paracentesis at 48h if ongoing concern
• Imaging
• Other

Management

• Acute
  • Ceftriaxone 1-2g IV q24h
• Chronic
  • Prophylaxis after a single episode
    • Septra SS PO daily
    • Norfloxacin
• Some role for primary prophylaxis, I think?

Prognosis

• In-hospital mortality of about 33% in hospital
• 58% 6-month mortality