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INDEX

  • Spontaneous Bacterial Peritonitis
  • Context
  • PATHOPHYSIOLOGY
  • CLINICAL PRESENTATION
  • Diagnostic Process
  • EXCLUDING SECONDARY BACTERIAL PERITONITIS
  • Recommended Treatment
  • TREATMENT: ANTIMICROBIAL THERAPY
  • TREATMENT: ALBUMIN / OTHER CONSIDERATIONS
  • SBP PROPHYLAXIS
  • Quality Of Evidence?
  • Related Information
  • Relevant Resources

Spontaneous Bacterial Peritonitis

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Last Reviewed on Jan 19, 2022
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By Jim Goulding,Aaron Chan

Context

Spontaneous bacterial peritonitis (SBP) is a bacterial infection of ascites without an identifiable source and is defined as polymorphonuclear leukocytes (PMN) count > 250 cells/mm3 and presence of a single organism in ascitic fluid.

  • A potentially fatal but reversible cause of deterioration in patients with advanced cirrhosis and should be suspected in any patient with cirrhosis and ascites.
  • Mortality rates increase by 10% for every hour delay in initiating antimicrobial therapy in patients with cirrhosis who are in septic shock.

PATHOPHYSIOLOGY

  • Intestinal bacterial overgrowth with subsequent translocation to mesenteric lymph nodes with failure of the immune system in part due to diminished opsonic activity.

CLINICAL PRESENTATION

  • Fever (50-75%), abdominal pain (27-72%) or tenderness (30-40%) almost exclusively in context of ascites.
  • Can be asymptomatic in small but significant proportions (up to 13%) of patients.

Diagnostic Process

Indications for paracentesis in cirrhotics with ascites include any of the following:

    • at time of admission (consider asymptomatic SBP).
    • change in clinical status.
    • development of lab abnormalities.
    • during episodes of variceal bleeding, prior to antibiotics.
  • Fluid PMN count > 250 cells/mm3 is the single best test in diagnosing ascitic fluid infection.
  • Ascitic fluid culture should be immediately inoculated at bedside in one aerobic and one anaerobic bottle, prior to initiation of antimicrobial therapy.
  • Due to considerable mortality, there should be low threshold to perform diagnostic abdominal paracentesis even in context of coagulopathy.

EXCLUDING SECONDARY BACTERIAL PERITONITIS

  • Defined as bacterial infection of ascites with surgically treatable intra-abdominal source of infection (e.g., perforated viscus or intra-abdominal abscess) with PMN count > 250 cells/mm3.

Secondary bacterial peritonitis should be suspected if 2 of 3 of the following on paracentesis fluid analysis:

    • Glucose < 2.8mmol/L.
    • Total protein > 0.62mmol/L.
    • LDH > Upper limit of normal for serum.

If above criteria are met OR polymicrobial ascitic culture, perform upright XR/chest to look for free air and consider CT to investigate for cause of secondary bacterial peritonitis.

OTHER INVESTIGATIONS

  • Serum albumin and ascites albumin to confirm portal hypertension (if status unknown).
  • Other studies such as ascites fluid pH have limited utility in the diagnosis of SBP.

Recommended Treatment

TREATMENT: ANTIMICROBIAL THERAPY

  • Monomicrobial infection with Escherichia coli and gram positives (streptococcus, enterococcus) most common organisms.
  • Indications for empiric antimicrobial therapy to be initiated AFTER cultures are obtained if:
    • Fluid PMN > 250 cells/mm3 OR.
    • Clinical signs/symptoms of infection (e.g., fever, abdominal pain/tenderness).
  • In most cases, start with Cefotaxime 2g IV q8h.
    • If nosocomial infection, recent hospitalization, or ICU admission, consider piperacillin-tazobactam or carbapenem +/- vancomycin.
  • Duration of antimicrobial therapy is 5-7 days.
  • Consider repeating diagnostic paracentesis in 48h to assess response.

TREATMENT: ALBUMIN / OTHER CONSIDERATIONS

  • Start Albumin 1.5g/kg at day 1 and 1g/kg at day 3.
  • Consider holding non-selective beta blockers in patients with SBP who develop hypotension (<65mmHg) or AKI.

SBP PROPHYLAXIS

  • In patients with cirrhosis and UGIB, start Ceftriaxone 1g IV q24h until hemorrhage has resolved for maximum of 7 days.
  • Antimicrobial prophylaxis should be also considered in patients with cirrhosis who have low protein ascites (<1.5g/L) and severe renal or liver dysfunction (Child-Pugh >9).

Quality Of Evidence?

Justification

  • Diagnostic value of Fluid PMN count: HIGH. Meta-analysis of prospective studies.
High

Diagnostic value of Fluid pH: LOW. Data from prospective studies published over 20 years ago.

Low
  • Empiric antimicrobial therapy with Cefotaxime: HIGH. Multiple RCTs.
High
  • Effect of albumin on reducing mortality in SBP: HIGH. Multiple RCTs.
High
  • Antibiotic prophylaxis to prevent SBP in cirrhosis: LOW. Low-certainty evidence in recent Cochrane review.
Low

Related Information

OTHER RELEVANT INFORMATION

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