Spontaneous Bacterial Peritonitis

16 Nov
November 16, 2017

Definition: Acute infection of the ascitic fluid in a patient with liver disease without another source of infection

Epidemiology: (Runyon 1988, Runyon 1988, Borzio 2001)

  • Incidence
    • 10-25% risk of at least one episode per year
    • 20% risk in those with ascites admitted to the hospital
  • Historically, mortality ~ 50%

Pathophysiology:

  • Not completely understood
  • Increased portal systemic hypertension
    • Causes mucosal edema of the bowel wall
    • Increases transmural migration of enteric organisms into the ascitic fluid
  • Impaired phagocytic function in the liver
  • Impaired immunologic activity in ascitic fluid

Presentation:

  • Classic triad: fever, abdominal pain and increasing ascites. Presence of all three components uncommon
  • Symptoms
    • Fever or chills
    • Abdominal pain
    • Abdominal swelling
    • Fatigue
    • Malaise
  • Signs
    • Abdominal tenderness variable
      • Typically diffuse
      • Can be mild without peritoneal signs
      • Can be severe with rebound and/or guarding
    • Abdominal distension
    • Altered mental status (from hepatic encephalopathy)

Diagnostics:

  • Obtaining an ascitic fluid sample is critical in making the diagnosis
  • Serum blood tests (i.e. WBC, CRP, ESR) are not helpful in making this diagnosis
  • Due to variable presentations and considerable mortality associated with SBP, consideration should be made to perform paracentesis on ALL patients with ascitic fluid who are being admitted (Gaetano 2016)
  • Diagnostic paracentesis (EM: RAP HD)
  • Paracentesis (DrER.tv)

    Ascitic fluid assays

    • Cell count
      • Look for WBC > 250-500 cells/mm3 or neutrophil count > 250 cells/mm3
      • Peritoneal dialysis patients: neutrophil count > 100 cells/mm
    • pH < 7.34 more common in SBP (Wong 2008)
    • Ascitic fluid gram stain (rarely positive) and culture
  • If patient has fever (temp > 100oF) or abdominal pain/tenderness, empiric antibiotics should be given even if neutrophil count < 250 cells/mm3

Management:

  • Antibiotics
    • Most common bacterial causes: E. Coli, S. Pneumoniae, Enterococci
    • 3rd Generation Cephalosporin covers vast majority of cases
      • Ceftriaxone 25 mg/kg up to 2 gm daily
      • Cefotaxime 25 mg/kg up to 1 gm Q8
    • Alternate antibiotic choices
      • Ciprofloxacin 400mg IV BID
      • Levofloxacin 750mg IV daily
      • Piperacillin/Tazobactam 4.5g IV TID
      • Ertapenem 1g IV qD
      • Imipenem/Cilastatin 500mg IV QID
  • Albumin Infusion (Runyon 2012)
    • Recommended by American Association for the Study of Liver Disease (AASLD) in specific subgroups with SBP
      • Presence of any of the following should prompt albumin administration
      • Serum creatinine > 1 mg/dL
      • Blood urea nitrogen (BUN) > 30 mg/dL
      • Total Bilirubin > 4 mg/dL
    • Impact of albumin infusion (Sort 1999)
      • 25% reduction in renal failure
      • 20% reducing n mortality
    • Dose
      • 1.5 grams/kg within 6 hours
      • 1.0 grams/kg on day 3 of treatment
  • Patients with a single episode of SBP should be considered for antibiotic prophylaxis (with norfloxacin, ciprofloxacin or TMP/SMX) (Runyon 2012)

Approach to the Diagnosis and Treatment of SBP (University of Washington)

Take Home Points:

  • SBP is a difficult diagnosis to make because presentations are variable. Consider a diagnostic paracentesis in all patients presenting to the ED with ascites from cirrhosis
  • An ascites PMN count > 250 cells/mm3 is diagnostic of SBP but treatment should be considered in any patient with ascites and abdominal pain or fever
  • Treatment of SBP is with a 3rd generation cephalosporin with the addition of albumin infusion in any patient meeting AASLD criteria (Cr > 1.0 mg/dL, BUN > 30 mg/dL or Total bilirubin > 4 mg/dL)

For More on this Topic Checkout:

References:

  1. Runyon BA et al. Ascitic fluid analysis in malignancy‐related ascites. Hepatology 1988; 8(5):1104-1109. PMID: 3417231
  2. Runyon BA. Spontaneous bacterial peritonitis: An explosion of information. Hepatology 1988; 8: 171–175. PMID: 3338704
  3. Borzio M et al. Bacterial infection in patients with advanced cirrhosis: a multicentre prospective study. Dig Liver Dis 2001; 33(1): 41-48. PMID: 11303974
  4. Gaetano et al. The benefit of paracentesis on hospitalized adults with cirrhosis and ascites. Journal of Gastroenterology and Hepatology 2016. PMID: 26642977
  5. Wong CL et al. Does this patient have bacterial peritonitis or portal hypertension? How do I perform a paracentesis and analyze the results? JAMA 2008; 299(10):1166-78. PMID: 18334692
  6. Runyon BA. Management of Adult Patients with Ascites Due to Cirrhosis: Update 2012. AASLD Practice Guideline. Link
  7. Sort P et al. Intravenous albumin in patients with cirrhosis and spontaneous bacterial peritonitis. NEJM 1999; 341: 1773-4. PMID: 10432325

Post Peer Reviewed By: Salim Rezaie (Twitter: @srrezaie)

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Anand Swaminathan

Clinical Assistant Professor of Emergency Medicine at Bellvue/NYU
REBEL EM Associate Editor and Author

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3 replies
  1. DG says:

    We have two albumin concentrations in my hospital, 25% and 5%. I’ve only used the 25% concentration with the 1.5 mg/kg on Day 1 as above while my patient is waiting to get admitted. I’ve read through some SBP FOAM posts and they never mention the concentration of albumin to use. Is this because it is considered “common knowledge” to only use the 25% concentration? Are other concentrations available and when would we use them?

    Reply
    • Salim Rezaie says:

      Hi there David,
      You are correct there are 5% and 25% concentrations. As a general rule, 5% is intended to restore plasma volume (resuscitation) while the 25% will raise oncotic pressure (decrease renal failure). Hope this helps.

      Salim

      Reply

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