Rosen & Barkin's 5-Minute Emergency Medicine Consult (672 page)

• Routine ascitic fluid assays:
  
  • Cell count and differential:
    
    • Count bands as PMNs
      
  • Total protein
    
  • Albumin
    
  • Culture
    
  • Gram stain
    
  • Optional fluid assays:
    
    • Glucose
      
    • LDH (from lysed PMNs)
      
    • Amylase
      
• Characteristics of ascitic fluid consistent with SBP:
  
  • PMNs >250/mm
    ³
    
  • Diagnosis suggested when:
    
    • WBC >1,000/mm
      ³
      
    • WBC >250/mm
      ³
      with >50% PMNs
      
  • Total protein <1 g/dL
    
  • pH <7.34
    
  • Normal amylase
    
  • Positive culture:
    
    • Only 30–50% of cultures become positive; this rate increases with high volume bedside inoculation of culture bottles
      
  • Positive Gram stain
    
  • Glucose <50 mg/dL
    
  • Ascites LDH > serum LDH
    
  • Lactoferrin >242 shows promise as marker for SBP
    
  • Serum–ascites albumin gradient >1.1 g/dL consistent with portal hypertension
    
  • If hemorrhagic ascites (>10,000 RBC/mm
    ³
    ), subtract 1 PMN/mm
    ³
    for every 250 RBC/mm
    ³
    in ascites fluid interpretation
    
• Blood tests (usually reflect underlying disease):
  
  • CBC with differential
    
  • Basic metabolic panel
    
  • PT/PTT
    
  • LFTs (including albumin)
    
  • Blood cultures
    
  • UA and culture
    

• Abdominal ultrasound:
  
  • Confirms presence of ascites
    
  • Helps guide paracentesis
    
• Chest radiograph
  
• Abdominal radiographs: Flat-plate and upright to evaluate for perforation or obstruction
  
• Water-soluble contrast CT if suspect secondary bacterial peritonitis
  

Surgery consultation to consider exploratory laparotomy if free air on x-ray or extravasation of contrast on CT

• Secondary bacterial peritonitis:
  
  • Due to perforation or abscess
    
  • Polymicrobial Gram stain or 2 of the following:
    
    • Ascites total protein >1 g/dL
      
    • Ascites glucose <50 mg/dL
      
    • Ascites LDH >1/2 upper limit of normal serum LDH or LDH>225
      
  • Orange ascites with bilirubin >6 mg/dL suggests ruptured gallbladder
    
• Acute hepatitis:
  
  • Fever, leukocytosis, abdominal pain ± ascites
    
  • Ascites PMNs <250/mm
    ³
    
• Culture-negative neutrocytic ascites:
  
  • Ascites PMNs >250/mL, culture negative
    
• Monomicrobial non-neutrocytic bacterascites:
  
  • Due to colonization phase of SBP
    
  • Ascites PMNs <250/mm
    ³
    , monomicrobial culture
    
  • Treated like SBP if symptomatic
    
• Polymicrobial bacterascites:
  
  • Due to accidental gut perforation (1 in 1,000 paracenteses)
    
  • Ascites PMNs <250/mm
    ³
    , polymicrobial culture
    
• Pancreatitis:
  
  • Elevated ascites amylase
    
• Peritoneal carcinomatosis or tuberculous peritonitis:
  
  • Secondary bacterial peritonitis criteria with non-PMN predominance and lack of fever
    

TREATMENT

• IV fluids for hypotension
  
• Blood glucose for altered mental status
  
• Supplemental oxygen for respiratory complaints
  

• ABCs
  
• Prompt antibiotic treatment and IV fluids for septic shock
  

• Administer platelets before paracentesis only if platelet count is <20,000/mm
  ³
  
• Give empiric antibiotics immediately after paracentesis for:
  
  • Ascites PMNs >250/mm
    ³
    or
    
  • Temperature >37.8°C or
    
  • Altered mental status or
    
  • Abdominal pain/tenderness or
    
  • Clinical features most consistent with SBP
    
• Antibiotic options:
  
  • Ceftriaxone or cefotaxime
    
  • Ampicillin–sulbactam, piperacillin–tazobactam or aztreonam
    
  • Avoid aminoglycosides, fluoroquinolones
    
  • Add metronidazole for secondary bacterial peritonitis
    
• IV albumin is helpful in preventing renal impairment and reducing mortality in diagnosed SBP
  

• In-hospital noninfection–related mortality is 20%
  
• Can be precursor to hepatorenal syndrome
  
• 1- and 6-mo mortality rates after an episode of SBP are 32% and 69%, respectively
  

• Cefotaxime: 2 g IV q8h
  
• Albumin for high-risk patients: 1.5 g/kg IV on day 1 and 1 g/kg IV on day 3
  

• Ceftriaxone: 2 g IV q8h
  
• Piperacillin–tazobactam: 3.375 g IV q6h
  
• Ampicillin–sulbactam: 1.5–3 g IM/IV q6h
  
• Aztreonam: 0.5–2 g IM/IV q6–12h
  

FOLLOW-UP

• Admit all patients for IV antibiotics and gastroenterology consultation
  
• ICU admission for septic shock or severe hepatic encephalopathy
  

• All patients with suspected or known SBP should be admitted.
  
• If patient refuses admission and has no signs of shock, encephalopathy, azotemia, or GI bleeding, a dose of IV ceftriaxone and a course of oral fluoroquinolones followed by close follow-up may be considered
  

• Hepatology and gastroenterology referral may be indicated
  
• Prophylaxis with norfloxacin or trimethoprim/sulfamethoxazole
  

Gastroenterology or PCP follow-up for patients with SBP

• Rule out secondary bacterial peritonitis first
  
• Bedside inoculation of blood culture bottles with ascitic fluid increases culture yield
  
• Maintain high suspicion for SBP, since many patients are asymptomatic
  

• Grabau CM, Crago SF, Hoff LK, et al. Performance standards for therapeutic abdominal paracentesis.
  Hepatology
  . 2004;40:484–488.
  
• Greenberger NJ, Blumberg RS, Burakoff R.
  Current Diagnosis & Treatment: Gastroenterology, Hepatology, & Endoscopy.
  2nd ed. McGraw-Hill; 2012.
  
• Such J, Runyon BA. Spontaneous bacterial peritonitis.
  Clin Infect Dis
  . 1998;27:669–674.
  
• Wiest R, Krag A, Gerbes A. Spontaneous bacterial peritonitis: Recent guidelines and beyond.
  Gut.
  2012;61(2):297–310.
  
• Wong CL, Holroyd-Leduc J, Thorpe KE, et al. Does this patient have bacterial peritonitis or portal hypertension? How do I perform a paracentesis and analyze the results?
  JAMA
  . 2008;299:1166–1178.
  

See Also (Topic, Algorithm, Electronic Media Element)

• Ascites
  
• GI Bleeding
  
• Hepatitis
  
• Hepatorenal Syndrome
  
• Abdominal Pain
  

We wish to acknowledge the previous authors of this chapter for their contributions on this topic: Michael Schmidt, Amer Aldeen, and Lucas Roseire.

CODES

567.23 Spontaneous bacterial peritonitis

BASICS