Spontaneous Bacterial Peritonitis (SBP) – Patricia Checinski


  • Infection of ascitic fluid without evidence of a surgical intra-abdominal source
  • Presentation: fever, abdominal pain, encephalopathy, renal failure, acidosis, or leukocytosis, though may present with only one of the aforementioned symptoms



  • Any pt w/cirrhosis and ascites who is admitted should have diagnostic paracentesis to rule out SBP. Delaying paracentesis > 12 hours is associated with a 2.7-fold increase in mortality.
  • Obtain cell count with diff. Calculate the PMNs: total nucleated cells x % neutrophils.
  • PMNs > 250 cells is diagnostic of SBP. If there are greater than 100k RBCs, you should correct for them: for every 250 RBCs, subtract 1 PMN
  • A positive ascitic bacterial culture is diagnostic and should be treated regardless of PMN count. You will frequently see culture-negative SBP (neutrocytic ascites)
  • The absence of secondary causes of bacterial peritonitis is also required for diagnosis, but is assumed in pts w/ cirrhosis and known ascites (see below if concerned for secondary bacterial peritonitis)



  • Immediately start empiric antibiotics.
  • Guidelines recommend cefotaxime IV 2gm q8 hours for 5 days, but we commonly use ceftriaxone IV 2gm q24h for 5-7 days at VUMC and Nashville VA.
    • Most common culprits (E. coli, Klebsiella, streptococcal species, staphylococcal species)
    • If SBP developed while on ppx, hospital admission within 90 days or diagnosed >48 hours of admission, consider zosyn or meropenem
  • IV albumin 1.5 g/kg on day 1 and 1g/kg on day 3
  • Discontinue beta-blockers once SBP develops and do not restart until SBP is completely treated, Na >130, BP is satisfactory (as noted above), and no AKI
  • PPI’s  risk for SBP in pts w/ cirrhosis, and should be reviewed for appropriateness (GERD, hx PUD, RYGB with anastamotic ulcers) and discontinued if not needed
  • It is not always necessary to perform repeat paracentesis to confirm resolution of infection or down trending cell counts, but this is attending-dependent and may be performed
  • Paracentesis should be repeated if pt continues to have signs or symptoms of infection
    • PMN < 250 cells/ mm3 do not restart antibiotics
    • PMN > pre-treatment PMN count look for secondary source (hollow viscus injury or loculations), or reconsider choice of antibiotic
    • PMN < pre-treatment PMN count but >250 cells/mm3 continue abx, repeat tap in 48 hrs

Prophylaxis: Three Indications

  • Inpatient with GI bleed ceftriaxone 1g daily followed by ciprofloxacin 500mg BID (preferred) or Bactrim one DS tablet BID once able to take PO, for total of 5-7 days.
  • Outpatient lifelong ppx for patients with prior SBP (Bactrim DS tab daily or cipro 500mg daily). Alternatives: cefdinir 300mg qd and augmentin 875/125qd—only use if contraindications to the others and would discuss with hepatology team
  • Outpatient lifelong ppx for patients with ascitic protein < 1.5 AND
    • Child Pugh Class C cirrhosis + Bili > 4


    • Renal Dysfunction (Cr > 1.2, Na <125, OR BUN > 25)


If suspicion is high for secondary bacterial peritonitis:

  • Examine serum-ascites albumin gradient (SAAG). SBP develops in pts with portal hypertension, defined by SAAG > 1.1 g/dL. SBP is unlikely if SAAG is < 1.1 g/dL.
  • Runyon’s Criteria to distinguish, requires 2/3 criteria below (protein, glucose, LDH):
  • While not particularly sensitive, an ascitic leukocyte count of 5-10k should prompt consideration of secondary peritonitis
  • Amylase from fluid can also be helpful to point towards pancreatic ascites, while bilirubin can indicate gallbladder perforation. Peritoneal fluid CEA and alkaline phosphatase can additionally help identify hollow viscus injury.
  • Evaluate with cross-sectional imaging and surgical consultation as appropriate




Protein (g/dL)

< 1

> 1

Glucose (mg/dL)


< 50


Elevated, but < 225

> 225