Spontaneous bacterial peritonitis

Background

• Develops in large, clinically obvious ascites 2/2 cirrhosis
  • Normal flora translocate across the bowel wall into the peritoneum
• 30% of ascitic pts will develop SBP in a given year

Clinical Manifestations

1. Fever - 70%
2. Abdominal pain (diffuse) - 60%
3. Altered mental status - 55%
4. ~15% of patients have no signs/symptoms

Work-Up

1. Ascitic Fluid
   1. Cell count, glucose, protein, gm stain, culture, LDH, alk phos

Diagnosis

1. Paracentesis results supporting a diagnosis of SBP:
   1. Absolute neutrophil count > 250PMNs/microL
   2. SAAG > 1.1
   3. Total protein < 1 and Glucose > 50 (otherwise concern for 2^o bacterial peritonitis)
2. There is no platelet count or INR that is a contraindication to paracentesis

Spontaneous versus secondary bacterial peritonitis

1. Importance of distinction
   1. Mortality of secondary bacterial peritonitis ~100% if tx is only abx without sx
   2. Mortality of unnecessary sx in pt w/ SBP ~80%
2. Laboratory findings
   1. Secondary bacterial peritonitis strongly suggested by:
      1. Neutrocytic fluid (PMN ≥250) w/ two or more of the following:
         1. Total protein concentration >1 g/dL (10 g/L)
         2. Glucose concentration <50 mg/dL (2.8 mmol/L)
         3. LDH greater than upper limit of normal for serum
      2. Ascitic alk phos >240
      3. Gram Stain
         1. Large numbers of different bacterial forms
3. Imaging
   1. If evidence of secondary bacterial peritonitis obtain abdominal imaging
      1. If no evidence of free air or contrast extravasation then surgery is not indicated

Treatment

1. Antibiotics
   1. SBP
      1. Broad-spectrum covering gram + and gram -
         1. 3rd-generation cephalosporin is agent of choice:
            1. Cefotaxime 2g IV q8hr or Ceftriaxone 1-2g IV q12-24hr
         2. If beta-lactam allergy consider ciprofloxacin 400mg IV q12hr>
   2. 2ndary bacterial peritonitis
      1. 3rd-generation cephalosporin + metronidazole
      2. Surgery
2. Albumin
   1. Decreases incidence of renal failure
   2. 1.5g/kg at time of diagnosis and 1g/kg on day 3

Source

• Rosen's
• UpToDate
• Paracentesis. N Engl J Med 2006; 355