Spontaneous bacterial peritonitis

Clinical Manifestations

• Develops in large, clinically obvious ascites 2/2 cirrhosis
• Fever - 70%
• Abdominal pain (diffuse) - 60%
• Altered mental status - 55%
• ~15% of patients have no signs/symptoms!

Diagnosis

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

Distinction of spontaneous from secondary bacterial peritonitis

• Importance
• Mortality of 2o bacterial peritonitis approaches 100 percent if tx is only antibiotics without sx
• Mortality of unncessary ex lap in patient w/ SBP and wrongly suspected 2o bacterial peritonitis ~80%
• Laboratory findings
• Neutrocytic fluid (PMN ≥250) with two or more of following = strong evidence of 2o bacterial peritonitis:
• 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

• Should strongly suspect if ascitic alk phos >240
• Gram Stain
• Large numbers of different bacterial forms
• Imaging
• If evidence of 2o bacterial peritonitis obtain abdominal imaging
• If no evidence of free air or contrast extravasation then surgery is not indicated

Treatment

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

Source

Rosen's, UpToDate, Thomsen TW. Paracentesis. N Engl J Med 2006; 355