A 45-year-old man with alcohol-related cirrhosis presents with worsening ascites. Diagnostic paracentesis shows ascitic fluid: total protein 2.8 g/dL, SAAG 1.3 g/dL. Two weeks ago he had a SAAG of 1.2 g/dL. He is now febrile with abdominal pain. Diagnostic criteria for spontaneous bacterial peritonitis (SBP) include:

• A Ascitic fluid PMN count ≥500 cells/μL
• B Ascitic fluid polymorphonuclear (PMN) count ≥250 cells/μL ✓
• C Positive ascitic fluid culture in the absence of an intra-abdominal source
• D Ascitic protein <1 g/dL with PMN >100 cells/μL

Explanation

SBP is diagnosed when ascitic fluid PMN count is ≥250 cells/μL (neutrocytic ascites), regardless of whether culture is positive (culture-negative neutrocytic ascites or CNNA is treated the same as SBP). Symptomatic patients with PMN 250–499 may have SBP and require treatment. Cultures are positive in only 40–50% of SBP cases. Third-generation cephalosporins (cefotaxime) are first-line treatment. IV albumin (1.5 g/kg on day 1 and 1 g/kg on day 3) reduces hepatorenal syndrome risk in patients with creatinine >1 mg/dL, bilirubin >4 mg/dL, or BUN >30 mg/dL.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.