What is the diagnostic criterion for spontaneous bacterial peritonitis and the recommended initial management?

• A. PMN count in ascitic fluid ≥250 cells/µL; start empiric antibiotics (e.g., cefotaxime) and administer IV albumin to prevent renal dysfunction in selected patients
• B. Positive ascitic fluid culture
• C. Fever and abdominal pain
• D. Elevated ascitic protein

Answer: (A)

The main concept is that spontaneous bacterial peritonitis is diagnosed by an ascitic fluid neutrophil count of 250 cells per microliter or higher, regardless of whether the culture is positive. This threshold is used because neutrophil predominance in the ascitic fluid reliably indicates intra-abdominal infection in a cirrhotic patient, and waiting for culture results can delay life-saving therapy.

Once SBP is suspected or confirmed by that neutrophil criterion, the priority is immediate empiric treatment with broad-spectrum antibiotics, typically a third-generation cephalosporin such as cefotaxime. Starting antibiotics right away improves survival because delays are associated with worse outcomes.

Administering intravenous albumin is added in selected patients to reduce the risk of renal dysfunction and death. Albumin helps maintain intravascular volume and renal perfusion, particularly in patients with signs of renal impairment or more severe disease (for example, higher bilirubin or creatinine values). A common approach is to give albumin early in therapy to prevent renal complications.

The other options don’t fit because a positive culture can occur without SBP and is not required for diagnosis, fever and abdominal pain are nonspecific and not reliable diagnostic criteria, and simply elevated ascitic protein does not diagnose SBP.