Definition of Neutroascites
Neutroascites is defined as an ascitic fluid polymorphonuclear leukocyte (PMN) count ≥250 cells/mm³, which is the diagnostic threshold for spontaneous bacterial peritonitis (SBP) in patients with cirrhotic ascites. 1
Diagnostic Criteria
The key diagnostic parameter is:
- Ascitic PMN count ≥250/mm³ without evidence of an intra-abdominal surgically treatable source of infection 1
Important Adjustments for Bloody Ascites
- If red blood cells (RBCs) are present in the ascitic fluid, the PMN count must be adjusted by subtracting 1 PMN per 250 RBCs/mm³ to avoid false-positive results 1
Clinical Context and Variants
Culture-Negative Neutrocytic Ascites
- Approximately 40% of patients with ascitic PMN count ≥250/mm³ are culture-negative even with appropriate culture techniques 1
- These patients show a clinical course similar to culture-positive cases and require empirical antibiotic therapy 1
Monomicrobial Non-Neutrocytic Bacterascites
- This variant presents with a single bacterial strain cultured but PMN count <250/mm³ 1
- Represents bacterial colonization rather than true infection 1
- Asymptomatic patients typically do not require treatment as most resolve spontaneously 1
Critical Threshold for Secondary Peritonitis
- PMN count >1,000/mm³ should raise suspicion for secondary bacterial peritonitis from intestinal perforation or abscess, which carries 50-80% mortality and may require surgical intervention 1
Common Pitfall
Do not confuse neutroascites (elevated PMN in ascitic fluid) with neutropenic enterocolitis, which is a completely different entity occurring in neutropenic cancer patients with bowel wall inflammation and systemic neutropenia (absolute neutrophil count ≤500 cells/mm³ in blood). 1, 2