What diagnosis and treatment are indicated for ascitic fluid with elevated nucleated cell count, neutrophil predominance, and a high red blood cell count?

Spontaneous Bacterial Peritonitis (SBP) Requiring Immediate Antibiotic Therapy

This peritoneal fluid analysis demonstrates spontaneous bacterial peritonitis with a polymorphonuclear neutrophil (PMN) count of 1794 cells/mm³ (73% of 2458 total nucleated cells), which far exceeds the diagnostic threshold of ≥250 cells/mm³ and mandates immediate empiric antibiotic treatment with cefotaxime 2g IV every 8 hours plus albumin therapy. 1, 2, 3

Diagnostic Confirmation

Your patient's ascitic fluid shows:

• Total nucleated cells: 2458 cells/mm³
• Neutrophils: 73% = approximately 1794 PMN/mm³ (well above the 250 cells/mm³ threshold)
• RBC: 2177 cells/mm³ (indicates some hemorrhagic component but does not alter SBP diagnosis)

• The PMN count of 1794 cells/mm³ is more than 7-fold higher than the diagnostic threshold of ≥250 cells/mm³ required for SBP diagnosis, making this a clear-cut case. 1, 2, 3
• The neutrophil predominance (73%) with elevated total nucleated cells reflects failure of peritoneal macrophages to eradicate invading bacteria, which is the hallmark cellular pattern of SBP. 2
• The presence of RBCs (2177 cells/mm³) likely represents traumatic tap or hemorrhagic ascites but does not change the diagnosis or management of SBP. 4

Immediate Treatment Protocol

First-Line Antibiotic Therapy

• Initiate cefotaxime 2g IV every 8 hours immediately without waiting for culture results—the PMN count alone is sufficient to start treatment. 1, 3
• A 5-day course of antibiotic therapy is as effective as 10 days of treatment. 3
• Alternative regimens include amoxicillin-clavulanic acid if cefotaxime is unavailable, but avoid quinolones if the patient is already on prophylaxis or in areas with high quinolone resistance. 3

Essential Albumin Therapy

• Administer IV albumin 1.5 g/kg body weight within 6 hours of diagnosis, followed by 1.0 g/kg on day 3. 1, 5, 3
• This albumin regimen reduces mortality from 29% to 10% and decreases type 1 hepatorenal syndrome from 30% to 10%. 5, 3
• Albumin therapy is not optional—it significantly improves survival and should be given to all SBP patients. 3

Additional Diagnostic Testing

To distinguish SBP from secondary peritonitis (which would require surgical intervention), order:

• Ascitic fluid total protein, LDH, and glucose to help differentiate SBP from secondary peritonitis (SBP typically shows protein <1 g/dL, LDH less than serum, glucose ≥50 mg/dL). 1
• Gram stain to assess for multiple organisms (suggests secondary peritonitis). 1
• Culture ascitic fluid in blood culture bottles at bedside before antibiotics to increase sensitivity to >90%, though treatment should not be delayed for culture results. 3

Monitoring Treatment Response

• Perform repeat paracentesis at 48 hours to assess treatment efficacy—treatment success is defined as a decrease in ascitic PMN count to <25% of the pre-treatment value (in this case, <449 cells/mm³). 3, 6
• In SBP, the neutrophil count should decrease exponentially with a half-life of approximately 34 hours after antibiotic therapy is started. 6
• If the PMN count fails to decrease by at least 25% or increases, suspect treatment failure due to resistant bacteria or secondary bacterial peritonitis requiring CT imaging and surgical consultation. 3, 6

Critical Pitfalls to Avoid

• Do not delay antibiotic therapy—each hour of delay increases in-hospital mortality by 3.3% in cirrhotic patients with septic shock. 3
• Do not wait for culture results to initiate treatment, as the PMN count alone is diagnostic. 2, 3
• Do not omit albumin therapy—it is as important as antibiotics for reducing mortality. 5, 3
• If the patient fails to improve or the repeat PMN count does not decrease appropriately, strongly consider secondary bacterial peritonitis (from perforated viscus) and obtain CT imaging with surgical consultation. 1, 3

Prognosis

• SBP carries approximately 20% hospital mortality despite infection resolution with appropriate treatment. 3
• Early appropriate antibiotic treatment combined with albumin therapy significantly improves survival compared to antibiotics alone. 3