A cirrhotic patient with ascites has an ascitic fluid white‑cell count of 2.28 × 10⁹/L (≈2 300 cells/mm³) with 69 % neutrophils; what is the diagnosis and how should it be managed?

Diagnosis: Spontaneous Bacterial Peritonitis (SBP)

This patient has confirmed spontaneous bacterial peritonitis and requires immediate empirical antibiotic therapy with cefotaxime plus intravenous albumin without waiting for culture results. 1, 2

Diagnostic Confirmation

The ascitic fluid analysis definitively establishes SBP:

• Absolute neutrophil count = 1,573 cells/mm³ (calculated as 2,280 cells/mm³ × 0.69), which far exceeds the diagnostic threshold of ≥250 cells/mm³ 1, 2, 3
• The neutrophil predominance (69%) with elevated total WBC confirms bacterial peritonitis rather than alternative diagnoses like tuberculous peritonitis (which shows lymphocyte predominance) 2, 4
• This PMN count yields a positive likelihood ratio of 10.6 for SBP, making the diagnosis essentially certain 1

Critical pitfall to avoid: Do not wait for culture results to initiate treatment—the elevated PMN count alone is sufficient, and each hour of delay increases in-hospital mortality by 3.3% 1, 2

Immediate Management Algorithm

Step 1: Initiate Antibiotics Immediately

First-line therapy: Cefotaxime 2g IV every 8 hours for 5 days 1, 2, 3

• Alternative regimen: Amoxicillin-clavulanic acid if cefotaxime unavailable 2
• Do NOT use quinolones if the patient is already on quinolone prophylaxis, in nosocomial SBP, or in areas with high quinolone resistance 2
• Oral ofloxacin 400mg twice daily may be considered only in uncomplicated cases without vomiting, shock, hepatic encephalopathy ≥grade II, or creatinine >3 mg/dL 2, 3

Step 2: Administer Albumin Therapy

Albumin 1.5 g/kg body weight IV within 6 hours of diagnosis, followed by 1.0 g/kg on day 3 2, 3

• This regimen reduces mortality from 29% to 10% and decreases type 1 hepatorenal syndrome from 30% to 10% 2, 3
• Albumin therapy is as essential as antibiotics and should never be omitted 2

Step 3: Obtain Cultures Before Antibiotics

• Inoculate at least 10 mL of ascitic fluid into aerobic and anaerobic blood culture bottles at bedside before starting antibiotics (increases sensitivity to >90%) 2
• Obtain simultaneous blood cultures 2
• However, do not delay antibiotics while waiting for culture bottles—start treatment immediately after paracentesis 1, 2

Step 4: Monitor Treatment Response at 48 Hours

Perform repeat paracentesis at 48 hours to assess treatment efficacy 2

• Treatment success: PMN count decreases to <25% of pre-treatment value (i.e., <393 cells/mm³ in this case) with clinical improvement 2
• Treatment failure: PMN count fails to decrease by ≥25% or clinical deterioration persists 1, 2

Step 5: Management of Treatment Failure

If PMN count remains elevated or clinical status worsens at 48 hours:

• Consider resistant organisms requiring antibiotic modification based on culture sensitivities 2
• Rule out secondary bacterial peritonitis with CT imaging and surgical consultation 2
• Secondary peritonitis typically shows ascitic protein >1 g/dL, LDH higher than serum levels, glucose <50 mg/dL, or multiple organisms on Gram stain 2

Additional Diagnostic Considerations

To differentiate SBP from secondary peritonitis, measure:

• Ascitic fluid total protein, LDH, and glucose 2
• Perform Gram stain (multiple organisms suggest secondary peritonitis) 2
• Calculate serum-ascites albumin gradient (SAAG) if not already done 1

Prognosis and Follow-up

• In-hospital mortality remains approximately 20% despite appropriate treatment 1, 2
• One-year survival after SBP hospitalization is only 34% 1
• All patients recovering from SBP should be evaluated for liver transplantation if not already assessed 1
• Secondary prophylaxis with norfloxacin or trimethoprim-sulfamethoxazole should be initiated after resolution to prevent recurrence 1

Common pitfall: Culture-negative neutrocytic ascites (PMN >250/mm³ with negative culture) has identical morbidity and mortality to culture-positive SBP and must be treated identically 1, 4