What is the recommended empirical management for spontaneous peritonitis?

Empirical Management of Spontaneous Bacterial Peritonitis

Start intravenous cefotaxime 2g every 6-8 hours (or ceftriaxone 2g every 24 hours) immediately upon diagnosis, combined with intravenous albumin 1.5 g/kg at diagnosis and 1 g/kg on day 3. This regimen reduces mortality from 29% to 10% and prevents hepatorenal syndrome 1, 2.

Diagnostic Confirmation Before Treatment

Initiate empirical antibiotics immediately when ascitic fluid polymorphonuclear (PMN) count exceeds 250/mm³, without waiting for culture results 1, 2.

• Even with PMN count <250/mm³, start empirical antibiotics if fever >37.8°C, abdominal pain, tenderness, or unexplained hepatic encephalopathy or renal impairment are present 1.
• Obtain ascitic fluid cultures by inoculating at least 10 mL into blood culture bottles at bedside before antibiotics, and simultaneously obtain blood cultures 2, 3.
• Culture-negative neutrocytic ascites (PMN >250/mm³ with negative culture) should be treated identically to culture-positive SBP 2.

First-Line Antibiotic Regimen

Third-generation cephalosporins are the gold standard for community-acquired SBP 1:

• Cefotaxime 2g IV every 6-8 hours for 5 days achieves 77-98% resolution rates and is the most extensively studied regimen 1, 2, 4.
• Ceftriaxone 2g IV every 24 hours for 5 days is equally effective with 73-100% resolution rates 1, 5.
• A 5-day course is as effective as 10-day treatment 1, 2, 4.

Alternative Regimens for Specific Scenarios

• Oral ofloxacin 400mg twice daily can substitute for IV cefotaxime in uncomplicated SBP without prior quinolone exposure, vomiting, shock, grade II or higher hepatic encephalopathy, or renal failure 1, 2.
• Amoxicillin-clavulanic acid shows similar resolution rates to cefotaxime 1.
• Avoid quinolones in patients already on quinolone prophylaxis, in areas with high quinolone resistance, or in nosocomial SBP 1, 2.

Critical Albumin Therapy

Albumin administration is essential and significantly reduces mortality and hepatorenal syndrome 1, 2, 3:

• Give 1.5 g/kg body weight within 6 hours of diagnosis, followed by 1.0 g/kg on day 3 1, 2, 3.
• This reduces type 1 hepatorenal syndrome from 30% to 10% and mortality from 29% to 10% 1, 2.
• Albumin is particularly critical in patients with baseline serum bilirubin ≥68 μmol/L (4 mg/dL) or creatinine ≥88 μmol/L (1 mg/dL) 1.

Nosocomial SBP: Different Approach Required

For nosocomial SBP, use broader-spectrum antibiotics due to high rates of third-generation cephalosporin resistance 6:

• Meropenem 1g IV every 8 hours plus daptomycin 6 mg/kg/day is significantly more effective than ceftazidime (86.7% vs 25% resolution rate) 6.
• Third-generation cephalosporins alone have unacceptably low efficacy in nosocomial SBP 6.

Monitoring Treatment Response

Perform repeat paracentesis at 48 hours to assess treatment efficacy 1, 2, 3:

• Treatment success is defined as ascitic PMN count decreasing to <25% of pre-treatment value with clinical improvement 1, 2, 3.
• Treatment failure is suspected if PMN count fails to decrease by at least 25%, or if clinical signs worsen 1, 2, 3.

Management of Treatment Failure

If treatment fails after 48 hours, consider these possibilities 1:

• Resistant bacteria: Change antibiotics based on culture sensitivities or escalate empirically to broader-spectrum agents 1, 2.
• Secondary bacterial peritonitis: Suspect if PMN count >1,000/mm³, multiple organisms on Gram stain/culture, ascitic protein ≥1 g/dL, ascitic LDH above normal serum upper limit, ascitic glucose ≤50 mg/dL, or PMN count doesn't drop after 48 hours of treatment 1.
• Obtain abdominal CT imaging if secondary peritonitis suspected 1.
• Check ascitic CEA (>5 ng/mL) and alkaline phosphatase (>240 U/L) to help differentiate secondary from spontaneous peritonitis 1.

Critical Pitfalls to Avoid

• Never delay antibiotics waiting for culture results—each hour of delay increases mortality by 3.3% in septic shock 2.
• Do not use lower ceftriaxone doses: Use 2g daily, not 1g daily, as lower doses may result in worse outcomes 7.
• Do not skip albumin therapy—it is as important as antibiotics for reducing mortality 1, 2, 3.
• Do not use quinolones in patients already on quinolone prophylaxis—use cefotaxime or amoxicillin-clavulanic acid instead 1, 2.
• Perform diagnostic paracentesis in all hospitalized cirrhotic patients with ascites, even without symptoms, as 16% of SBP cases are asymptomatic 2.

Prognosis

• SBP carries approximately 20% hospital mortality despite infection resolution 1, 2, 3.
• Early appropriate antibiotic treatment combined with albumin therapy significantly improves survival 2, 3.
• Ineffective response to first-line treatment is a strong independent predictor of 90-day mortality 6.