What is the recommended management for a patient with Spontaneous Bacterial Peritonitis (SBP)?

Management of Spontaneous Bacterial Peritonitis (SBP)

Start IV antibiotics immediately upon diagnosis (ascitic fluid PMN >250/mm³) without waiting for culture results, and administer IV albumin (1.5 g/kg at diagnosis, then 1.0 g/kg on day 3) to reduce mortality from 29% to 10% and prevent hepatorenal syndrome. 1

Immediate Diagnostic Steps

• Perform diagnostic paracentesis in all hospitalized cirrhotic patients with ascites, even without symptoms, as 16% of SBP cases are asymptomatic 2
• Obtain ascitic fluid and send for cell count with differential (PMN count is diagnostic) 1, 2
• Inoculate at least 10 mL of ascitic fluid into blood culture bottles at bedside before starting antibiotics to increase culture sensitivity to >90% 2
• Obtain blood cultures simultaneously before antibiotic initiation 2
• SBP is diagnosed when ascitic fluid PMN count >250/mm³, regardless of culture results 1, 2

First-Line Antibiotic Therapy

Community-Acquired SBP

• Cefotaxime 2g IV every 8-12 hours for 5-7 days is the gold standard first-line treatment with 77-98% resolution rates 1, 3, 4, 5
• Alternative: Ceftriaxone 1-2g IV every 12-24 hours 3
• For uncomplicated cases in clinically stable patients: Oral ofloxacin 400mg every 12 hours or oral ciprofloxacin 500mg every 12 hours after 2 days of IV therapy 3, 2
• Amoxicillin-clavulanic acid (1g/0.2g IV every 8 hours) achieves 87% resolution rate, comparable to cefotaxime 3

Nosocomial or Healthcare-Associated SBP

This is critical: Nosocomial SBP now has a 35% multidrug-resistant organism (MDRO) rate, requiring broader initial coverage 3

• Meropenem 1g IV every 8 hours PLUS daptomycin 6mg/kg/day for patients with: 1, 3, 6
  • ICU admission
  • Recent hospitalization
  • Recent broad-spectrum antibiotic exposure
  • Sepsis or septic shock
  • High local MDRO prevalence
• This combination is significantly more effective than ceftazidime (86.7% vs 25% resolution) in nosocomial SBP 6

Essential Adjunctive Albumin Therapy

IV albumin is mandatory and non-negotiable for all SBP patients, as it reduces mortality from 29% to 10% and hepatorenal syndrome from 30% to 10% 1, 3, 2

• Dosing regimen: 1.5 g/kg body weight within 6 hours of diagnosis, followed by 1.0 g/kg on day 3 1, 3, 2
• Patients who benefit most: those with renal dysfunction (BUN >30 mg/dL or creatinine >1.0 mg/dL) or severe hepatic decompensation (bilirubin >5 mg/dL) 1
• Albumin prevents progression of acute kidney injury, which is the main predictor of in-hospital mortality in SBP 1

Monitoring Treatment Response

• Repeat paracentesis at 48 hours after initiating antibiotics to assess treatment efficacy 1, 3, 2
• Treatment failure is defined as: PMN count decrease <25% from baseline 1, 3, 2
• If treatment fails, broaden antibiotic coverage and obtain abdominal CT imaging to rule out secondary bacterial peritonitis 1, 2
• Repeat paracentesis may be unnecessary if an organism is isolated, it is susceptible to the antibiotic used, and the patient is improving clinically 1
• Recommended duration of antibiotic therapy is 5-7 days 1, 3

Critical Management Considerations

Hemodynamic Management

• Temporarily hold non-selective beta-blockers (NSBBs) in patients with SBP who develop hypotension (mean arterial pressure <65 mm Hg) or acute kidney injury 1

Avoid These Pitfalls

• Never delay antibiotics waiting for culture results—the PMN count alone is sufficient to initiate therapy 3, 2
• Avoid aminoglycosides (e.g., tobramycin) due to nephrotoxicity in this population 3
• Do not use quinolones in patients already on quinolone prophylaxis, in areas with high quinolone resistance, or in nosocomial SBP 2
• Culture-negative neutrocytic ascites (PMN >250/mm³ with negative culture) should be treated identically to culture-positive SBP 2

Special Scenario: Bacterascites

• Patients with ascites PMN <250/mm³ and positive culture (bacterascites) without signs of infection should NOT receive antibiotics, as most cases self-resolve 1
• Perform repeat diagnostic paracentesis to monitor for progression to SBP 1

Secondary Prophylaxis (After SBP Episode)

All patients surviving an SBP episode require indefinite long-term antibiotic prophylaxis due to 68% one-year recurrence risk without prophylaxis 1

• Norfloxacin 400mg PO daily reduces recurrence from 68% to 20% (withdrawn from US market in 2014) 1
• Oral ciprofloxacin 500mg daily is a reasonable alternative, though direct evidence is lacking 1, 3
• Rifaximin showed lower 6-month recurrence than norfloxacin (4% vs 14%) in limited data 1
• Effectiveness of quinolones is uncertain in patients colonized with MDRO 1

Prognosis

• SBP carries approximately 20% hospital mortality despite infection resolution 2
• Each hour of delay in initiating antibiotics increases in-hospital mortality by 3.3% 2
• Development of acute kidney injury during hospitalization is an independent predictor of 90-day mortality 6
• Ineffective response to first-line treatment is a strong predictor of 90-day survival 6