What is the initial management of spontaneous bacterial peritonitis?

Management of Spontaneous Bacterial Peritonitis

Initiate third-generation cephalosporin antibiotics immediately upon diagnosis combined with intravenous albumin for patients meeting high-risk criteria, without waiting for culture results. 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 for cell count and culture before starting antibiotics 1
• Diagnosis is confirmed when ascitic fluid polymorphonuclear (PMN) count exceeds 250 cells/mm³, regardless of culture results 1, 2
• Inoculate at least 10 mL of ascitic fluid into blood culture bottles at bedside to increase culture sensitivity to >90% 2
• Obtain blood cultures simultaneously before antibiotic initiation 1

First-Line Antibiotic Therapy

Start empirical antibiotics immediately—do not wait for culture results. 1

Community-Acquired SBP

• Cefotaxime 2 g IV every 8 hours for 5 days is the first-line treatment with 77-98% infection resolution rates 1, 2, 3
• Alternative regimens include:
  • Cefotaxime 2 g IV every 12 hours (equally effective as every 8 hours dosing) 1, 3
  • Amoxicillin-clavulanic acid 1/0.2 g IV every 8 hours followed by 0.5/0.125 g PO every 8 hours 1
  • Oral ofloxacin 400 mg twice daily for uncomplicated SBP (without renal failure, hepatic encephalopathy, GI bleeding, ileus, or shock) 1

Nosocomial SBP

• Avoid quinolones and third-generation cephalosporins in nosocomial SBP due to high rates of resistant organisms 1
• Meropenem 1 g IV every 8 hours plus daptomycin 6 mg/kg/day is significantly more effective than ceftazidime (86.7% vs. 25% resolution rate) 4

Special Circumstances

• For patients on quinolone prophylaxis: Use cefotaxime or amoxicillin-clavulanic acid, never quinolones 1
• Avoid aminoglycosides due to nephrotoxicity risk in cirrhotic patients 1, 5

Critical Adjunctive Therapy: Intravenous Albumin

Albumin administration is essential and significantly reduces mortality and hepatorenal syndrome. 1, 2, 6

Dosing Protocol

• 1.5 g/kg IV within 6 hours of diagnosis 1, 2, 6
• 1.0 g/kg IV on day 3 1, 2, 6

Evidence for Albumin

• Reduces mortality from 29% to 10% 1, 6
• Decreases type 1 hepatorenal syndrome from 30% to 10% 1, 6
• Most beneficial in patients with baseline serum bilirubin ≥4 mg/dL (68 μmol/L) or serum creatinine ≥1 mg/dL (88 μmol/L) 1

Monitoring Treatment Response

• Perform repeat paracentesis at 48 hours to assess treatment efficacy 1, 2
• Treatment success is defined as ascitic PMN count decreasing to <25% of pre-treatment value 1
• Clinical improvement should accompany laboratory response 2

Treatment Failure Criteria

• Failure of ascitic neutrophil count to decrease by at least 25% of pre-treatment value 1, 7
• Worsening clinical signs and symptoms 1, 7
• Persistent or increasing ascitic fluid neutrophil count 1

Management of Treatment Failure

If treatment fails after 48 hours, suspect resistant bacteria or secondary bacterial peritonitis. 1, 7

Approach to Treatment Failure

• Obtain CT imaging to exclude secondary bacterial peritonitis (perforated viscus, intra-abdominal abscess) 1
• Suspect secondary peritonitis if: multiple organisms on culture, very high ascitic neutrophil count, high ascitic protein concentration, or localized abdominal symptoms 1
• Change antibiotics based on culture sensitivities or escalate empirically to broader-spectrum agents 1
• Consider surgical consultation if secondary peritonitis is suspected 1, 7

Treatment Duration

• 5 days of antibiotic therapy is as effective as 10 days for most cases of SBP 1, 2, 3
• Continue antibiotics for minimum 48-72 hours after defervescence or evidence of bacterial eradication 8
• For septic shock, treat for 7-10 days 6

Critical Pitfalls to Avoid

• Never delay antibiotics waiting for culture results—each hour of delay increases mortality by 3.3% in septic shock 2, 6
• Do not use quinolones in patients already on quinolone prophylaxis, in areas with high quinolone resistance, or in nosocomial SBP 1
• Avoid nephrotoxic agents (aminoglycosides) in cirrhotic patients 1, 5
• Do not admix cefotaxime with aminoglycosides—if both are needed, administer separately 8
• Culture-negative neutrocytic ascites (PMN >250/mm³ with negative culture) should be treated identically to culture-positive SBP 2

Prognosis

• SBP resolves with appropriate antibiotic therapy in approximately 90% of patients 1
• Hospital mortality remains 20-30% despite infection resolution, primarily due to complications like renal failure, hepatic encephalopathy, and underlying liver disease severity 1, 6
• Albumin therapy significantly improves survival outcomes 1, 2, 6