When should antibiotics be used in patients with cirrhosis (liver scarring) of the liver and ascites (fluid accumulation in the abdomen)?

Antibiotic Use in Patients with Cirrhosis and Ascites

Antibiotics should be used in patients with cirrhosis and ascites when spontaneous bacterial peritonitis (SBP) is diagnosed or suspected, when gastrointestinal bleeding occurs, and as prophylaxis in high-risk patients or those with prior SBP episodes. 1

Diagnostic Criteria for SBP

• SBP is diagnosed when ascitic fluid polymorphonuclear (PMN) count is >250 cells/mm³ 1, 2
• Diagnostic paracentesis must be performed:
  • In all patients with new-onset ascites 1
  • In all cirrhotic patients with ascites on hospital admission 1
  • In patients with GI bleeding, shock, fever, signs of systemic inflammation, gastrointestinal symptoms, hepatic encephalopathy, or worsening liver/renal function 1

Treatment of Confirmed or Suspected SBP

Immediate Empirical Therapy

• Start antibiotics immediately when:
  • Ascitic fluid PMN count ≥250 cells/mm³ 1
  • PMN count <250 cells/mm³ but signs/symptoms of infection (fever >37.8°C, abdominal pain/tenderness) 1, 2

First-Line Treatment Options

• Third-generation cephalosporins:
  • Cefotaxime 2g IV every 6-8 hours for 5-7 days 1, 2
  • Ceftriaxone 1g IV every 12-24 hours for 5-7 days 2

Treatment Considerations

• Consider local resistance patterns when selecting antibiotics 1
• Differentiate between community-acquired and healthcare-associated infections when choosing empirical therapy 1, 2
• Perform ascitic fluid culture with bedside inoculation of blood culture bottles 1
• Consider IV albumin (1.5 g/kg at diagnosis and 1 g/kg on day 3) in high-risk patients (serum bilirubin ≥4 mg/dL or creatinine ≥1 mg/dL) to reduce risk of hepatorenal syndrome 2

Monitoring Treatment Response

• Consider follow-up paracentesis after 48 hours of treatment to check efficacy 1
• If no improvement after 48 hours:
  • Rule out secondary bacterial peritonitis
  • Adjust antibiotics based on culture results
  • Consider broader spectrum antibiotics 2

Prophylactic Antibiotic Use

Secondary Prophylaxis (After SBP Episode)

• Patients who have recovered from SBP should receive:
  • Norfloxacin 400 mg once daily, OR
  • Ciprofloxacin 500 mg once daily, OR
  • Co-trimoxazole 800 mg sulfamethoxazole/160 mg trimethoprim daily 1, 3

Primary Prophylaxis (No Prior SBP)

• Offer to high-risk patients with:
  • Ascitic protein count <1.5 g/dL 1
  • Gastrointestinal bleeding (prophylaxis during bleeding episode) 1

Prophylactic Antibiotic Options

• For GI bleeding: Cefotaxime (widely studied but choose based on local resistance patterns) 1
• For high-risk patients: Norfloxacin is most widely used, but trimethoprim-sulfamethoxazole and rifaximin are alternatives 3
• Weekly ciprofloxacin may be an alternative to daily norfloxacin 3

Special Considerations

• Secondary bacterial peritonitis: Suspect if multiple organisms on culture, high ascitic PMN count (>1000/mm³), or inadequate response to therapy. Requires surgical intervention and anaerobic antibiotic coverage 1, 2

• Antibiotic resistance concerns: Quinolone resistance is increasing, especially in patients previously exposed to quinolones 2

• Rifaximin: May be more effective than norfloxacin for secondary prophylaxis with fewer adverse events 3

Pitfalls to Avoid

• Delayed paracentesis: Perform diagnostic paracentesis without delay when SBP is suspected 1
• Inadequate empiric coverage: Consider local resistance patterns and differentiate between community-acquired and nosocomial infections 1, 2
• Missing secondary peritonitis: Always consider secondary peritonitis when response to therapy is inadequate 1, 2
• Overlooking albumin administration: High-risk patients with SBP should receive IV albumin to prevent hepatorenal syndrome 2
• Inappropriate prophylaxis: Limit selective intestinal decontamination to high-risk patients to avoid selecting resistant organisms 1