What is the management plan for a patient with Spontaneous Bacterial Peritonitis (SBP) and malignant ascites?

Management of Spontaneous Bacterial Peritonitis (SBP) in Patients with Malignant Ascites

Third-generation cephalosporins are the first-line treatment for SBP in patients with malignant ascites, with IV cefotaxime (2g every 8-12 hours) being the most effective empirical antibiotic therapy that should be initiated immediately after diagnosis.1

Diagnostic Approach

• Diagnostic paracentesis must be performed in all patients with ascites who present with:

  • Signs or symptoms of infection (fever, abdominal pain)
  • Worsening liver or renal function
  • Hepatic encephalopathy
  • Gastrointestinal bleeding
  • Even in asymptomatic patients being admitted to the hospital 1

• SBP is diagnosed when ascitic fluid polymorphonuclear (PMN) leukocyte count is >250/mm³ 1

• Ascitic fluid should be cultured at bedside in aerobic and anaerobic blood culture bottles before starting antibiotics to increase culture yield to >90% 1

• Blood cultures should also be obtained simultaneously to increase the possibility of isolating the causative organism 1

Empirical Antibiotic Treatment

• Start empirical antibiotics immediately after diagnosis without waiting for culture results 1

• First-line antibiotic options:

  • Cefotaxime: 2g IV every 8-12 hours for 5-7 days (most extensively studied with 77-98% infection resolution) 1
  • Ceftriaxone: 1-2g IV every 24 hours (alternative third-generation cephalosporin) 2

• Alternative antibiotic options:

  • Amoxicillin/clavulanic acid: 1/0.2g IV every 8 hours, followed by oral step-down therapy 1
  • Ciprofloxacin: 200mg IV every 12 hours or switch therapy (IV for 2 days followed by oral for 5 days) 1

• For nosocomial SBP (hospital-acquired) or healthcare-associated infections:

  • Consider broader spectrum antibiotics like meropenem plus daptomycin due to higher rates of multidrug-resistant organisms (MDROs) 1, 3
  • Avoid quinolones in patients already on quinolone prophylaxis or in areas with high quinolone resistance 1

Adjunctive Therapy with Albumin

• Intravenous albumin should be administered alongside antibiotics to reduce the risk of renal impairment and mortality 1, 4

• Recommended dosing: 1.5 g/kg body weight at diagnosis, followed by 1 g/kg on day 3 1

• This intervention has been shown to decrease the incidence of type 1 hepatorenal syndrome from 30% to 10% and reduce mortality from 29% to 10% 1

Monitoring Treatment Response

• Perform a second paracentesis after 48 hours of treatment to assess response 1

• Treatment success is indicated by:

  • Decrease in ascitic fluid neutrophil count to <250/mm³
  • Sterile cultures (if positive at diagnosis)
  • Clinical improvement 1

• If neutrophil count fails to decrease by at least 25% of pre-treatment value after 48 hours, suspect treatment failure 1

Management of Treatment Failure

• Treatment failure may be due to:

  • Antibiotic-resistant bacteria
  • Secondary bacterial peritonitis 1

• If treatment failure is suspected:

  • Rule out secondary peritonitis (consider CT scan) 1
  • Modify antibiotics based on culture and sensitivity results
  • If cultures are negative, switch to broader spectrum antibiotics 1

Special Considerations for Malignant Ascites

• Patients with malignant ascites may have different bacterial flora and potentially more resistant organisms 1, 5

• Diagnostic paracentesis is essential to differentiate between malignant ascites and SBP, as both can coexist 1

• Consider broader spectrum antibiotics in patients with malignant ascites who have had recent hospitalizations or antibiotic exposure 1, 3

Prophylaxis After SBP Episode

• Long-term antibiotic prophylaxis is recommended after an episode of SBP until liver transplantation or resolution of ascites 2

• Norfloxacin 400 mg daily is the most studied regimen, reducing recurrence from 68% to 20% 2

• In patients with malignant ascites, prophylaxis should be considered on an individual basis depending on prognosis and risk factors 5

Pitfalls and Caveats

• Avoid nephrotoxic antibiotics (e.g., aminoglycosides) as empirical therapy in patients with SBP 1

• Be aware of the increasing prevalence of multidrug-resistant organisms, particularly in nosocomial and healthcare-associated SBP 1, 3

• Do not delay antibiotic administration while waiting for culture results 1

• Routine correction of coagulation abnormalities before paracentesis is not recommended 4

• Consider discontinuing acid-suppressive medications and beta-blockers in patients with SBP, as they may increase the risk of infection 5