What is the management of Spontaneous Bacterial Peritonitis (SBP) in patients with a history of liver disease, particularly those with cirrhosis and ascites?

Management of Spontaneous Bacterial Peritonitis (SBP)

Immediately initiate empiric antibiotic therapy with a third-generation cephalosporin (cefotaxime 2g IV every 8 hours or ceftriaxone 1-2g IV every 12-24 hours) within one hour of diagnosis, and administer IV albumin (1.5 g/kg at diagnosis, followed by 1 g/kg on day 3) to patients with baseline bilirubin ≥68 µmol/L (4 mg/dL) or creatinine ≥88 µmol/L (1 mg/dL) to reduce mortality and prevent hepatorenal syndrome. 1, 2

Diagnostic Confirmation

• Perform diagnostic paracentesis immediately in all cirrhotic patients with ascites at hospital admission, and in any patient presenting with fever, abdominal pain, encephalopathy, renal impairment, gastrointestinal bleeding, shock, or unexplained clinical deterioration. 1

• Diagnose SBP when ascitic fluid neutrophil count is ≥250 cells/mm³ by microscopy, regardless of culture results. 1

• Inoculate ascitic fluid into blood culture bottles at the bedside to maximize culture yield (though only 40-60% of cases will be culture-positive). 1

• Obtain blood cultures before starting antibiotics in all patients with suspected SBP. 1

Empiric Antibiotic Therapy

First-line treatment:

• Cefotaxime 2g IV every 8 hours for 5 days is the gold standard, achieving 77-98% infection resolution rates and covering 95% of causative organisms (predominantly E. coli, Streptococcus species, and Enterococcus). 1, 2

• Ceftriaxone 1-2g IV every 12-24 hours is equally effective as an alternative third-generation cephalosporin. 1, 3

Alternative regimens:

• Amoxicillin/clavulanic acid (given IV initially, then orally) achieves similar resolution rates to cefotaxime but has only been studied in one small trial. 1

• Oral ofloxacin 400mg every 12 hours is acceptable only for uncomplicated SBP in patients without renal failure, hepatic encephalopathy, gastrointestinal bleeding, ileus, or shock. 1, 3

• Avoid quinolones in patients already on quinolone prophylaxis, in areas with high quinolone resistance, or in nosocomial SBP. 1, 4

• Never use aminoglycosides due to nephrotoxicity risk in cirrhotic patients. 1, 3

Critical Adjunctive Therapy: Intravenous Albumin

Albumin administration significantly reduces mortality and hepatorenal syndrome:

• Give 1.5 g/kg IV albumin at diagnosis (within 6 hours), followed by 1 g/kg on day 3. 1, 2

• This regimen reduces hepatorenal syndrome incidence from 30% to 10% and mortality from 29% to 10%. 1, 2, 3

• Albumin is particularly critical in patients with baseline bilirubin ≥68 µmol/L (4 mg/dL) or creatinine ≥88 µmol/L (1 mg/dL). 1

• In patients with lower bilirubin (<68 µmol/L) and creatinine (<88 µmol/L), the benefit is less clear, as hepatorenal syndrome risk is already low (7% without albumin vs 0% with albumin). 1

• Albumin improves circulatory function in ways that crystalloids and artificial colloids (like hydroxyethyl starch) cannot replicate. 1

Monitoring Treatment Response

• Perform repeat paracentesis at 48 hours after initiating treatment to assess response. 1, 2, 3

• Treatment success is defined as ascitic neutrophil count decreasing to <25% of pre-treatment value or <250 cells/mm³. 1, 2

• If neutrophil count fails to decrease appropriately or clinical signs worsen, suspect antibiotic failure due to resistant organisms or secondary bacterial peritonitis. 1

• When treatment fails, change antibiotics based on culture sensitivities or switch to broader empiric coverage (consider piperacillin-tazobactam for nosocomial cases). 1, 4

• Exclude secondary bacterial peritonitis with CT imaging if there is treatment failure, as this requires surgical intervention. 1

Treatment Duration

• 5 days of antibiotic therapy is as effective as 10 days for most cases of SBP. 1, 2

• For patients with septic shock, treat for 7-10 days and narrow coverage once pathogen identification and sensitivities are available. 2

Secondary Prophylaxis (After SBP Episode)

All patients who survive an episode of SBP require indefinite secondary prophylaxis:

• The recurrence rate without prophylaxis is 68% at one year compared to 20% with prophylaxis. 1, 5

• Norfloxacin 400mg PO once daily is the standard prophylactic regimen, reducing recurrence from 68% to 20% and gram-negative SBP from 60% to 3%. 1, 5

• Ciprofloxacin 500mg PO once daily is an acceptable alternative. 1, 5

• Continue prophylaxis until ascites resolves or liver transplantation occurs. 5

• Monitor for quinolone resistance, particularly in areas with high fluoroquinolone use, as long-term prophylaxis may shift infections toward gram-positive organisms (79% vs 67% gram-negative in non-prophylaxis patients). 1, 5

Liver Transplantation Evaluation

• All patients with SBP should be evaluated for liver transplantation, as one-year survival after SBP is only 30-50%, falling to 25-30% at two years. 1, 4

• Despite 90% infection resolution rates with antibiotics, hospital mortality remains 20-30% due to underlying liver disease severity. 1, 2, 6

Critical Pitfalls to Avoid

• Do not delay antibiotics waiting for culture results—empiric therapy must start immediately upon diagnosis. 1, 2

• Do not use aminoglycosides as they are nephrotoxic in cirrhotic patients. 1, 3

• Do not use quinolones in patients already on quinolone prophylaxis or in nosocomial SBP due to resistance concerns. 1, 4

• Do not forget albumin in patients with elevated bilirubin or creatinine, as this is the only intervention proven to reduce mortality beyond antibiotics alone. 1, 2

• Do not assume treatment success without repeat paracentesis at 48 hours, as clinical improvement alone may be misleading. 1, 2