What is the treatment for spontaneous bacterial peritonitis in a patient with cirrhosis of the liver and ascites?

Treatment of Spontaneous Bacterial Peritonitis in Cirrhotic Patients with Ascites

Start a third-generation cephalosporin immediately upon diagnosis—specifically cefotaxime 2g IV every 6-8 hours or ceftriaxone 1-2g IV every 12-24 hours for 5 days—combined with intravenous albumin 1.5 g/kg at diagnosis and 1.0 g/kg on day 3. 1, 2

Immediate Empirical Antibiotic Therapy

Do not wait for culture results to initiate treatment. The diagnosis is established by ascitic fluid polymorphonuclear (PMN) count >250/mm³, and antibiotics must be started immediately as each hour of delay increases mortality by 10% in septic shock. 1, 2

First-Line Antibiotic Selection

• Third-generation cephalosporins are the gold standard because the most common causative organisms are gram-negative aerobic bacteria, particularly E. coli and Klebsiella pneumoniae. 1

• Cefotaxime 2g IV every 6-8 hours achieves 77-98% resolution rates and is the most extensively studied regimen. 1, 2

• Ceftriaxone 1-2g IV every 12-24 hours is equally effective and may be more convenient for dosing. 1, 3

• Treatment duration is 5 days, which is as effective as 10-day courses. 1, 2

Alternative Antibiotic Options

• Amoxicillin-clavulanic acid (1g/0.2g IV every 8 hours initially, then 0.5g/0.125g PO every 8 hours) achieves similar 87% resolution rates to cefotaxime. 1

• Oral ofloxacin 400mg twice daily can be used in uncomplicated SBP only—meaning patients without renal failure, hepatic encephalopathy, gastrointestinal bleeding, ileus, or shock. 1, 2

Critical Antibiotic Restrictions

Avoid quinolones (ciprofloxacin, ofloxacin) in three specific situations: 1, 2

• Patients already on quinolone prophylaxis for SBP
• Areas with high prevalence of quinolone-resistant bacteria
• Nosocomial SBP (infection acquired >48 hours after admission)

For nosocomial SBP, use broader-spectrum coverage with meropenem 1g IV every 8 hours plus daptomycin 6mg/kg/day due to high rates of multidrug-resistant organisms and ESBL-producing bacteria. 3, 4

Mandatory Albumin Administration

Albumin is not optional—it provides mortality benefit independent of antibiotics. 1, 2, 3

• Give 1.5 g/kg body weight within 6 hours of diagnosis, followed by 1.0 g/kg on day 3. 1, 2

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

• Albumin is particularly critical in patients with baseline serum bilirubin ≥4 mg/dL or serum creatinine ≥1 mg/dL. 1

• The benefit of albumin is unclear in patients with bilirubin <4 mg/dL and creatinine <1 mg/dL, as their risk of hepatorenal syndrome is already low (7% without albumin vs 0% with albumin). 1

Monitoring Treatment Response

Perform repeat paracentesis at 48 hours to assess treatment efficacy. 1, 2, 3

• Treatment success is defined as ascitic PMN count decreasing to <25% of pre-treatment value. 1, 2, 3

• Treatment failure is suspected if PMN count fails to decrease by at least 25%, or if clinical signs and symptoms worsen. 1, 2

Management of Treatment Failure

If the patient fails to respond after 48 hours: 1

1. Rule out secondary bacterial peritonitis with abdominal CT imaging, especially if multiple organisms are present, ascitic protein >1 g/dL, glucose <50 mg/dL, or LDH above normal serum levels. 1, 3, 5

2. Change antibiotics based on culture sensitivities if available, or escalate empirically to broader-spectrum agents such as piperacillin-tazobactam or carbapenems. 1, 3

3. For patients on norfloxacin prophylaxis who develop SBP, use cefotaxime or amoxicillin-clavulanic acid as these remain effective. 1, 2

Common Pitfalls to Avoid

• Never delay antibiotics waiting for culture results—the PMN count alone is sufficient to diagnose and treat. 1, 2

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

• Never forget albumin administration—it significantly reduces mortality and hepatorenal syndrome. 1, 3

• Never assume SBP in patients with surgical drains or recent abdominal procedures—always rule out secondary peritonitis first with CT imaging. 3, 5

• Culture-negative neutrocytic ascites (PMN >250/mm³ with negative culture) should be treated identically to culture-positive SBP, as both have similar morbidity and mortality. 2, 5

Prognosis and Follow-Up

• SBP carries approximately 20% hospital mortality despite infection resolution. 1, 2

• All patients surviving SBP require indefinite secondary prophylaxis with norfloxacin 400mg PO daily (or ciprofloxacin 500mg daily) until ascites resolves or liver transplantation occurs. 3

• Liver transplant evaluation should be undertaken for all patients who develop SBP, barring contraindications. 6