Spontaneous Bacterial Peritonitis

Spontaneous bacterial peritonitis (SBP) is infection of ascitic fluid without an intra abdominal surgical source, in cirrhosis.

• Occurs in 10 to 30% of hospitalised patients with cirrhosis and ascites. Mortality 20 to 30% with treatment.
• Mechanism: bacterial translocation from the gut, impaired reticuloendothelial function, low ascitic protein and complement.
• Organisms: Escherichia coli, Klebsiella, Streptococcus pneumoniae; increasing multidrug resistant Gram negatives and Enterococcus in nosocomial infection.
• Risk factors: low ascitic protein (under 1.5 g/dL), prior SBP, variceal bleeding, advanced Child-Pugh class, PPI use.
• Complications: hepatorenal syndrome (30%), sepsis, encephalopathy, recurrence (70% in 1 year without prophylaxis).

• Fever, abdominal pain and tenderness, vomiting, diarrhoea, ileus.
• Worsening ascites, encephalopathy, jaundice, hypotension, renal failure.
• May be asymptomatic or subtle. Any hospitalised cirrhotic patient with ascites needs a paracentesis.
• Differential: secondary bacterial peritonitis (perforation, abscess), pancreatitis, malignant ascites.

• Diagnostic paracentesis before antibiotics: ascitic polymorphonuclear count of 250 cells/mm3 or more.
• Inoculate ascitic fluid into blood culture bottles at the bedside (sensitivity over 80%); blood cultures.
• Variants: culture negative neutrocytic ascites (PMN 250 or more, negative culture), monomicrobial non neutrocytic bacterascites (PMN under 250, positive culture; repeat tap).
• Suspect secondary peritonitis if multiple organisms, ascitic protein over 1 g/dL, glucose under 50 mg/dL, LDH over upper normal for serum, failure to respond in 48 hours; CT abdomen.
• Check creatinine, white count, bilirubin, INR.

• Empirical antibiotics immediately: ceftriaxone 2 g IV daily for 5 to 7 days (community acquired); piperacillin tazobactam 4.5 g IV every 6 hours or meropenem 1 g every 8 hours for nosocomial or healthcare associated infection and prior resistant organisms.
• Albumin 1.5 g/kg on day 1 and 1 g/kg on day 3, reduces renal failure and mortality, especially with creatinine over 1 mg/dL, bilirubin over 4 mg/dL or urea over 30 mg/dL.
• Repeat paracentesis at 48 hours: PMN fall of over 25% indicates response.
• Stop diuretics, beta blockers and nephrotoxins during the episode. Treat precipitants.
• Secondary prophylaxis after the first episode: norfloxacin 400 mg daily (ciprofloxacin 500 mg daily or trimethoprim sulfamethoxazole 160/800 mg daily alternatives), lifelong until transplant or resolution of ascites.
• Primary prophylaxis: ascitic protein under 1.5 g/dL with renal impairment (creatinine 1.2 mg/dL or more, urea 25 mg/dL or more, sodium 130 mmol/L or less) or liver failure (Child-Pugh 9 or more with bilirubin 3 mg/dL or more); GI bleeding: ceftriaxone 1 g daily for up to 7 days.
• Review PPIs, and refer for liver transplantation.