Spontaneous bacterial peritonitis (SBP)
INTRODUCTION ã…¡ Spontaneous bacterial peritonitis (SBP) is defined as an ascitic fluid infection without an evident intra-abdominal surgically treatable source. The presence of SBP, which almost always occurs in patients with cirrhosis and ascites, is suspected because of signs and symptoms such as fever, abdominal pain, or altered mental status.
The diagnosis is established by a positive ascitic fluid bacterial culture and an ascitic fluid absolute polymorphonuclear leukocyte count ≥ 250 cells/mm3. Patients with SBP should be started on empiric, broad-spectrum antibiotics immediately after peritoneal fluid is obtained. When culture results are available, antibiotic coverage can be tailored to cover the specific organisms identified.
APPROACH TO SBP
DIAGNOSIS ㅡ Consider SBP and perform diagnostic paracentesis if symptoms/signs (abdominal pain, fever, chills), patient is in ER or admitted and worsening renal function or encephalopathy. SBP present if ascites PMN count > 250 cells/ µL (if fluid macroscopically bloody, subtract 1 PMN per 250 RBC/ µL).
MANAGEMENT ã…¡ Avoid large-volume paracenteses during active infection. Intravenous albumin (1 g/kg of body weight) if BUN > 30 mg/dL, creatinine > 1 mg/dL, bilirubin > 4 mg/dL; repeat at day 3 if renal dysfunction persists. Avoid aminoglycosides.
For community-acquired SBP, no history of antibiotic prophylaxis, no history of antibiotics in previous 90 days, no history of infection with MDR organism, prescribe Cefotaxime 2 g IV every 12 hours or Ceftriaxone 2 g every 24 hours or Ceftazidime 2 g every 8 hours. For healthcare associated-SBP or nosocomial SBP (3 days after admission) or history of antibiotics in previous 90 days or history of infection with MDR organism, use broader-spectrum antibiotics such as Vancomycin + Zosyn or Meropenem + Daptomycin.
FOLLOW-UP ã…¡ Continue therapy for 7 days and repeat diagnostic paracentesis at day 2. If ascites PMN count decreases by at least 25% at day 2, IV therapy can be narrowed (if started on broad spectrum AB and organism susceptible) to complete 7 days of therapy. If ascites PMN has not decreased or increases, image the abdomen (at least flat film to detect free air), check culture results and consider broadening antibiotic spectrum.
PREVENTING RECURRENT SBP ã…¡ Should be instituted before patient leaves hospital. Recommended therapy include oral ciprofloxacin 500 mg QD or oral levofloxacin 250 mg QD. TMP-SMX (Septrin DS) 1 double-strength tablet PO QD (Patients who develop quinolone-resistant organisms may also have resistance to TMP-SMX) as alternative therapy. Prophylaxis should be continued until the disappearance of ascites, time of transplantation, or death.
REFERENCES
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Koulaouzidis, A., Bhat, S., Karagiannidis, A., Tan, W.C. and Linaker, B.D. (2007). Spontaneous bacterial peritonitis. Postgraduate Medical Journal, [online] 83(980), pp.379–383. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2600063
Garcia-Tsao, G. and Lim, J. (2009). Management and Treatment of Patients With Cirrhosis and Portal Hypertension: Recommendations From the Department of Veterans Affairs Hepatitis C Resource Center Program and the National Hepatitis C Program. The American Journal of Gastroenterology, 104(7), pp.1802–1829. Available at: https://pubmed.ncbi.nlm.nih.gov/19455106
