Peritonitis

Primary or SBP is a common complication of cirrhosis and ascites and should be ruled out in any patients with ascites and fever or other clinical decompensation including encephalopathy, renal failure, and GIB.

    • M. tuberculosis and N. gonorrhea (Fitz-Hugh-Curtis syndrome in women) also occasionally cause primary peritonitis in patients at risk.

Secondary peritonitis is caused by a perforated viscus in the GI or GU tract, or contiguous spread from a visceral infection, usually resulting in an acute surgical abdomen. Pathogens are virtually always mixed.

Peritonitis related to peritoneal dialysis is also an important cause.

Dx:

Dx of secondary peritonitis is made clinically, supplemented by BC (postive 20%-30%) and imaging to evaluate for free air (perforation) or other source of infection.

Labs: Dx of SBP is made by sending paracentesis fluid for culture (directly inoculate BC bottles at bedside), cell count, and differential. BC are often positive. SBP is Dx when ascites fluid has >250 neutrophils.

Tx:

    • Initial broad IV coverage for SBP, culture-negative neutrophilic ascites (CNNA), and symptomatic non-neutrophilic bacterascites (Culture-positive ascites with <250 PMNs) should be narrowed if a causative organism is isolated. Tx duration is 7 days but should be extended to 2 wks if bacteremia is present. Administration of IV albumin on days 1 and 3 of treatment may improve survival. If a repeat paracentesis reveals <250 PMNs and cultures remain negative, treatment may be shortended to 5 days.

      • SBP prophylaxis should be initiated after the first episode of SBP or after variceal bleeding.

    • Secondary peritonitis primarily requires surgical intervention. Empiric antimicrobial therapy must be broad spectrum and tailored for severity and the presumed source while awaiting cultures. Empiric antifungal coverage is not usually indicated. Intra-abdominal abscess formation is a complication of secondary peritonitis that usually requires drainage; antibiotics often must be continued until imaging demonstrates resolution of the fluid collection.

Empiric Therapy for Peritonitis