Peritonitis – secondary

Infections that arise from microbes in the alimentary tract due to perforation of a hollow viscus causing contamination of the otherwise sterile peritoneal cavity. The primary therapy is surgical correction of the perforated viscus.

Usual Pathogens
Enterobacteriaceae
Anaerobes
Enterococcus spp. (routine coverage typically not required)

MILD to MODERATE

Severity criteria (one or more):

  • Steady and severe pain (RUQ or epigastrium)
  • Fever
  • Leukocytosis

Additional Points:

  • Prior antibiotic use in the last 3 months is a significant consideration in empiric therapy selection. Use of an agent from a different class of antibiotic is highly recommended.
  • Shorter durations of therapy should be encouraged when patients exhibit significant clinical improvement after surgery.
  • Obtain blood cultures.

Recommended Empiric Therapy (4 – 7 days)

Cefazolin 1 g IV q8h +
Metronidazole 500 mg IV/PO q8h

Severe penicillin or cephalosporin allergy (e.g. anaphylaxis, angioedemia)

Ciprofloxacin 400 mg IV / 500 mg PO q12h +
Metronidazole 500 mg IV/PO q8h

Severe or High Risk

Severity Criteria
Septic presentation (includes the following):

  • Systemic inflammatory response syndrome (SIRS): hypothermia or fever; tachycardia; tachypnea or hypocapnia (arterial CO2 less than 32 mm Hg); and leukopenia or leukocytosis.
  • Evidence of organ dysfunction, hypotension (low blood pressure), or hypoperfusion to 1 or more organs.
  • Arterial hypotension or hypoperfusion is responsive to adequate fluid resuscitation. If unresponsive see empiric therapy for SEPTIC SHOCK below.

High Risk criteria (one or more):

  • Healthcare-associated infection.

Those requiring enterococcal coverage such as:

  • Antimicrobial exposure in the last 90 days to cephalosporins and other broad-spectrum regimens selecting for enterococci.
  • With valvular heart disease or intravascular prosthetic devices.
  • Severe immunosuppression (e.g. solid organ transplant, or high-dose steroids).

Additional Points:

  • Prior antibiotic use in the last 3 months is a significant consideration in empiric therapy selection. Use of an agent from a different class of antibiotic is highly recommended.
  • Blood cultures recommended (high risk of bacteremia).

Usual Pathogens
Enterobacteriaceae
Anaerobes
Enterococcus spp.

Recommended Empiric Therapy (4 – 7 days)

Duration should be guided by intraoperative findings and clinical response and should be no more than 7 days in most cases.

Piperacillin-tazobactam 3.375 g IV q6h

Severe penicillin or cephalosporin allergy (e.g. anaphylaxis, angioedemia)

Ciprofloxacin 400 mg IV q12h + Metronidazole 500 mg IV q8h + Vancomycin 15 mg/kg (round to nearest 250 mg) IV q12h.
Adjust vancomycin interval based on GFR.

Septic Shock

Criteria (includes all of the following):

  • Systemic inflammatory response syndrome (SIRS) which includes hypothermia or fever; tachycardia; tachypnea or hypocapnia (arterial CO2 less than 32 mm Hg); and leukopenia or leukocytosis.
  • Evidence of organ dysfunction, hypotension (low blood pressure), or hypoperfusion to 1 or more organs.
  • Arterial hypotension or hypoperfusion (despite adequate fluid resuscitation) resulting in the need for vasopressors.

Additional Points:

  • Implement antibiotics immediately. Broad-spectrum agents should be infused first.
  • Consult intensive care.

Recommended Empiric Therapy (4 – 7 days)

Duration should be guided by intra-operative findings and clinical response and should be no more than 7 days in most cases.

Imipenem 500 mg IV q6h + Vancomycin 20 mg/kg (round to nearest 250 mg) x 1 dose, then 15 mg/kg (round to nearest 250 mg) IV q12h.
Adjust vancomycin interval based on GFR.

Severe pen-allergy or cephalosporin allergy (e.g. anaphylaxis, angioedemia):

Ciprofloxacin 400 mg IV q12h + Gentamicin 2 mg/kg IV x STAT (further dosing to be reassessed by the attending intensivist) + Metronidazole 500 mg IV q8h + Vancomycin 20 mg/kg (round to nearest 250 mg) x 1 dose, then 15 mg/kg (round to nearest 250 mg) IV q12h.
Adjust interval based on GFR.

Category: Intraabdominal Infections

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