Intra-abdominal Abscess
PATHOGENS
- If source of abscess identified, location (e.g., site of perforation - stomach, duodenum, jejunum, ileum, appendix or colon) defines likely flora.
- Enterobacteriaceae and other Gram-negative bacilli
- Anaerobes including Bacteroides spp., Fusobacterium spp., Clostridium spp., Actinomyces spp., etc.
- Enterococci
- Candida species
- Occasionally, Gram-positives including Staphylococcus aureus and Streptococci spp.
- Health-care associated flora more likely when infections are complications of prior intraabdominal operations or procedures.
CLINICAL
- Broad range of presenting complaints:
- Patients may only present with malaise/anorexia or weight loss.
- Others present acutely ill in septic shock with localized pain or an acute abdomen.
- Non visceral abscesses develop after gastrointestinal perforation from local disease (diverticulitis, etc.), trauma or surgical intervention.
- Abscess known to occur in up to 40% of cases of acute complicated diverticulitis.
- Subsequent secondary peritonitis then becomes walled off by inflammatory adhesions, loops of intestine, mesentery or omentum, and other abdominal viscera.
- Intraabdominal abscess also may develop after primary peritonitis (spontaneous bacterial peritonitis).
- History: fever, pain, nausea, vomiting, anorexia, abdominal pain.
- PE: local tenderness, possibly a palpable mass; if postoperative, assessment for abscess confounded by analgesics, ileus and incisional pain; over half presenting within 10 days of initial operation.
- Lab:
- Elevated WBC common
- Derangement of liver enzymes, elevated alkaline phosphatase or hypergammaglobulinemia depending on duration and location of the abscess (e.g., liver, gallbladder, etc.)
- Blood cultures positive ~25% depending on site and severity
- Direct aspiration yielding positive Gram stain/culture
DIAGNOSIS
- Imaging:
- CT most helpful.
- US and MRI used occasionally.
- MRI not used for drainage guidance.
- CT- or US-guided percutaneous or surgical drainage should be considered in all cases for diagnostic confirmation, microbiological evaluation, and therapy.
- Where feasible, percutaneous drainage of well-localized fluid collections is preferable to surgical drainage for diagnostic and therapeutic purposes.
- Complication rate of percutaenous abscess drainage is low (~2.5%), but should be taken into account when managing patients.
TREATMENT
Primary therapy: abscess drainage
- CT or US-guided percutaneous needle aspiration with subsequent catheter drainage is considered by many as the first line therapy; if drainage is inadequate surgery may be required.
- Surgery used primarily after percutaneous therapy has failed, after percutaneous therapy has stabilized the condition in preparation for primary surgical therapy, or when concurrent surgical source control needed.
- Infected pancreatic necrosis not well suited to percutaneous therapy because of cellular debris.
- If an abscess unrelated to a surgical procedure or other obvious source is encountered, must consider the possibility of an underlying necrotic cancer.
- Antimicrobial therapy alone (without drainage or a surgical procedure) should be reserved for highly-selected patients with a relatively small (< 3 cm diameter), well-circumscribed area of infection and minimal physiological derangement, provided close monitoring and follow-up can be arranged.
Adjunctive antibiotic treatment
- Empiric coverage (microbiologic source of infection unknown) should include coverage of Enterobacteriaceae, enteric Streptococci, and anaerobes.
- Empirical coverage of Enterococci should be considered in hospital-acquired and healthcare-associated infections.
- Empiric coverage may be broadened or cautiously narrowed on the basis of the abscess and blood culture results.
- Isolation of Candida may not require treatment if patient is improving without antifungal therapy.
- May modify antibiotic treatment once cultures have returned.
- Mild-moderate infection
- Preferred:
- Ticarcillin/clavulanate 3.1g IV q6h (no longer available in U.S.)
- Ertapenem 1g IV q24h
- Moxifloxacin 400 mg IV/PO q24h
- Alternatives:
Combination therapy:- One of the following:
- Cefazolin 2g IV q 8h
- Ceftriaxone 2g IV q24h
- Cefotaxime 2g IV q8h
- Cefuroxime 1.5g IV q8h
- Ciprofloxacin 400mg IV q12h or 500mg PO twice daily
- Levofloxacin 500mg IV/PO once daily
- PLUS metronidazole 500mg IV/PO q6-8h
- One of the following:
- Additional monotherapy option: tigecycline 100 mg IV x 1, then 50 mg IV q12h. Useful for patients with allergy issues or multitude-resistant organisms, see selected drug comments below.
- Preferred:
- Severe and/or nosocomial infections
- Preferred:
- Piperacillin/tazobactam 3.375g IV q6h or 4.5g IV q8h
- Imipenem/cilastatin 0.5g IV q6h
- Meropenem 1.0g IV q8h
- Doripenem 500 mg IV q8h
- Alternatives: combination therapy
- One of the following:
- Cefepime 1-2 g IV q12h
- Ceftazidime 2g IV q8h
- Ciprofloxacin 400 mg IV q12h
- Levofloxacin 500 mg IV q24h
- PLUS metronidazole 500 mg IV q8h
- One of the following:
- Preferred:
- Duration: after adequate drainage, at least 4-7 days of antibiotic coverage is indicated, with duration in part based on resolution of fever and leukocytosis, severity of infection, and additional indicators of clinical response.
- Duration of therapy has not been subjected to rigorous study.
- If the underlying surgical problem or source has been difficult to control, a longer course of antibiotics maybe appropriate.
- Duration of antibiotic therapy for an inadequately drained abscess with residual fluid may require prolonged therapy with follow-up imaging to ensure resolution, but sufficient data are lacking to fully support this approach.
Selected Drug Comments
Drug | Recommendation |
Increased rates of resistance makes this a poor choice nowadays for empiric therapy. Historically good coverage of Gram-positive, Gram-negative, and anaerobic pathogens - lacks Pseudomonas aeruginosa and has diminished Enterobacteriaceae susceptibilities but good Enterococcus species coverage. | |
Excellent broad spectrum coverage including Gram-positive coverage, Gram-negative coverage (including Pseudomonas aeruginosa and beta-lactamase producing pathogens) and anaerobic coverage. | |
Good broad spectrum coverage including ESBL Gram-negatives and anaerobes, but doesn’t provide coverage for Pseudomonas aeruginosa. Also no enterococcal coverage unlike imipenem. | |
Excellent coverage of Gram-negative and Gram-positive pathogens; use in combination with anaerobic agent (plus/minus an agent covering Enterococcus species) for empiric therapy. | |
Excellent broad spectrum coverage including Gram-negatives and most anaerobes, but does not provide coverage for P. aeruginosa. Due to increasing Bacteroides resistance would only use for mild infections. | |
Historically excellent broad spectrum coverage including gram-positive coverage, gram-negative coverage (including Pseudomonas aeruginosa and B-lactamase-producing pathogens) and anaerobic coverage. Due to rising rates of Gram negative resistance, would only use for mild-moderate infections empirically. This agent is no longer available in the U.S. marketplace. | |
Glycyltetracycline with very broad coverage (Gram-positive including MRSA and VRE, Gram-negatives including Acinetobacter spp. but not P. aeruginosa or Proteus sp). Good choice in patients with high-grade beta-lactam allergy. Recent pooled analysis of clinical trials revealed an increased mortality risk compared with other antibiotics used to treat a variety of infections, including IAIs. | |
Offers excellent anaerobic coverage, should be used in combination with an agent covering GNRs and possibly Enterococcus species. | |
Excellent broad spectrum (Gram-positive, Gram-negative, and anaerobe) coverage; would reserve for seriously ill patients at high risk for resistant pathogens. | |
Excellent broad spectrum (Gram-positive, Gram-negative, and anaerobe) coverage; would reserve for seriously ill patients at high risk for resistant pathogens. | |
Newest carbapenem in the U.S., approved for complicated intra-abdominal infections in 2007. Excellent broad spectrum (Gram-positive, Gram-negative, including some carbapenem-resistant Pseudomonas species, and anaerobe) coverage, would reserve for seriously ill patients at high risk for resistant pathogens. | |
Very good Gram-negative coverage and Gram-positive coverage; use in combination with anaerobic agent (plus/minus an agent covering Enterococcus species) for empiric therapy |
FOLLOW UP
- Source control is essential. The open abdomen approach is occasionally necessary in severe infections.
- On-demand re-laparotomy rather than a planned re-laparotomy may be associated with better results in selected cases.
- If no clinical response within 3-5 days of antibiotic therapy and drainage, consider re-imaging to assess for undrained collections or other processes such as resistant pathogens.
- Follow up CT scan/US and/or sinograms are often needed to demonstrate resolution of source and abscess.
- Useful clinical parameters to follow include imaging studies, temperature, white blood cell count and possibly serum C-reactive protein.
- In select patients with spontaneous abscess from Crohn’s disease, reinstitution or optimization of immunosuppressants therapy may be appropriate soon after percutaneous drainage.
OTHER INFORMATION
- Multiple factors, including severity of illness, bacteremia, multiple abscesses, and location of abscess are predictive of mortality (even with treatment, mortality may still approach 30% depending on the population).
- Percutaneous drainage should be utilized IF possible and surgical source is controlled.
- Rate of recovery of yeast from intraoperative specimens of a perforated viscus was >30% and was associated with death and complications. Consider anti-fungal treatment if recovery of yeast from cultures and patient not clinically improving, or repeated recovery of yeast from cultures.
- Empiric coverage of yeast and Enterococci is adults with community-associated intra-abdominal infection is not necessary.
- Consideration of these organisms are reasonable if clinical response is not as expected.
Pathogen Specific Therapy
Pathogen | First-Line Agents | Second-Line Agents |
Anaerobes | Piperacillin/tazobactam, ticarcillin/clavulanic acid, ampicillin/sulbactam, imipenem, meropenem, doripenem, tigecycline, clindamycin. | |
Enterobacteriaceae | 3rd generation cephalosporins, fluoroquinolones | Pipercillin/tazobactam, ticarcillin/clavulanic acid, ampicillin/sulbactam, tigecycline, aminoglycosides, carbapenems for resistant pathogens |
Enterococci | Penicillin or ampicillin +/- gentamicin | Vancomycin +/- gentamicin, linezolid, daptomycin, tigecycline |
Streptococci | Cefazolin, etc. | |
Imipenem, meropenem, doripenem; ciprofloxacin or levofloxacin (if susceptible) | ||
Candida albicans or other Candida species | Fluconazole | Amphotericin B or lipid formulation products, |
MSSA Nafcillin or oxacillin, cefazolin MRSA Vancomycin | ||
Basis for recommendation
- Solomkin JS, Mazuski JE, Bradley JS, et al. Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. Clin Infect Dis. 2010;50(2):133-64. [PMID:20034345]
Comment: IDSA, SIS, ASM, and SIDP consensus guidelines
References
- Gregersen R, Mortensen LQ, Burcharth J, et al. Treatment of patients with acute colonic diverticulitis complicated by abscess formation: A systematic review. Int J Surg. 2016;35:201-208. [PMID:27741423]
Comment: Limited studies available, all observational. Failure rate in this group of 8766 patients was ~ 20%, regardless of non-operative treatment choice. Abscesses < 3 cm were sufficiently treated with antibiotics alone. Patients without operative intervention, 25% experienced a recurrent episode during long-term follow-up. When comparing percutaneous drainage (PAD) to antibiotic treatment, PAD was superior (15.9% vs. 22.2% failure rates). Patients undergoing acute surgery had increased risk of death (12.1% vs. 1.1%) compared to patients treated non-operatively. Of patients undergoing PAD, 2.5% experienced procedure-related complications and 15.5% needed adjustment or replacement of the drain. These sorts of studies are very prone to bias, so interpret results with caution.
- Jaffe TA, Nelson RC. Image-guided percutaneous drainage: a review. Abdom Radiol (NY). 2016;41(4):629-36. [PMID:26826090]
Comment: PAD is now the routine and preferred approach and may be a temporazing measure for those who need operative intervention. Compliation rates of PAD are relatively uncommon.
- Feagins LA, Holubar SD, Kane SV, et al. Current strategies in the management of intra-abdominal abscesses in Crohn's disease. Clin Gastroenterol Hepatol. 2011;9(10):842-50. [PMID:21679776]
Comment: Reviews strategies for managing intra-abdominal abscesses in Crohn’s disease; includes a management algorithm and a discussion on immunosuppression management during infection.
- Hammond NA, Nikolaidis P, Miller FH. Left lower-quadrant pain: guidelines from the American College of Radiology appropriateness criteria. Am Fam Physician. 2010;82(7):766-70. [PMID:20879699]
Comment: Guidelines for use of imaging modalities for LLQ pain utilizing ACR appropriateness criteria; includes case examples
- Mazuski JE, Solomkin JS. Intra-abdominal infections. Surg Clin North Am. 2009;89(2):421-37, ix. [PMID:19281892]
Comment: Review of management of a variety of intra-abdominal infections.
Rating: Important - Kumar RR, Kim JT, Haukoos JS, et al. Factors affecting the successful management of intra-abdominal abscesses with antibiotics and the need for percutaneous drainage. Dis Colon Rectum. 2006;49(2):183-9. [PMID:16322960]
Comment: Retrospective review assessing need for percutaneous drainage vs. antibiotic therapy alone.
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