PATHOGENS

CLINICAL

  • Pyogenic hepatic abscesses generally occur in middle-aged adults (40’s and 50’s).
  • Signs and symptoms: include fever +/- RUQ pain, tenderness w/ hepatomegaly.
    • Some may only have fever (60%) associated with chills and malaise.
    • Presentation may be subacute or chronic including weight loss, anorexia.
    • Occasionally, patients may be acutely ill with mental status changes.
    • Rarely, patients may present with sepsis and peritoneal signs from intraperitoneal rupture of the abscess.
  • Approximately 50% of patients have a solitary hepatic abscess.
    • Majority of abscesses involve in the right hepatic lobe (~75%), less commonly left (20%) or caudate (5%) lobes.
    • Diaphragmatic irritation from abscess may refer pain to the right shoulder +/or cough or pleural rub.
  • Classified by presumed origin:
    • Up to 50% develop from biliary tract (cholangitis).
    • Remainder are from hepatic artery (bacteremia), portal vein (abdominal source, e.g. diverticulitis), contiguous focus (local abscess or cholecystitis) or penetrating trauma.
    • Many are of cryptogenic origin.
    • Entamoeba histolytica: abscess occurs via the portal system during colitis.
      • Typically manifests as a right lobe solitary lesion.
      • Rare in the Untied States, occurring almost exclusively in immigrants and travelers.
      • Men, especially MSM, at higher risk for invasive disease.
    • Echinococcal, or hydatid cysts: most commonly caused by Echinococcus granulosus and usually acquired from canines (sheep dogs).
      • Rarely seen in the United States.
      • Usually asymptomatic until symptoms develop due to size of enlarging cyst or leakage/rupture.
  • Underlying disease typically is the primary determinant of outcome.

DIAGNOSIS

  • For pyogenic liver abscess(es), positive blood cultures are found in up to 50%, with alkaline phosphatase and WBC counts frequently elevated. Hyperbilirubinemia with or without jaundice occurs in < 50% of patients.
  • Although dx may be suggested on plain films (e.g., gas within the abscess), CT, US, and MRI are the imaging modalities of choice in suspected liver abscess or FUO.
  • CT or US-guided percutaneous drainage or surgical drainage should be considered in all cases of hepatic abscess for diagnostic confirmation and culture.
  • Positive amebic or echinococcal serology helps differentiate parasitic liver abscess from pyogenic, especially in nonendemic areas. Serology cannot distinguish between active and prior infection.
  • Uncomplicated small abscesses due to Entamoeba histolytica in endemic areas may not require aspiration; consider empirical rx.

TREATMENT

Drainage and General Management

  • Abscess drainage is the optimal therapy for pyogenic liver abscesses.
    • Aspirate should be sent for gram stain and aerobic/anaerobic culture; evaluation for fungal and mycobacterial pathogens. E. histolytica should be considered based on epidemiologic factors.
  • CT or US-guided percutaneous needle aspiration +/- catheter drainage initial method of choice:
    • Success in up to 90% of cases.
    • If drainage inadequate, surgical drainage may be required.
    • Percutaneous aspiration without catheter placement: recently found to have similar success rates as catheter placement.
      • Repeat aspiration required in approximately 50%.
      • Catheter placement should be considered in larger abscesses (>5 cm diameter).
    • Complications of percutaneous drainage: include perforation of adjacent abdominal organs, pneumothorax, hemorrhage and leakage of abscess contents in peritoneum.
  • General recommendations are for at least one week of drainage with CT follow-up.
  • Surgical drainage: may consider as primary treatment in certain settings.
    • Complex abscess
    • Multiple abscesses
    • Percutaneously unreachable abscess
    • Larger abscesses (> 5 cm)
    • If associated surgical problem also present
    • Drainage may be done laparoscopically
  • Hepatotomy: generally successful approach, but improvements in percutaneous techniques make it secondary management in most cases.
  • Medical management: consider in patients at high risk for drainage procedures or with small/multiple abscesses not amenable to drainage.

Antibiotic treatment

  • Empiric coverage should include Enterobacteriaceae, enterococci, anaerobes, and in certain situations staphylococci and streptococci.
    • In a stable patient antibiotics may be deferred until post-aspiration/drainage to increase culture yield.
    • Consider empiric antifungal treatment in immunosuppressed patients at risk for chronic disseminated candidiasis (CDC, a.k.a. hepatosplenic candidiasis, also see C. albicans module).
    • Culture results may help narrow coverage, but for pyogenic abscess do not discontinue anaerobic coverage given difficulty culturing these organisms.
  • Empiric regimens: may narrow based on culture results.
    • Ampicillin 2.0g IV q6h plus gentamicin 1.7mg/kg IV q8h plus metronidazole 0.5g IV q8h
    • Alternatives:
      • Cefotaxime 2.0g IV q8h or ceftriaxone 2.0g IV q24h plus metronidazole 0.5g IV q8h
      • Piperacillin/tazobactam 3.375g IV q 6h
        • Consider adding metronidazole if amebic liver abscess a possibility.
      • Carbapenems: appropriate for monotherapy, especially if the patient is at high risk for resistant GNRs or has a documented multidrug-resistant organism.
        • Ertapenem
        • Imipenem
        • Meropenem
        • Doripenem
      • Fluroquinolones: often used as an oral regimen for prolonged therapy after completion of initial parenteral therapy course.
        • Ciprofloxacin, levofloxacin or moxifloxacin plus metronidazole
  • Duration: if adequate drainage achieved with resolution of fever and leukocytosis.
    • Often 14-42 days total.
    • Longer courses (up to several months) may be required in the patient who is inadequately drained or treated without drainage.
    • Follow-up imaging studies: consider in patients with suboptimal clinical response.
      • Use CT or ultrasound.
      • Note: imaging findings may lag behind other clinical markers of response.

Amebic hepatic abscess

  • See Entameoba histolytica module for additional details.
  • Preferred:
    • Metronidazole 750mg PO three times a day x 7-10 days as a tissue agent, followed by a luminal agent to eliminate residual colonic colonization, usually paromomycin 500mg three times a day PO x 7d.
    • Alternatives:
      • Tissue agent: tinidazole 800mg three times a day or 2g +daily x 3-5d.
    • Luminal agents:
  • Percutaneous aspiration has no clear role in therapy, but consider for diagnosis if uncertain (serology inconclusive or not available) or no response to appropriate antibacterial therapy.
    • Predictors of need for aspiration: include age> 55 years, abscesses > 5 cms, involvement of both lobes of liver and failure of medical therapy after 7 days.

Hydatid (Echinococcal) cyst

  • Most commonly E. granulosus, see module for additional details.
  • Serology usually helpful in most cases.
  • In patients with rupture of the cyst in the biliary tree, transient but markedly elevated levels of alkaline phosphatase and bilirubin may occur. Hyperamylasemia and eosinophilia occur in up to 60%.
  • Surgical resection standard intervention:
    • Uncomplicated cysts: PAIR (Percutaneous puncture with CT or US guidance, followed by Aspiration, Injection of a protoscolicidal agent such as hypertonic saline or ethanol, and finally Re-aspiration 15 minutes later) is becoming more accepted treatment of choice at some centers due to high success rates with low morbidity.
  • Open or percutaneous (PAIR) procedures should be combined with albendazole treatment.

Selected Drug Comments

Drug

Recommendation

Ampicillin/sulbactam

Good coverage of Gram-positive, Gram-negative, and anaerobic pathogens - lacks Pseudomonas aeruginosa coverage but good Enterococcus species coverage. Rising rates of resistance in E. coli mean that this is no longer a favored empiric choice, but may be quite acceptable once culture results have returned.

Cefepime

Excellent coverage of gram negative w/ some Gram positive pathogens; use in combination with anaerobic agent for empiric therapy.

Imipenem/cilastatin

Excellent broad spectrum (Gram-positive, Gram-negative, and anaerobe) coverage; would reserve for seriously ill patients. Has better coverage for E. faecalis than meropenem or doripenem; none of the carbapenems cover E. faecium.

Meropenem

Excellent broad spectrum (gram-positive, gram-negative, and anaerobe) coverage; would reserve for seriously ill patients. Will cover E. faecalis; none of the carbapenems cover E. faecium.

Ertapenem

Once daily carbapenem with excellent broad-spectrum coverage except P. aeruginosa, Acinetobacter spp., and enterococci.

Doripenem

Newer carbapenem approved recently for complicated IAIs. Excellent gram-positive (except E. faecium), Gram-negative and anaerobic coverage.

Moxifloxacin

Excellent broad-spectrum coverage includes anaerobic activity, many would still use with metronidazole with liver abscess condition.

Piperacillin/tazobactam

Excellent broad spectrum coverage including Gram-positive and Gram-negative coverage (including Pseudomonas aeruginosa and β-lactamase producing pathogens) and anaerobic coverage.

Ticarcillin/clavulanic Acid

Broad spectrum coverage including Gram-positive coverage, Gram-negative coverage (including Pseudomonas aeruginosa [but less active than piperacillin/tazobactam] and B-lactamase producing pathogens) and anaerobic coverage.

Metronidazole

Remains premier anti-anaerobic drug, and preferred for pyogenic abscesses in combination therapy, also treats amebic liver infection.

Tigecycline

Broad spectrum agent related to minocycline, with excellent gram-positive (including MRSA and VRE), Gram-negative (except Pseudomonas aeruginosa and Proteus mirabilis) and anaerobic activity, approved for complicated intraabdominal infections.

FOLLOW-UP

  • Untreated, the mortality rate associated with pyogenic hepatic abscess approaches 100%.
  • With treatment, in some series, mortality is below 15%; the latter mortality is dependent upon underlying disease.
  • Recurrence is more frequent after simple percutaneous aspiration without placement of a temporary drain, or in patients in whom drains are removed too early.

OTHER INFORMATION

  • Hepatic abscesses are frequently polymicrobial.
  • Single/multiple lesions occur in approximately a 1:1 ratio, with the majority in the right lobe (especially when solitary); cryptogenic abscesses are generally solitary.
  • Abscesses are frequently associated with chronic medical conditions (e.g., diabetes), hematologic disease (e.g., leukemia), and chronic granulomatous disease (Staphylococcus aureus).
  • Chronic disseminated candidiasis (CDC, a.k.a. hepatosplenic candidiasis) occurs in immunosuppressed patients, e.g. bone marrow transplant recipients.

Basis for recommendation

  1. Author opinion

    Comment: Recommendations in this module are based on literature given lack of robust RCT data and guideline statements.

References

  1. Lambertucci JR et al: Pyogenic abscesses and parasitic diseases. Rev Inst Med Trop Sao Paulo 43:67, 2001 Mar-Apr  [PMID:11340478]

    Comment: Association of underlying parasitic disease and superinfection with bacteria.

  2. Benedetti NJ, Desser TS, Jeffrey RB: Imaging of hepatic infections. Ultrasound Q 24:267, 2008  [PMID:19060716]

    Comment: Review of imaging of hepatic abscesses and other hepatic infections.

  3. Yu SC et al: Treatment of pyogenic liver abscess: prospective randomized comparison of catheter drainage and needle aspiration. Hepatology 39:932, 2004  [PMID:15057896]

    Comment: Compares catheter drainage versus needle aspiration.

  4. Kurland JE, Brann OS: Pyogenic and amebic liver abscesses. Curr Gastroenterol Rep 6:273, 2004  [PMID:15245694]

    Comment: Review of the most common infectious causes of abscess disease in the liver.
    Rating: Important

  5. Nasseri-Moghaddam S et al: Percutaneous needle aspiration, injection, and re-aspiration with or without benzimidazole coverage for uncomplicated hepatic hydatid cysts. Cochrane Database Syst Rev [PMID:21249654]

    Comment: No RCTs identified to support or refute role of PAIR procedure with or without benzimidazole for hydatid cysts.

  6. Khan R et al: Predictive factors for early aspiration in liver abscess. World J Gastroenterol 14:2089, 2008  [PMID:18395912]

    Comment: Predictive factors for early aspiration in liver abscess

  7. Reid-Lombardo KM, Khan S, Sclabas G: Hepatic cysts and liver abscess. Surg Clin North Am 90:679, 2010  [PMID:20637941]

    Comment: Contains a review of pyogenic (including a breakdown of pyogenic causes and microbiology) and parasitic (including hydatid cyst and amoebic) liver abscesses.

  8. Siu LK et al: Klebsiella pneumoniae liver abscess: a new invasive syndrome. Lancet Infect Dis 12:881, 2012  [PMID:23099082]

    Comment:
    Provides an overview of clinical features and management of hepatic abscesses caused by Klebsiella.

  9. Solomkin JS et al: Guidelines for the selection of anti-infective agents for complicated intra-abdominal infections. Clin Infect Dis 37:997, 2003  [PMID:14523762]

    Comment: Consensus, evidence-based general guidelines from IDSA, SIS, ASM, and SIDP.

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Last updated: March 14, 2013