Pyogenic liver abscess

1.peritonitis due to leakage of intraabdominal bowel contents that subsequently spread to liver via the portal circulation
2.or via direct spread from biliary infection. Gallstone/malignancy
3.from arterial hematogenous seeding in the setting of systemic infection. staph/strep

 commonly involve the right lobe of the liver, probably because it is larger and has greater blood supply. Liver abscess may also be accompanied by pylephlebitis.

 Risk factors include diabetes, underlying hepatobiliary or pancreatic disease, and liver transplant  Geographic and host factors - primary invasive liver abscess syndrome due to K. pneumoniae has been described in East Asia.

 Association with colorectal neoplasia — Several studies from Asia

MICROBIOLOGY —Most pyogenic liver abscesses are polymicrobial; mixed enteric facultative and anaerobic species are the most common pathogens. Anaerobes are probably under-reported because they are difficult to culture

• The Streptococcus milleri or S. anginosus group (including S. constellatus and S. intermedius) should search for simultaneous metastatic infections at other locations.
• S. aureus, S. pyogenes, and other Gram positive cocci - in patients who underwent transarterial embolization for hepatocellular carcinoma,  
• Candida species -chemotherapy and presents with recovery of neutrophil counts following a neutropenic episode.
• Klebsiella pneumoniae 
• Tuberculous liver abscesses are uncommon but should be considered when typical pyogenic organisms are not recovered from cultures 
• Burkholderia pseudomallei (the agent of Melioidosis) should be considered in patients from endemic areas (Southeast Asia and Northern Australia). 
• Amebiasis, in patients who are from or have traveled to an endemic area within the past six months. 

DIAGNOSIS — 

CT usually shows a fluid collection with surrounding edema. stranding / loculated subcollections. Pyogenic VS  amebic abscess by imaging studies 

Abscesses VS tumors and cysts. Tumors-solid radiographic /calcification. Necrosis and bleeding within a tumor may lead to a fluid-filled appearance;-difficult to differentiate,
Cysts appear as fluid collections without surrounding stranding or hyperemia.

An elevated right hemidiaphragm, right basilar infiltrate, or right-sided pleural effusion can be seen in 25- 355 of cases

 MRI and tagged white blood cell scans are less useful for distinguishing abscess from other causes of liver mass.

Microbial cultures — from CT or ultrasound-guided aspiration -gram stain and culture (both aerobic and anaerobic-specifically requested

Blood cultures + in up to 50% of case
Cultures obtained from existing drains are NOT adequate for guiding antimicrobial therapy, since they are often contaminated with skin flora and other organisms.

include leukocytosis, hypoalbuminemia, and anemia (normochromic, normocytic).

TREATMENT —

Drainage — Drainage techniques include CT-guided or ultrasound-guided percutaneous drainage (with or without catheter placement), surgical drainage, or drainage by ERCP.

single abscesses  ≤5 cm, either percutaneous catheter drainage or needle aspiration is acceptable - remain in place until drainage is minimal (7days). Repeat needle aspiration may be required in up to half of cases if a catheter is not left in situ.

diameter >5 cm, catheter drainage is preferred over needle aspiration. success 100% VS 50%
surgical intervention over percutaneous drainage -no difference in mortality, morbidity, duration of fever or complication rates. treatment failure 7 VS 28 %
Surgical drainage

• Multiple abscesses
• Loculated abscesses
• Abscesses with viscous contents obstructing the drainage catheter
• Underlying disease requiring primary surgical management
• Inadequate response to percutaneous drainage within seven days

Multiple or loculated abscesses may be successfully managed by percutaneous drainage;

ERCP can be useful for drainage of liver abscesses in patients with previous biliary procedures whose infection communicates with the biliary tree.




 Recovery of more than one organism should suggest polymicrobial infection including anaerobes, even if no anaerobes are isolated in culture. In such circumstances, anaerobic coverage should be continued.

Duration of therapy — 

no RCT 

difficult to drain or slow to resolve - require longer courses of therapy.

 temperature,WBC and CRP.
Follow-up imaging if persistent clinical symptoms or if drainage is not proceeding as expected; radiological abnormalities resolve more slowly than clinical and biochemical markers.

4-6w:  good response to initial drainage 2-4w of parenteral therapy,
 incomplete drainage 4-6weeks of parenteral therapy. The remainder of the course can then be completed with oral therapy. If culture results are not available, reasonable empiric oral antibiotic choices include amoxicillin-clavulanate alone or a fluoroquinolone (ciprofloxacin or levofloxacin) plus metronidazole.