Liver abscess

Background

Microbiology

• Pyogenic
  • Gram-negative bacteria
    • Escherichia coli
    • Klebsiella species
    • Less common: Pseudomonas aeruginosa, Proteus, Enterobacter, Citrobacter, and Serratia
  • Gram-positive bacteria
    • Streptococcus species, especially anginosus group
    • Enterococcus species
    • Other Viridans group streptococci
    • Less common Staphylococcus aureus and Streptococcus pyogenes
  • Anaerobes
    • Bacteroides species
    • Less common: Fusobacterium, anaerobic streptococci, Clostridium species, Lactobacillus
• Amebic
  • Entamoeba histolytica

Etiology

• Pyogenic
  • Biliary: most common mechanism, includes ascending cholangitis
  • Hematogenous via hepatic artery: from bacteremia
  • Hematogenous via portal vein: from an infection abdominal organ duch as diverticulitis, pancreatitis, or appendicitis
  • Contiguous spread
  • Trauma: including things like ingested toothpicks
  • Cryptogenic: second most common mechanism is "unknown"
• Amebic: see Entamoeba histolytica

Management

• Get source control
• Treat for 4-6 weeks, ensuring radiological resolution of abscess