Liver Abscess

Definition

A liver abscess is a localized collection of pus within the liver parenchyma, caused by bacterial, amoebic, or rarely fungal infections. It can be life-threatening if not promptly diagnosed and treated.

Epidemiology

• More common in men than women, peak incidence between 30–50 years
• Amoebic liver abscess prevalent in tropical and subtropical regions, especially India, Africa, and Latin America
• Pyogenic liver abscess more common in elderly and immunocompromised patients
• Incidence higher in patients with biliary disease, diabetes, or immunosuppression
• Mortality reduced to <10% with early diagnosis and appropriate therapy

Etiology

• Pyogenic: typically polymicrobial; common organisms include E. coli, Klebsiella pneumoniae, Streptococcus species, and anaerobes
• Amoebic: caused by Entamoeba histolytica
• Fungal: Candida species, rare and usually in immunocompromised patients
• Risk factors: biliary tract disease, portal vein seeding from intra-abdominal infections, hematogenous spread, diabetes, immunosuppression
• Post-traumatic or post-surgical abscess possible

Pathophysiology

• Pathogen gains access via biliary tract, portal vein, hepatic artery, or direct extension from contiguous infection
• Local inflammatory response leads to hepatocyte necrosis and pus formation
• Encapsulation occurs over time, forming an abscess cavity
• Systemic inflammatory response may lead to fever, malaise, and sepsis
• Untreated abscess can rupture into peritoneum, pleura, or pericardium