Liver Abscess

In underdeveloped countries, hepatic abscesses have a relatively high incidence and are usually caused by parasitic infections (eg, Entamoeba histolytica, echinococcal). In contrast, hepatic abscesses are uncommon in developed countries and are caused by bacterial infection in about 80% of cases.

Staph. aureus can cause hepatic abscesses via hematogenous seeding of the liver. Enteric bacteria (eg, E. coli, Klebsiella, and enterococci) can cause it by ascending the biliary tract (ie. ascending cholangitis), portal vein pyemia, or direct invasion from an adjacent area (eg, cholecystitis)

Pyogenic liver abscess

Pyogenic liver abscesses occur when bacterial infection leads to a collection of pus within the liver, most commonly via biliary seeding, portal venous spread from intra-abdominal infection, or haematogenous spread. Staphylococcus aureus is the typical pathogen in children, whereas Escherichia coli predominates in adults.

Typical presentation

• fever, rigors and right upper quadrant abdominal pain
• anorexia, nausea and malaise
• hepatomegaly or right upper quadrant tenderness on examination
• jaundice may occur in biliary-associated abscesses

Risk factors

• biliary tract disease (e.g. stones, strictures, cholangitis)
• intra-abdominal sepsis (e.g. appendicitis, diverticulitis, perforated bowel)
• diabetes mellitus
• immunosuppression (e.g. steroids, chemotherapy)

Investigations

• raised inflammatory markers and deranged LFTs (particularly ALP and GGT)
• blood cultures often positive
• ultrasound or CT abdomen to confirm presence, size and number of abscesses
• microbiological sampling during drainage