Akhondi H and Sabih DE. StatPearls. StatPearls Publishing 2020 Jan– - Review.
A liver abscess is defined as a pus-filled mass in the liver that can develop from injury to the liver or an intraabdominal infection disseminated from the portal circulation. The majority of these abscesses are categorized into pyogenic or amoebic, although a minority is caused by parasites and fungi. Most amoebic infections are caused by Entamoeba histolytica. The pyogenic abscesses are usually polymicrobial, but some organisms are seen more commonly in them, such as E.coli, Klebsiella, Streptococcus, Staphylococcus, and anaerobes. While the incidence is low, it is essential to understand the severity of these abscesses because of the high mortality risk in untreated patients.
The usual pattern of abscess formation is that there is leakage from the bowel in the abdomen that travels to the liver through the portal vein. Many cases have an infected biliary tract that causes an abscess via direct contact.
Liver abscesses can be classified in a variety of ways: One is by location in the liver. 50% of solitary liver abscesses occur in the right lobe of the liver (a more significant part with more blood supply), less commonly in the left liver lobe or caudate lobe. Another method is by considering the source: If the cause is infectious, the majority of liver abscesses can be classified into bacterial (including amebic) and parasitic sources (including hydatiform cyst).