Here's what you need to know about liver abscess

Liver abscess is a very common disease in daily life. When the disease is serious, it can directly endanger life safety. Therefore, it is particularly important to have a certain understanding of it. Liver abscess is usually divided into bacterial liver abscess, fungal liver abscess and amoebic liver abscess. Different types of symptoms require different treatments. Its symptoms generally include fever, chills, pain in the liver area, general fatigue, nausea, vomiting, and loss of appetite. If the above symptoms are found, the patient needs to seek medical treatment in time to recover health as soon as possible.

1. Disease Classification

Liver abscess is usually divided into three types. Bacterial liver abscess is often a mixed infection caused by multiple bacteria, accounting for about 80%, amoebic liver abscess is about 10%, and fungal liver abscess is less than 10%. The most common pathogens causing bacterial liver abscess are Escherichia coli and Streptococcus. The main route of infection of bacterial liver abscess is the bile duct, followed by the portal vein system and the systemic blood circulation system.

2. Epidemiology

A US statistical data shows that the incidence of liver abscesses found in autopsies during the periods 1898-1933, 1934-1958, and 1959-1968 was 0.7%, 0.45%, and 0.57%, respectively. The incidence of liver abscesses in hospitalized patients is approximately 8-16/100,000. Liver abscess often occurs in people aged 60-70 years old, with no obvious gender difference, but the prognosis for men is relatively poor. The mortality rate of liver abscess without any treatment is extremely high, but if it can be treated with anti-infection, drainage and other treatments in time, the mortality rate is about 5-30%. The most common causes of death included sepsis, multiple organ failure, and liver failure.

3. Clinical manifestations

Common clinical manifestations of liver abscess include high fever, chills, pain in the liver area, fatigue, loss of appetite, nausea, vomiting and other digestive tract discomforts.

4. Diagnosis and Differentiation

A preliminary diagnosis can be made based on the medical history of systemic or biliary infection, combined with clinical manifestations such as high fever, pain in the liver area, nausea, vomiting, and loss of appetite. Most patients have a significant increase in white blood cell count, with the total count reaching 20-30×10^9/L, and liver enzymes, bilirubin, and alkaline phosphatase may be elevated. X-ray examination may show enlarged liver shadow, elevation of the right diaphragm, localized bulge and limited movement, or accompanied by right lower lung atelectasis, pleural reaction or pleural effusion or even empyema. Air-fluid interface can be seen in a few abscesses infected with gas-producing bacteria or those that penetrate the bronchus. The diagnosis can basically be confirmed by combining abdominal BUS and enhanced CT scan. BUS can measure the location, size and depth of the abscess from the body surface, providing convenience for determining the abscess puncture point or surgical drainage route. It can be used as the preferred examination method, and its positive diagnostic rate can reach more than 96%. On plain CT scan, single or multiple round or oval low-density lesions can be seen. The edges of the lesions are mostly blurred or partially clear, and the density is uneven. The CT value of the central area is slightly higher than water and lower than normal liver parenchyma. Bubbles can be seen in some lesions. A ring-like band appears around the abscess, called the target sign, which can be single, double or triple rings. After enhancement, the density of the abscess cavity does not change, but the cavity wall has an irregularly increased density enhancement, which is called the "lunar sign" or "halo sign". Multilocular abscess shows single or multiple septa, most of which are enhanced and present honeycomb-like changes. The differential diagnosis of bacterial, amebic and fungal liver abscesses is shown in the table below. It also needs to be further differentiated from cholelithiasis, cholecystitis, empyema, pleurisy, acute gastritis, liver cancer, echinococcosis and pneumonia.