One article to master: the main points of diagnosis and treatment of liver abscess

Liver abscess is caused by microorganisms that invade the liver and multiply in it, resulting in space-occupying and purulent lesions of the liver.

The most common pathogens that cause liver abscess include: ▲ Bacterial liver abscess caused by a variety of bacterial infections, often called Pyogenic liver abscess (PLA), is the most common (80%).

The main pathogen of bacterial liver abscess in western countries is Escherichia coli, while the main pathogen in Asian countries is Klebsiella pneumoniae.

If the patient has pleural effusion, the possibility of Escherichia coli should be suspected, and the possibility of Klebsiella should be suspected when imaging pneumoperitoneum.

▲ Amebic liver abscess (ALA) caused by the infection of intrahepatic amoeba.

▲ Fungal liver abscess caused by fungus is the least common (less than 10%).
The most common pathogenic fungus is Candida.

Untreated purulent liver abscesses are still fatal, and the most common causes of death include sepsis, multiple organ failure, and liver failure.

Clinical manifestations of liver abscess The typical triad of liver abscess is: fever, chills, and abdominal pain, but the clinical symptoms of patients are often atypical.

The reasons for the atypical may be: (1) the elderly and multiple underlying diseases cause the patient to feel less discomfort such as abdominal pain; (2) the liver abscess is small in the early stage or the location is deep and does not touch the liver capsule; (3) the disease is difficult to delay the disease with antibiotics in the early stage Differentiate from other infections.

In patients with liver abscess, chest pain and other pulmonary symptoms should not be ruled out, and the liver abscess should be suspected of being mixed infection.

Due to the high mortality of patients with pulmonary infection, routine chest imaging and respiratory function monitoring still cannot be ignored.

Table 1 Common clinical manifestations and pathogenesis of PLA Take PLA as an example.
When bacteria reach the liver, the endotoxin produced by bacteria stimulates the proliferation of hepatic macrophages, which play a phagocytic effect and produce toxic mediators that can regulate microvascular responses.

After the bacteria adhere, they can leak out through cell junctions, and the resulting inflammatory substances can cause sinus cavity blockage and further block blood vessels.

These phenomena can inhibit sodium and potassium pumps, leading to cholestasis.

The route of infection can determine the location and number of abscesses: (1) The infection is invaded by the portal vein system, and several abscesses may appear, mostly confined to the right lobe of the liver; after portal vein septic thrombosis, left lobe abscess can be caused.

(2) Invasion by the arterial circulation can form several small abscesses evenly distributed in the two lobes of the liver.

The most common abnormalities of liver function in laboratory tests are hypoproteinemia, elevated phosphatase, and transaminase and bilirubin may not necessarily be elevated.

The blood test showed leukocytosis (>15×10^9/L) and neutrophils increased.

In general bacterial infections, the increase of white blood cells, especially the increase of neutrophils, can better reflect the severity of inflammation.

However, if anemia, leukopenia, and prolonged clotting time occur, Klebsiella infection should not be ruled out.

Due to the difference in treatment and prognosis, it is very important to distinguish between PLA and ALA (see Table 2).

Table 2 Differential diagnosis of amoebic liver abscess and purulent liver abscess The gold standard for PLA is microbiological examination, and pus/blood specimens are taken for Gram staining and culture.

For ALA, more than 90% of patients can detect anti-endomeba antibodies in the serum: indirect hemagglutination test (IHA)> 1:512; enzyme-linked immunoassay (EIA) is also often used; if ALA can be performed For abscess puncture, it is recommended to perform Gram staining and culture on the puncture.

Ultrasound is the first choice for imaging examinations.

The abscess is a space-occupying lesion with a hypoechoic, round or oval shape and a clear boundary.

Although the specificity of ultrasound can reach more than 85%, there are deviations in the observation of the characteristics of the air cavity and separation of the abscess.

CT specificity can reach more than 95%.

A liver abscess with a diameter of about 0.
5 cm can be found by CT.

"Petal sign" and "cluster sign" and indirect signs of biliary tract can be used as strong evidence for the diagnosis of atypical liver abscess in CT examination.

The specificity and sensitivity of MRI are not as obvious as the above two, but the "circular target sign" of MRI is also an important clue for the diagnosis of liver abscess.

Chest X-ray can indicate elevation of the right diaphragm, lung insufficiency, and pleural effusion.

Treatment of most PLA can be cured with antibiotics combined with pus aspiration.

Specific treatment methods include: (1) antibiotics + ultrasound guided percutaneous liver abscess drainage; (2) antibiotics + liver abscess incision and drainage; (3) antibiotics + partial liver resection.

Antibiotic treatment includes the combined use of broad-spectrum antibiotics: third-generation cephalosporins plus clindamycin or metronidazole; broad-spectrum penicillins plus aminoglycosides; second-generation cephalosporins plus aminoglycosides.

Color Doppler ultrasound or CT guided percutaneous drainage and drainage of liver abscess has become the main treatment for liver abscess.

Treatment after puncture: After placing the tube as far as possible to drain the pus, flush with metronidazole solution and/or gentamicin + normal saline, 1-2 times every 12-24 hours to keep the drainage tube unobstructed and the amount of flushing Basically maintain a balance of access and exit, leave a small amount of antibiotics after flushing and drain with negative pressure.

For those with thick pus and necrotic tissue, dilute with normal saline or add chymotrypsin or trypsin solution to wash and dissolve.

The indications for puncture or catheter drainage are as follows: (1) Liver abscesses with ineffective medical treatment or with a continuous increase in body temperature; (2) Liver abscesses with abscess wall formation and liquefaction of the abscess to mature; (3) Abscesses with a diameter of 3-5 cm Abscess can be punctured and drained.
Abscesses with a diameter of more than 5 cm can be drained; (4) Liver abscesses with normal coagulation function and intolerance to surgery. Abscess incision and drainage is mainly suitable for: (1) liver abscesses with systemic symptoms or clinical symptoms that have not been significantly improved by active drug treatment and interventional therapy; (2) liver abscesses with ruptured abscesses and obvious lung infections such as empyema, pleurisy, etc.
(3) Liver abscesses where intervention or drugs are difficult to achieve effect through thick abscess wall; (4) Liver abscesses that need to relieve biliary obstruction or other biliary tract diseases; (5) Liver abscesses with special locations; (6) Carcinogenesis is not excluded Liver abscess; (7) multiple liver abscess.

References: [1] Huang Yang.
Progress in the diagnosis and treatment of bacterial liver abscess[J].
Journal of Clinical Hepatobiliary Diseases, 2018(3):641-644.
[2] Eugene R.
Schiff, Willis C.
Maddrey.
Michael F.
Scorell.
Schiff's Diseases of the Liver [M].
11th ed.
2012.
[3] Lu Zhanxing, Chen Xinhui.
CT-guided percutaneous catheterization and drainage for the treatment of liver abscess[J].
Journal of Practical Radiology, 2014,(8):1373 -1375.
[4] Ruben Peralta.
Liver Abscess.
Medscape.
Jun 12, 2018.