Amebic intestinal disease is often complicated by amebic liver abscess, accounting for approximately 1.8–10% of domestic clinical data, with some reports as high as 46%. Foreign autopsy materials indicate a range of 10–59%. In recent years, with effective medications and, when necessary, the addition of accurate ultrasound-guided pus drainage, the condition has become relatively easy to control.

bubble_chart Clinical Manifestations

The onset is relatively slow, the course of illness is prolonged, and there may be high fever, irregular fever, and night sweats.

bubble_chart Diagnosis

Before the onset of the disease, there was a history of dysentery or diarrhea, followed by fever, liver pain, and hepatomegaly. Amoebic trophozoites were found in the stool, and ultrasound imaging revealed a poorly defined liquid occupying lesion in the liver. Additionally, typical chocolate-like pus was obtained through puncture, leading to the diagnosis.

bubble_chart Treatment Measures

There are three key points in treatment: anti-amoebic drugs, repeated aspiration of pus when necessary, and supportive therapy. Surgical treatment is only suitable for individual patients.

The first-choice anti-amoebic drug is metronidazole, as it is highly effective, safe, and also has anti-anaerobic activity, allowing most patients to avoid aspiration of pus, with a cure rate of 70–90%. Chloroquine and emetine also have high efficacy but greater toxicity and can serve as alternatives to metronidazole. For patients with concurrent bacterial infections, appropriate antibacterial drugs can be selected.

Percutaneous liver aspiration of pus was once an extremely important and effective treatment for this condition. After the introduction of metronidazole, most cases no longer require aspiration, but some patients still need it. The key points are: ① Begin anti-amoebic therapy and necessary supportive treatment 3–5 days before aspiration; ② A thorough ultrasound examination must be performed before aspiration to determine the size, number, and location of the abscess(es) as well as the puncture route; ③ Choose a puncture site closest to the abscess cavity but without traversing the pleural cavity; ④ Strict aseptic technique must be observed; ⑤ Use a needle of appropriate thickness, aspirate as completely as possible each time, but excessive negative pressure may cause bleeding; ⑥ After aspiration, ultrasound can be used to verify the cavity, and antibacterial drugs can be injected to prevent secondary infection. Typically, aspiration is performed 2–3 times per week, with frequency reduced as pus decreases.

For abscesses that are too large or complicated by bacterial infection and cannot be effectively controlled by aspiration, closed drainage may be considered. This involves inserting a plastic or silicone tube of appropriate size and flexibility through a trocar, but secondary infection must be prevented post-drainage. If complications involve penetration into nearby body cavities, appropriate drainage should also be performed. Open drainage should be strictly selected. For chronic thick-walled abscesses unresponsive to the above treatments, partial liver resection may also be considered.

bubble_chart Differentiation

①Bacterial liver abscess: Often preceded by a history of suppurative diseases such as biliary tract or appendicitis, the onset is sudden and severe, usually accompanied by obvious septic symptoms. The white blood cell count, especially neutrophils, is significantly elevated. Ultrasound often reveals multiple abscesses. The pus obtained by puncture is typically yellowish-white and foul-smelling, with bacteria visible on smear or culture. Metastatic abscesses often occur, and anti-amoebic treatment is ineffective. However, it is difficult to distinguish from amoebic liver abscess with secondary bacterial infection. ②Liver cyst: Usually not difficult to differentiate. However, in cases of chronic amoebic liver abscess without obvious clinical inflammatory manifestations or infected liver cysts, careful differentiation is necessary. Ultrasound imaging and the characteristics of the aspirated pus aid in differentiation. ③Hydatid cyst of the liver: Generally not difficult to distinguish, but in cases of infected hydatid cysts, careful examination is advisable. A history of residence in an endemic area and a positive hydatid skin test are two key features of hepatic hydatid disease. ④Primary liver cancer: Differentiation is necessary in cases where central tumor necrosis and liquefaction are accompanied by tumor fever, especially when the amoebic liver abscess is not fully mature (i.e., not completely liquefied), making distinction challenging. In such cases with incomplete liquefaction, liver puncture should be performed cautiously. However, differentiation is possible by considering a background of hepatitis, cirrhosis, or hepatitis B virus infection, a positive AFP, ultrasound showing a space-occupying lesion with a halo, etc. A reduction in fever after chloroquine treatment does not completely rule out liver cancer, and careful analysis is required. Sometimes, short-term follow-up to observe dynamic changes is necessary.