Amoebic liver abscess is an accumulation of purulent exudate in the liver separated from the surrounding tissues due to the pathogenic effects of dysentery amoeba, The pathology manifests itself in pain in the right hypochondrium of varying intensity, hepatomegaly, fever, chills, sweating, jaundice of the skin and sclera, nausea and vomiting. Diagnosis is based on examination data, ultrasound of the liver, stool analysis, serological examination of blood. Conservatively prescribe antiprotozoal, antibacterial drugs. According to the indications, percutaneous or open aspiration and sanitation of the abscess cavity are performed.
Amoebic liver abscess is a purulent-inflammatory disease characterized by the formation of one or more isolated cavities in the hepatic parenchyma as a result of pathogenic amoebic invasion. The abscess is more often located in the right lobe of the organ, and its contents are represented by a thick brown exudate (“anchovy paste”). Liver damage on the background of intestinal amoebiasis is observed in 25% of cases. The disease occurs mainly in young and middle-aged men (30-45 years old). Pathology is common in countries with tropical and subtropical climates (areas of South America, Asia, Africa), in the middle band the peak incidence occurs in the summer.
Causes of amoebic liver abscess
Amoebic liver abscess is caused by a single–celled parasite – dysentery amoeba Entamoeba histolytica. The pathogenic microorganism enters the human gastrointestinal tract enterally when drinking infected water, plant products, in contact with contaminated household items (plates, spoons, etc.). The source of infection is a sick person or a carrier of amoebiasis. In the intestine, the parasite enters the active phase, multiplies and feeds on the biological material of the host (bacteria, blood cells). After reaching its highest form of development (tissue), the amoeba will enter the liver through the submucosal layer of the intestine through the portal vein system, where it continues its life cycle and reproduction.
According to the observations of specialists in the field of hepatology and abdominal surgery, the development of pathology increases in people who abuse alcohol, take glucocorticoid drugs, have undergone chemotherapy and radiation therapy and have oncological diseases. Young people and pregnant women are more susceptible to the disease.
Once in the liver with the blood flow, parasites, through the release of proteolytic enzymes, have a toxic effect on hepatocytes, causing their decay and destruction. As a result, melting and necrosis of a limited area of the parenchyma occurs with the formation of single or multiple isolated cavities filled with necrotic masses and products of the vital activity of the microorganism. With the further course of the disease, the contents of the abscess may become infected (more often with E. coli) with the development of a purulent-inflammatory process and staining of the contents in yellow-green color. In rare cases, self-sterilization of an amoebic abscess occurs, in which the exudate acquires a pasty consistency and a dark brown color.
Amoebic liver abscesses can be single and multiple. A single (solitary) abscess, increasing in size, sometimes reaches 10-15 cm in diameter. Multiple abscesses occur rarely and have a small diameter (from 0.5 to 2 cm). There are acute and chronic course of the disease. The acute form occurs suddenly and is accompanied by hectic fever, pronounced signs of intoxication. With a chronic course, the temperature is more often subfebrile, the pathology proceeds without bright clinical manifestations with periods of exacerbation and remission.
Symptoms of amoebic liver abscess
The clinical picture of liver abscess depends on the severity of the process, the location of the abscess and the severity of intoxication syndrome. In some cases, the symptoms of amoebic colitis come to the fore, against which liver damage develops. Clinical manifestations of the disease can occur both in a few days and months / years from the moment of infection. The acute course of the disease is characterized by an increase in body temperature at first to subfebrile, and after the addition of a secondary infection − to febrile values, pronounced weakness, profuse sweating, nausea, vomiting, decreased appetite, sharp weight loss, icteric sclera and skin.
At the onset of the disease, there is a dull, aching pain and a feeling of heaviness in the right half of the abdomen. As the size of the liver increases, the intensity and frequency of pain attacks increases, which gradually turn into acute pain, which subsides when the body position changes. With an abscess of the right lobe of the organ, the pain is localized in the area of the right hypochondrium and radiates into the right shoulder, shoulder blade, right back and neck. When the abscess is located in the left lobe, the pain syndrome occurs in the epigastric zone and gives to the left shoulder blade, the umbilical and left lateral abdominal regions.
One of the main signs of an amoebic abscess is hepatomegaly. This syndrome is observed with large abscess sizes. During physical examination, the liver is palpated and protrudes from under the edge of the costal arch by 3-6 cm, and with the huge size of the abscess, the organ may protrude in the area of the right hypochondrium. Hepatomegaly leads to compression of nearby organs (intestines, diaphragm), which can cause constipation, increased gas formation, difficulty breathing, shortness of breath. The chronic form of amoebic abscess is characterized by slight hyperthermia, which can persist for a long time (weeks, months), weakness and malaise.
The most dangerous complications are associated with a violation of the integrity of the shell of the amoebic abscess. When the abscess breaks into the abdominal cavity, peritonitis develops, amoebic empyema of the pleura develops into the pleural cavity. Infection entering the bloodstream leads to sepsis, infectious and toxic shock. When pathogenic microorganisms enter the lung tissue, pneumonia, lung abscess, hepatobronchial fistula occur. The entry of parasites into the pericardial cavity is complicated by the development of compressive pericarditis, which can cause cardiac arrhythmia, heart failure and cardiac tamponade. As a result of hematogenic dissemination of the pathogen, the formation of brain abscesses is possible.
Due to the long asymptomatic period and the frequent absence of specific manifestations, the verification of the diagnosis of amoebic liver abscess can cause significant difficulties. Often the disease is detected in the late stages with the development of complications. If pathology is suspected , the following examinations are prescribed:
- Doctor’s examination. Epidemiological history plays an important role in questioning (staying in hot countries, drinking water from untested sources, unwashed fruits and vegetables). During palpation of the abdomen, a specialist (gastroenterologist, abdominal surgeon, infectious disease specialist) pays attention to the enlarged borders of the liver and pain in the hypochondrium on the right.
- Ultrasound of the liver. Ultrasound examination allows to determine the localization, size and structure of the amoebic abscess. The study visualizes a rounded hypoechoic subcapsular formation in the hepatic parenchyma with heterogeneous contents.
- Laboratory diagnostics. In the general blood test, leukocytosis, acceleration of ESR is noted, in the biochemical analysis – an increase in the level of ALT, AST, alkaline phosphatase, bilirubin, total protein. To identify the tissue form of the pathogen, a stool examination is prescribed. Serological tests (RGA, RNIF, IEF, RSC, etc.) are carried out to determine specific antibodies in blood serum.
In difficult and controversial situations, liver MSCT is performed for a more detailed study of the structure of the organ. Differential diagnosis of the disease is carried out with abscesses of other etiology (bacterial, tuberculous, echinococcal, etc.), benign and malignant neoplasms of the liver.
Treatment for amoebic liver abscess
The treatment of pathology is aimed at suppressing the tissue forms of parasites and stopping the purulent process. All patients with suspected amoebic abscess are subject to hospitalization in the specialized department. The basis of conservative therapy is the combined administration of antiprotozoal, antimicrobial, and antibacterial drugs. Along with etiotropic treatment, detoxification and symptomatic therapy with anti-inflammatory, painkillers are carried out.
For severe comorbid patients who did not respond to the initial therapeutic course, fine-needle aspiration of the abscess contents is performed under ultrasound control in order to take material for examination and rehabilitation of the focus. After removing the contents, solutions of antibiotics or antiseptics are injected into the cavity. Open surgical intervention is performed when conservative therapy is ineffective for 2-3 days, with multiple and huge ulcers. In this case, an autopsy, drainage, and thorough treatment of the cavity with an antiseptic solution are performed, after which the abdominal cavity is sanitized and the wound is sutured.
Prognosis and prevention
The prognosis of the disease depends on the size of the amoebic abscess and the presence of complications. With timely diagnosis and competent treatment, the prognosis is favorable. The development of complications can lead to severe life-threatening consequences up to a fatal outcome (20% for pulmonary complications, 40-70% for cardiac complications). Preventive measures are aimed at providing the population with high-quality drinking water, compliance with the rules of personal hygiene (washing hands, vegetables and fruits). Early detection of patients and carriers of infection, their treatment and prevention of infection of healthy people is of great importance. After recovery, patients are subject to medical supervision for a year. Medical control consists in quarterly laboratory tests (stool analysis, serological reactions).
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