Overview.
Amebic liver abscess is formed due to the lysed tissue amebic trophozoites entering the liver from the intestinal lesion through the bloodstream and causing necrosis of the liver, which is actually a complication of amebic colitis, but can also exist alone without amebic colitis. Prolonged fever, right upper abdominal or right lower chest pain, generalized exertion and liver enlargement and pressure, blood leukocytosis, etc. are the main clinical manifestations, and they are prone to lead to chest complications. The ileocecal and ascending colon are the favorable sites for amebic colitis, and the protozoa in this area can return to the right lobe of the liver with the superior mesenteric vein, so the right lobe of the liver accounts for the vast majority of abscesses.
Questions you may be concerned about
What is the difference between an amebic liver abscess and a liver cyst?
Amebic liver abscess and liver cyst are significantly different in pathogenesis, typical symptoms, and treatment.
1. Amebic liver abscess is a complication of amebic enteropathy, which is a purulent infection in the liver.
Typical symptoms are fever and pain in the liver area, mostly in the afternoon fever, body temperature reaches the peak in the evening, body temperature drops at night may be accompanied by night sweats. The pain in the liver area is persistent and dull, and is often worse at night.
Treatment is based on anti-amoebic therapy and anti-infection therapy, and if necessary, surgical puncture and drainage of pus or surgical resection of the lesion.
2. Liver cysts are mostly benign lesions caused by congenital factors.
When the cysts are small, they may be asymptomatic, and when they are large, they may have symptoms such as epigastric mass and abdominal pain.
Asymptomatic patients can be left untreated with regular checkups. Large cysts need to be surgically removed, and in the case of cysts caused by parasites, the parasites need to be removed and the residual cavity eliminated.
Regardless of amebic liver abscess or liver cyst, patients should seek timely medical examination to clarify the condition as soon as possible, and be treated under the guidance of the doctor to avoid progression of the disease.
Etiology
Ameba is divided into two strains, Disperanea amoeba and lysogenous amoeba, of which lysogenous amoeba is pathogenic and is the pathogen causing amoebic liver abscess. Lysosomal amoeba has two phases: trophozoite and encapsulated, and trophozoite used to be divided into small trophozoite and large trophozoite, and the former parasitized in the intestinal lumen, which is called intestinal luminal commensal-type trophozoite; under the influence of certain factors, it invades the intestinal wall, and phagocytosis of erythrocytes transforms into a large trophozoite, which is called tissue-type trophozoite, and it is the causative morphology for amoebic liver abscesses.
Symptoms.
It is related to the course of the disease, the size and location of the abscess, and the presence or absence of complications. Most of the slow onset, with irregular fever, night sweats and other symptoms, fever with intermittent or flaccid type, with complications, the body temperature often reaches 39 ℃ or more, and can be bimodal fever. Most of the body temperature rises in the afternoon and reaches the peak in the evening, accompanied by night sweats at night when the fever subsides, and fever with chills is often combined with bacterial infections. Loss of appetite, abdominal distension, nausea, vomiting, diarrhea, dysentery and other symptoms, pain in the liver area is an important symptom of the disease, which is a persistent dull ache, and it is intensified by deep breathing and change of body position, and the pain is often more obvious at night. Abscess at the top of the right lobe can stimulate the right diaphragm, causing right shoulder pain or compressing the right lower lung to cause pneumonia or pleurisy signs, such as shortness of breath, coughing, the lung base compressing the right lower lung to cause pneumonia or pleurisy signs, elevated turbidity boundaries of the lung base, wet rales detected at the lung base, pleural friction in the abdomen, and so on. When the abscess is located in the lower part of the liver, it can cause right upper abdominal pain and right lumbar pain, and some patients have fullness in the right lower chest or right upper abdomen, or masses are detected, accompanied by compression pain, and rarely there are left lobe liver abscesses. Patients have mid-upper or left-upper abdominal pain radiating to the left shoulder, subxiphoid liver abscess or fullness in the mid or left upper abdomen, tenderness, muscle tension and tenderness to percussion in the hepatic region. The liver tends to be diffusely enlarged, with marked limited pressure and tenderness to percussion in the area where the lesion is located, and the lower edge of the liver is bluntly rounded, with a sense of fullness and a medium-firm texture. In some patients, there is a limited fluctuating sensation in the liver area. Jaundice is rare and mostly mild, with a higher incidence of jaundice in multiple abscesses.
Chronic disease is in a state of failure, with wasting, anemia, and nutritional edema, and fever is counterintuitive. Some patients with advanced stage have enlarged liver, firm texture and localized elevation, which can be easily mistaken for hepatocellular carcinoma.
Examination
1. Blood test
In acute stage, the total number of leukocytes is moderately increased, with about 80% of neutrophils, more when there is secondary infection. When the course of the disease is longer, the white blood cell count is mostly close to normal or reduced, anemia is more obvious, and the blood sedimentation rate increases rapidly.
2. Stool examination
A small number of patients can be detected with histolytic amoeba.
3. Liver function tests
Alkaline phosphatase is the most common, cholesterol and albumin are mostly reduced, and other indicators are basically normal.
4. Serologic examination
The antibody positivity rate can be more than 90%. Negative cases can basically exclude the disease.
5. Liver imaging
B-mode ultrasonography has high sensitivity, but it is difficult to distinguish it from other fluid lesions and requires dynamic observation. The site where the abscess is located can show the liquid plane which is basically consistent with the size of the abscess, or can be localized by puncture or surgical drainage, and the progress of the abscess cavity can be observed by repeated exploration.
CT, hepatic arteriography, radionuclide liver scanning, magnetic resonance can show intrahepatic space-occupying lesions, which is helpful in differentiating amebic liver disease from hepatocellular carcinoma and liver cysts. Among them, CT is particularly convenient, which shows round or ovoid low-density foci with poorly defined margins on CT, and the wall ring of the abscess is enhanced after enhancement, which is of great value for diagnosis if there is gas present in it.
X-ray examination commonly shows elevation of the right diaphragm, limitation of movement, pleural reaction or effusion, and cloudy shadows at the base of the lungs. In left lobe liver abscess, barium meal fluoroscopy of the gastrointestinal tract shows compression of the lesser curvature of the stomach or displacement of the duodenum, and lateral views show anteromedial elevation of the right anterior ribs resulting in loss of the cardiophrenic angle or anterior diaphragmatic angle. Occasionally, irregular translucent fluid-gas shadows in the hepatic region are seen on plain films, which are quite characteristic.
Diagnosis
The basic points of clinical diagnosis of hepatomegaly are: (1) right upper abdominal pain, fever, liver enlargement and tenderness; (2) X-ray examination of the right diaphragm elevation and decreased movement; (3) ultrasonography shows a fluid plane in the hepatic region. If typical pus is obtained by hepatic puncture, or amoebic trophozoites are found in the pus, or there is a favorable effect on specific anti-amoebic drug therapy, the diagnosis of amoebic liver abscess can be confirmed.
Differential diagnosis
The disease should be differentiated from the following diseases:
1. Primary hepatocellular carcinoma
Clinical manifestations such as fever, emaciation, right upper abdominal pain and hepatomegaly resemble amoebic liver abscess, but the latter is often characterized by higher fever, more severe liver pain, and the cancerous liver is harder in texture and has nodules. Measurement of alpha-fetoprotein, B-type ultrasonography, abdominal CT, radionuclide liver scanning, selective hepatic arteriography, magnetic resonance imaging and other investigations can obviously diagnose the disease, and liver puncture and anti-amoebic drug treatment test can help to differentiate the disease.
2. Bacterial liver abscess
Bacterial liver abscess often occurs after sepsis or abdominal septic disorders, with acute onset and significant toxemia symptoms, such as chills, high fever, shock, jaundice, etc. The enlargement is not significant, and the local pressure is painful. The enlargement is not significant, the local pressure and pain is mild, and there is usually no localized elevation, and the abscesses are mostly small and multiple. The pus is small, yellowish-white, bacterial culture may obtain positive results, and suppurative lesions can be seen on histopathologic examination of the liver. The white blood cell count, especially neutrophils, is significantly increased, and bacterial culture can obtain positive results. Antibiotic treatment is effective, easy to relapse.
3. Schistosomiasis
In schistosomiasis endemic areas, it is easy to misdiagnose hepatic amoebiasis as acute schistosomiasis. Both have fever, diarrhea, hepatomegaly and other manifestations, but the latter liver pain is milder, splenomegaly is more significant, blood eosinophils increased significantly, sigmoidoscopy, worm egg soluble antigen test can help identify.
4. Cholecystitis
The onset of the disease is acute, with paroxysmal aggravation of right upper abdominal pain, and there is often a history of recurrent attacks. Jaundice is common and deep, hepatomegaly is not obvious, pressure pain in gallbladder area is obvious, cholangiography and duodenal drainage can be done to distinguish.
5. Liver cyst
Usually it is difficult to identify, but in the case of chronic amebic liver abscess without clinically obvious inflammatory manifestations, or liver cysts with infection, careful identification is also needed. Ultrasonography and characterization of the pus obtained by puncture can help in the differentiation.
Complications
The main complications are secondary bacterial infection and abscess breakthrough to the surrounding tissues. In secondary bacterial infection, chills and high fever are more obvious, toxemia is aggravated, the total number of blood leukocytes and neutrophils are significantly increased, the pus is yellowish-green or has a foul smell, and there are a large number of pus cells on microscopic examination, but the positive rate of bacterial culture is not high. Amebic liver abscesses penetrate to the surrounding organs, such as through the diaphragm to form an abscessed chest or lung abscess, penetrate to the bronchus to cause pleural-pulmonary-bronchial fistula, penetrate to the pericardium or abdominal cavity to cause pericarditis or peritonitis, and penetrate to the stomach, large intestine, inferior vena cava, common bile duct, and the right renal pelvis, resulting in amebiasis of various organs. The prognosis is mostly poor, except for penetration into the gastrointestinal tract or formation of hepatic-bronchial fistula.
Treatment
1. Internal medicine treatment
(1) Anti-amoebic treatment The main choice is to use tissue amoebicidal drugs, supplemented by intestinal amoebicidal drugs to cure. At present, most preferred metronidazole, the cure rate is very high. In uncomplicated patients, the clinical conditions such as liver pain and fever improved significantly within 72 hours after taking the drug, the body temperature subsided within 6 to 9 days, hepatomegaly, tenderness, leukocytosis, etc. recovered about 2 weeks after the treatment, and absorption of pus cavity was as late as about 4 months.
(2) Hepatic puncture and drainage Early treatment with effective medication, many liver abscesses no longer require puncture. For the appropriate drug treatment for 5-7 days, the clinical condition has no obvious improvement, or the liver localized elevation is obvious, the pressure pain is obvious, the diameter of the abscess is >6cm, and there is a danger of perforation, the use of puncture drainage. Puncture is best carried out after 2-4 days of anti-amoebic drug treatment, and the site of puncture is mostly chosen as the 8th or 9th intercostal space of the right anterior axillary line, or the 9th or 10th intercostal space of the right middle axillary line, or the place where hepatic bulge and tenderness are the most obvious, and it is best to carry out the procedure under the localization of ultrasonic exploration. The number of puncture depends on the needs of the disease and silence, each puncture should try to pump the pus, the amount of pus in more than 200ml often need to be repeated in 3-5 days after the aspiration. If the pus cavity is large, the recovery can be accelerated by suction. In recent years, interventional therapy, guided by a needle for continuous closed drainage, can avoid repeated puncture, secondary infection of the shortcomings of the conditions used.
(3) Antibiotic treatment When there is mixed infection, appropriate antibiotics should be applied systemically depending on the type of bacteria.
2. Surgical treatment
Surgical drainage of liver abscess is generally less than 5%. The indications are: ① anti-amoebic drug treatment and puncture drainage failure; ② abscess location is special, close to the hepatic portal, large blood vessels or the location is too deep (> 8cm), puncture easy to injure the neighboring organs; ③ abscess penetration into the abdominal cavity or neighboring viscera, and drainage is not smooth; ④ secondary bacterial infections in the abscess, the medication can not be controlled; ⑤ multiple abscesses, so that the puncture and drainage of the difficult or failed; ⑥ left lobe liver abscess, easy to perforate to the pericardium, easy to penetrate the pericardium, the medication can not control; ⑥ left lobe liver abscess If the left lobe liver abscess is easy to perforate to the pericardium and the puncture is easy to contaminate the abdominal cavity, surgery should also be considered.
The criteria for healing of liver abscess are inconsistent, and clinical healing is generally recognized by the disappearance of symptoms and signs. Most of the filling defects of liver abscess are completely absorbed within 6 months, and a few of them may last up to 1 year, and those with large lesions may have residual hepatic cysts. Blood sedimentation can also be used as a reference indicator.
Prevention
The disease mainly enters the human intestinal tract through the contamination of water, food and vegetables by amoeba protozoa, which then invades the liver and causes abscesses. Therefore, the key to prevent this disease is to pay attention to dietary hygiene and prevent the disease from entering through the mouth.