Amoebic liver abscess

Introduction to amoebic liver abscess Amoebic liver abscess (amebicliverabsces) is a complication of amoebic colitis due to the formation of necrosis of the liver through the blood flow of the amebic trophozoite into the liver from the intestinal lesion. Long-term fever, right upper abdomen or lower right chest pain, systemic consumption and hepatomegaly tenderness, leukocytosis, etc. are the main clinical manifestations, and easily lead to chest complications. The ileocecal and ascending colon are the predilection sites of amoebic colitis, where the protozoa can return to the right lobe of the liver with the superior mesenteric vein, and the right lobe of the liver is larger than the left lobe, and there is more blood return. Therefore, clinically seen In patients, more than 90% of abscesses are in the right lobe, and more at the top. basic knowledge The proportion of illness: 0.003% Susceptible people: no specific crowd Mode of infection: non-infectious Complications: lung abscess peritonitis pericarditis

Etiology of amoebic liver abscess

(1) Causes of the disease

The E. histolytica has two phases of trophozoites and cysts. The trophozoites have been divided into small trophozoites and large trophozoites. The former is parasitic in the intestinal lumen, which is called the intestinal commensal trophozoite. Under the influence, it can invade the intestinal wall, and the phagocytic red blood cells are transformed into the latter, which is called tissue trophozoite. In recent years, molecular taxonomic studies have confirmed that the genotypes and phenotypes of the two types of insect strains have distinct specificities. In 1993, the World Health Organization officially named the non-pathogenic strain Entaoeba dispar based on its isoenzyme spectrum, the apparent difference between membrane antigen and virulence protein and coding gene. The pathogenic strain is still called Entamoeba histolytica. Therefore, most of the trophozoites that exist in the intestinal lumen are considered to be the trophozoites of the Despana amoeba, which are intestine commensal organisms and do not invade. The intestinal wall, and the trophozoites of the amoeba in the lytic tissue, regardless of their size, are invasive and can phagocytose red blood cells at any time. Therefore, the amebic omnivorous trophozoites that phagocytose red blood cells or do not phagocytose red blood cells are called nourishment. Body, nourishment By fresh mucous stool or liquid liver abscess are lively active, 5m / s, to binary fission proliferation, morphological changes is large.

When it is in the tissues of symptomatic patients, it often contains red blood cells, which are usually 20-40 m or even 50 m, but in the non-diarrhea feces of the intestinal cavity or in the culture medium, the size is 10-30 m, excluding Red blood cells, nourish the body, the external matter boundary is very obvious. With a single directed pseudopod movement, there is a vesicular nucleus in the endoplasm, which is spherical, with a diameter of 4-7 m. There is a single layer uniformly distributed at the edge of the nuclear membrane. Staining plasmid (chromatin granule), small nucleolus (only 0.5m), often in the middle, surrounded by a filamentous structure, cystic trophozoites formed in the intestine, but not in the organs outside the intestine or outside In the intestinal lumen, the trophozoite gradually shrinks, stops the activity, becomes a pre-encapsulated cystic stage, and later becomes a nuclear capsule, and undergoes two-divided hyperplasia, which develops into a mature capsule of four cores with a diameter of 10~ 16m, wall thickness 125-150nm, the morphology of the amoeba trophozoite in the tissue, observed by scanning electron microscopy or fluoroscopy, the cell membrane thickness is about 10nm, the outer skin is a layer of fluffy glycocalyx, cytoplasm Contains countless glycogen Granules and helically arranged ribosomes, no typical mitochondria, rough endoplasmic reticulum and Golgi complex. There are many filamentous protrusions on the surface of the trophozoite, with circular holes of 0.2-0.4 m in diameter, and microcells. Related to micropinocytosis, there are no such pores in the pseudopod and micro-drinking nozzles, which is one of the characteristics of the amoeba trophozoites in the lysate.

The in vitro culture of E. histolytica has entered monoxenic culture from xenic culture, and has been developed into axenic cultivation and clonal culture in soft agar medium. The success of biological culture has provided the conditions for in-depth study of amoeba, and solved the problem of preparation of pure antigen. The development of amoebic liver abscess is slow, and it is longer after intestinal amebiasis or amoebic infection. During the occult period, overeating can cause intestinal inflammation, and it is easy to make amoeba infection into activity; alcoholism and other conditions sufficient to reduce the body's resistance can cause the cause of liver abscess, re-infection of amoeba It can stimulate the existing infection and cause liver abscess; the application of adrenal cortex hormone can also induce the occurrence of liver abscess.

(two) pathogenesis

In the colon ulcer, the amoebic trophozoite enters the portal system through its invasive force and reaches the liver; but it can also directly invade the liver through the intestinal wall or reach the liver through the lymphatic system. Most protozoa are destroyed after reaching the liver, only a few can be eliminated. Survival and reproduction in the liver, amoebic trophozoites in the portal vein of the liver due to embolism, dissolution and division, causing local liquefaction necrosis and the formation of abscesses, from the invasion of protozoa to the formation of abscess, on average takes more than 1 month, The location of the abscess is indeterminate. It is more common in large individuals. About 80% is located in the right lobe of the liver, especially in the top of the right lobe. The blood received from the right lobe is due to the cecum and ascending colon of the main lesion of the intestinal amoeba. Because the protozoa spread through the portal vein, early multiple small abscesses are more common, and then merge with each other to form a single large abscess. The center of the abscess is a large necrotic area, and the pus is liquefied liver tissue, which is chocolate-like. Viscous or thin, with livery smell, liver cells containing lysis and necrosis, red blood cells, white blood cells, fat, summer-ray crystals and residual tissue, trophozoites Gathered in the wall of the abscess, about 1/3 of the cases can find trophozoites in the pus, but no cysts have been found. The abscess can be enlarged and gradually superficialized, so that it can be worn to the adjacent body cavity or organ. Chronic abscess can cause bacterial secondary infections, such as Escherichia coli, Staphylococcus, Proteus, Aerobacteria and Alcaligenes, etc. After bacterial infection, the pus loses its typical characteristics, yellow or yellow-green, smelly, and There are a large number of pus cells, and clinical manifestations of toxemia can occur.

Amoebic liver abscess prevention

Pay attention to personal hygiene and food hygiene. Wash hands before and after meals, drink boiling water, raw vegetables and fruits must be cleaned and properly disinfected, such as with vinegar or potassium permanganate. Strengthen physical exercise, improve diet and enhance the body's ability to resist disease. Patients with amoebic dysentery have been found to be treated as soon as possible, taking anti-insect drugs, such as metronidazole and chlorpyrifos hydrochloride, to prevent the occurrence of amebic liver abscess. Chinese medicine Brucea javanica and Pulsatilla chinensis also have preventive and therapeutic effects on acute and chronic amebic bowel disease.

Amoebic liver abscess complications Complications lung abscess peritonitis pericarditis

The main complication of amoebic liver abscess is secondary bacterial infection and abscess to the surrounding tissue, secondary bacterial infection, chills, high fever, increased toxemia, total white blood cells and neutrophils, pus The liquid is yellow-green, or smelly. There are a lot of pus cells in the microscopic examination, but the positive rate of bacterial culture is not high. The amoebic liver abscess is pierced to the surrounding organs, such as through the diaphragm to form empyema or lung abscess. To the bronchus caused by pleural-pulmonary-bronchial spasm, piercing into the pericardium or abdominal cavity causing pericarditis or peritonitis, piercing the stomach, large intestine, inferior vena cava, common bile duct, right renal pelvis, etc., causing the amoeba of various organs In addition to wearing the gastrointestinal tract or forming a liver-bronchial spasm, the prognosis is mostly poor.

Amoebic liver abscess symptoms Common symptoms Fecal pus and blood low fever fever liver metastasis liver pain fatigue low heat fatigue relaxation heat

The development of this disease is generally slow, acute amebic hepatitis is relatively short-lived, if not treated in time, followed by a longer period of chronic phase, its incidence can be several weeks to several years after the onset of intestinal amoeba, and even It has been reported for 30 years after the amoebic liver abscess. In the past, about 60% of the patients had pus and bloody diseases.

1. Acute hepatitis in the process of intestinal amoeba, pain in the liver area, liver enlargement, tenderness, elevated body temperature (body temperature lasts at 38 ~ 39 ° C), pulse rate and a lot of sweating and other symptoms, at this time If treated promptly and correctly, inflammation can be controlled to prevent abscess formation.

2. The clinical manifestations of liver abscess depends on the size, location, length of disease and complications of the abscess, but most patients have a slow onset and a longer course of disease. During this period, the main manifestations are fever, pain in the liver area, and hepatomegaly. Great.

(1) fever: most of the onset is slow, persistent fever, body temperature is 38 ~ 39 ° C, often with relaxation or intermittent heat; chronic liver abscess body temperature can be normal or only low fever; such as secondary bacterial infection or other concurrent When the disease, body temperature can be as high as 40 ° C or more, often accompanied by chills or chills; body temperature is mostly low in the morning, rising in the afternoon, patients with loss of appetite, abdominal distension, nausea, vomiting, and even diarrhea, dysentery and other symptoms; weight loss, weakness and weakness It is also common for weight loss, lack of energy, and anemia.

(2) Pain in the liver area: persistent pain in the liver area, occasional tingling or severe pain. The pain may be aggravated by deep breathing, coughing or body position changes. For example, the abscess is located at the top of the right ankle, and the pain can be radiated to the right scapula or right waist. Back, etc.; can also cause right lower pneumonia and pleural effusion due to compression or inflammation of the right diaphragm and right lower lung. In addition to fever and pain, the patient has shortness of breath, cough and wet sound of the lungs.

(3) local edema and tenderness: larger abscess can appear right lower chest, upper abdomen bulging, intercostal fullness, local skin edema is bright, rib space can be widened, local tenderness or liver area sputum pain is obvious, right upper abdomen There may be tenderness and muscle tension, sometimes with a swollen liver or lump.

(4) hepatomegaly: the liver is often diffusely enlarged, and the lesions have obvious localized tenderness and snoring pain. The swollen liver is squatting under the right costal margin, and the lower edge of the liver is blunt and full. In the quality, the tenderness is obvious, and the abdominal muscles are often accompanied by tension. Some patients may have pleural effusion on the right side.

(5) Chronic cases: Chronic cases can be delayed for several months or even 1-2 years. Patients are weight loss, anemia, dystrophic edema and even chest and ascites; upper abdomen can be swollen and swollen and hard, which is easily misdiagnosed as liver cancer. If there is no secondary bacterial infection, the fever is not obvious.

Adult males with persistent or intermittent fever, poor appetite, weak constitution, and enlarged liver, and those with tenderness should be suspected of having a liver abscess, such as the above phenomenon occurring in the acute disease of amoebic dysentery During the period, or the patient has a history of dysentery, the diagnosis of amebic liver abscess can be initially established. Of course, the failure to recall the history of dysentery in the past does not negate the diagnosis. The clinical manifestations of amebic liver abscess are complicated, and the misdiagnosis rate is higher. High, in order to confirm the diagnosis, it is necessary to combine the symptoms, signs and various indicators to comprehensive analysis.

Amoebic liver abscess examination

[Laboratory Inspection]

1. The total number of white blood cells in the blood examination increased in the early stage [(13~16)×109/L], and often decreased to below normal in the later stage, the neutrophils were about 80%, the secondary infection was higher, and the hemoglobin was decreased. ESR can increase.

2. Fecal and duodenal juice examination A few patients with fecal matter can be found in the tissue of the amoeba, duodenal drainage fluid can also find trophozoites in the tuberculosis.

3. Liver function tests Most of the normal range of ALT and other items, but the serum cholinesterase activity is more prominent.

4. Serological examination using amoeba pure culture antigen for serological reaction, its specificity is very high, such as indirect hemagglutination test, indirect fluorescent antibody test and ELISA test, the positive rate can reach 95% ~ 100%, thus Miba liver abscess has a greater diagnostic value, and negative patients can basically rule out the disease.

5. For gene detection, the molecular weight of amoeba in the tissue is 30×103 protein-encoding gene primer, and the gene fragment can be detected from the pus by PCR method, and the sensitivity and specificity are both 100%.

[Other inspections]

1. Ultrasound examination B-mode ultrasound imaging diagnosis accuracy rate of more than 90%, showing liver area liquid dark area, while understanding the size, extent, number of abscess, help guide the qualitative diagnosis and treatment of puncture.

2. X-ray examination of right diaphragmatic muscle elevation, limited movement, local uplift; sometimes visible pleural reaction or effusion, right lower pneumonia or discoid lung atelectasis; occasionally visible flat film showed a gas-liquid surface in the abscess; liver The irregular light-transparent liquid gas shadow has special diagnostic significance, and the contrast agent can be injected to display the size of the abscess.

3. The area of CT liver abscess is uneven or uniform low-density area. After the contrast agent is strengthened, the annular density increases with the shadow of the abscess. There is a gas-liquid surface in the abscess. The density of the cyst is similar to that of the abscess, but the edge is smooth and there is no periphery. Congestion zone; CT value of liver tumor is 35 ~ 50Hu, significantly higher than liver abscess.

4. Radionuclide scanning shows that there is a space-occupying lesion in the liver, that is, a radioactive defect area, but an abscess or multiple small abscess with a diameter of less than 2 cm is easily missed or misdiagnosed as a metastatic tumor or cyst, so it is only helpful for localization diagnosis.

5. Diagnostic liver puncture can extract chocolate-like brown odorless, sticky pus, amebic trophozoites may be found in the centrifuged sediment, but because of the presence of amoebic on the wall of the abscess, the positive rate is low. If the pus is added to 10 units of streptokinase per ml, and the incubation is carried out at 37 ° C for 30 min, the positive rate can be increased.

Diagnosis and differentiation of amebic liver abscess

diagnosis

1 right upper quadrant pain, fever, liver enlargement and tenderness;

2X line examination of the right iliac muscle elevation, exercise reduced;

3 Ultrasound examination shows the liver leveling section. If the liver puncture obtains typical pus, or the amoebic trophozoite is found in the pus, or the specific anti-amebic drug treatment has a good effect, the amoeba can be diagnosed. Liver abscess.

With the disease course, abscess in small and parts, with or without complications, mostly slowed up, there are irregular fever, night sweats and other symptoms, fever is mostly intermittent or relaxation type, and the body temperature often reaches 39 °C when there is a complication, and It can be bimodal fever, body temperature rises most in the afternoon, peaks in the evening, accompanied by sweat at night, and the middle layer often has loss of appetite, abdominal distension, nausea, vomiting, diarrhea, dysentery and other symptoms. Liver pain is important for this disease. Symptoms, learning is persistent dull pain, deep breathing and changes in body position, nighttime pain is often more obvious, right lobe abscess can stimulate the right diaphragm, causing right shoulder pain, or oppression of the right lower lung causes pneumonia or pleurisy signs, such as Shortness of breath, cough, lungs forced to the right lower lung caused by signs of pneumonia or pleurisy, such as shortness of breath, cough, elevated lunar sounds in the lungs, smell of wet rales at the bottom of the lungs, pleural friction in the ankle, etc., when the abscess is located in the lower part of the liver Caused right upper quadrant pain and right back pain, some patients with right lower chest or right upper abdomen full, or lumps and masses, accompanied by tenderness, left lobe liver abscess accounted for about 10%, patients with upper abdomen or left upper abdominal pain, radiation to the left shoulder, sword Burst Hepatomegaly or middle, full left abdomen fullness, tenderness, muscle tension and pain in the liver area, the liver is often diffusely enlarged, the site of the lesion has obvious localized tenderness and slap pain, the lower edge of the liver is obtuse, full of feeling In the middle of the disease, some patients have localized fluctuations in the liver area. The jaundice is rare and mild, and the incidence of jaundice in multiple abscesses is higher.

Chronic cases are in a state of exhaustion, weight loss, anemia, nutritional edema, and fever is not obvious. Some patients with advanced hepatomegaly are strong and strong, and local uplift is easy to be mistaken for liver cancer.

Differential diagnosis

1. Primary liver cancer generally has no obvious fever, rapid liver, hard and uneven surface, alpha-fetoprotein positive, B-mode ultrasound, CT scan, hepatic artery angiography, magnetic resonance examination and liver biopsy have diagnostic value .

2. Bacterial liver abscess.

3. Underarm abscess often occurs in abdominal purulent infections, such as perforation of ulcer disease, appendicitis perforation or abdominal surgery, the disease is characterized by systemic symptoms, but the abdominal signs are light; X-ray examination of the transverse sputum is generally elevated and limited activity However, there is no localized bulge, and there is a gas-liquid surface under the armpit; B-ultrasound suggests a submerged dark area and an intra-hepatic no-liquid area; the radionuclide liver scan does not show a defect in the liver; when MRI is performed, The coronal section can show a fluid zone in the sacral and hepatic spaces, while the liver is normal.

4. The difference between localized empyema is that the disease has a history of lung infection or chest injury. The speech or tactile tremor is reduced or disappeared. The percussion of the affected part is a real sound, the liver does not increase, but it may not shift slightly downward. Tenderness, chest X-ray examination showed that the diaphragm muscles did not rise, chest puncture can extract pus, and can detect the bacteria.

5. Pancreatic abscess The early stage of the disease is acute pancreatitis. In addition to sepsis, there may be pancreatic dysfunction, such as diabetes, feces with undecomposed fat and undigested muscle fibers. The liver is enlarged and light, without touch. Pain, the swelling of the stomach during the pancreatic abscess in front of the lesion, liver scan without abnormalities, if the conditional CT can help locate.

6. Hepatic hydatidosis This disease can be misdiagnosed as bacterial liver abscess. The medical history should be detailed, such as animal husbandry or animal husbandry. The patient should have an abdominal mass and then have sepsis symptoms. X-ray or visible calcified wall. The hydatid skin test was positive.

7. Schistosomiasis in the schistosomiasis endemic area, easy to misdiagnose liver amebiasis as acute schistosomiasis, both have fever, diarrhea, hepatomegaly, etc., but the latter liver pain is lighter, splenomegaly is more significant Eosinophils in blood are significantly increased, large cases are hatched, sigmoidoscopy, and soluble antigen detection of eggs is helpful for identification.

8. Cholecystitis is onset, the upper right abdominal pain is exacerbated, and there is often a history of recurrent episodes. The jaundice is more common and deeper. The hepatomegaly is not significant. The gallbladder area has obvious tenderness. It can be used for gallbladder angiography and duodenal drainage. To be identified.

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