Hepatic echinococcosis

Introduction to hepatic hydatid disease Hepatic hydatidosis, also known as hepatic hydatid disease, is a parasitic disease caused by parasitic larvae of the canine aphid (Echinococcus granulosus) parasitic in the liver. The disease is caused by Echinococcus granulosus (E). .granulosus), caused by E. multilocularis or E. alveolaris. There are two types of hepatic hydatidosis: one is a single atrial hydatid disease caused by Echinococcus granulosus infection (ie, hydatid cyst); the other is multi-atrial or vesicular spine The echinococcosis caused by the ball mites infection, or follicular hepatic hydatidosis, is clinically common in atrial echinococcosis. It is more popular in northwestern China and Inner Mongolia and western Sichuan. basic knowledge The proportion of illness: 0.0003% Susceptible people: no specific population Mode of infection: digestive tract spread Complications: nausea and vomiting, urticaria, cough, abdominal pain, ascites

Causes of hepatic hydatid disease

(1) Causes of the disease

The terminal host of Echinococcus granulosus is mainly dogs, while the intermediate host may be sheep, pigs, horses, cattle and humans. It is more common in sheep, and humans are the intermediate host of hydatid. Liver cyst lesions.

The adult echinococcosis is only a few centimeters long and has a head, a neck, an immature body segment, a mature body segment and a pregnant body segment. This adult is parasitic in the small intestine of the dog, or sucks in the villi. Above, or in the glandular recess, when the pregnancy body segment collapses, the eggs are scattered in the intestine, and the dog feces are discharged and often adhere to the dog's hair. When the person is in contact with the dog, there is The opportunity to accidentally swallow the eggs into the stomach, and hatch into the six-claw in the duodenum, then invade the small intestine wall and enter the portal system. About 70% of the blood that has entered the portal vein is filtered out in the liver. In the liver, cysts with special structure are gradually formed. The remaining larvae can pass through the liver and spread through the right heart in the lungs (15%), muscle, kidney, spleen, bones, eyelids, brain and other tissues. The lesion.

(two) pathogenesis

Echinococcus granulosus first develops into small vacuoles in the liver, that is, the initial hydatid cysts, which gradually grow up to form an inner capsule with a stratum corneum and a germinal layer (ie, the body of the hydatid). The layer is white, soft and elastic translucent film, like a powder skin, and the inner layer is a germinal layer. The germinal cells proliferate and form a hair follicle, and the latter fall off into the cyst fluid to form an ascus, and the ascus can be The sun sac is produced... The sac contains many head knuckles. After the rupture, the anterior segment enters the sac fluid to form a "sac sand". The sac is the seed of the worm. Once it is leaked into the abdominal cavity, it can be planted to form a new secondary worm. Around the hydatid, a fibrous envelope is formed by the proliferation of the host organ, which is the outer capsule. The outer capsule of the chronic diseased patient can be calcified, making it a characteristic expression on the X-ray photograph, and the hydatid cyst is filled with liquid. Clear and transparent, pH 7.8, specific gravity 1.008~1.015, containing traces of protein and inorganic salts, hydatid cysts grow slowly, but continue to increase the liver tissue atrophy caused by compression of surrounding liver tissue, can also oppress the bile duct and cause obstructive jaundice, When the cyst grows outward, it can be pressed Forced adjacent organs and organs to produce corresponding symptoms, such as cysts due to external forces or spontaneous rupture can produce anaphylactic shock and abdominal or thoracic implants, cysts can also break into the biliary tract or gastrointestinal tract with guilt and infection.

The genus Echinococcus is mainly parasitic to the liver and is characterized by:

1 The lesion consists of a large number of tiny vesicles, which are formed by the continuous growth of the vesicles, but no intact stratum corneum, so no internal capsule is formed.

2 The cancer-like infiltration spreads and directly destroys the liver tissue, forming a giant-shaped bubble bulb. The center often undergoes necrosis, liquefaction forms a cavity or calcification, the surrounding tissue shrinks due to compression, and the blood vessel is occluded due to pressure. The surface of the lesion is grayish-white and hard, and there is little bleeding in the incision. The biliary tube is compressed and occluded, and jaundice appears. The bulbous sputum, such as invading the branch of the portal vein, can spread through the liver to form multiple nodules, and the granuloma inflammatory reaction can be induced. Cirrhosis of the liver, cholangiocarcinoma, and spheroidal sputum are divided into massive type, nodular type and mixed type. They are more common in giant pieces. In addition, vesicles can also be transferred to the lungs, brain and liver via the hepatic vein and lymph. Portal lymph nodes, etc.

Hepatic hydatidosis prevention

1. Propaganda about the knowledge of hydatid disease should be widely carried out in animal husbandry areas.

2, develop the habit of washing hands after contact with livestock and before meals, do not eat unwashed cooked food, do not drink raw water.

3. Strengthen the management and quarantine of livestock, immunization work, prevent dog dung from contaminating drinking water and food.

4, can not be used to produce livestock internal organs, especially the internal organs of infected livestock to feed dogs.

5. The dead bodies of sick and dead animals should be buried or burned. Do not dispose of them anywhere, so as to avoid infection after eating.

6, organize pastoral population census, for early diagnosis and early treatment.

Hepatic hydatid complications Complications, nausea and vomiting, urticaria, cough, abdominal pain, ascites

When developing to a certain stage, there may be a feeling of fullness of the upper abdomen, slight pain or compression of the corresponding symptoms caused by adjacent organs. If the mass is pressed against the gastrointestinal tract, there may be upper abdominal discomfort, loss of appetite, nausea, vomiting and bloating. The cyst located at the top of the liver can raise the diaphragm upwards, compressing the lungs and affecting the breathing. The cysts located in the lower part of the liver can compress the biliary tract, causing obstructive jaundice, and the portal vein can produce ascites. More commonly, the patient suffers from various complications. Visiting, such as skin itching due to allergic reactions, urticaria, difficulty breathing, cough, purpura, vomiting, abdominal pain, cystic secondary infection is a very common symptom.

Hepatic hydatid symptoms common symptoms, loss of appetite, splenomegaly, upper abdominal discomfort, purpura, abdominal pain, jaundice, nausea, abdominal distension, ascites

Patients often have a long history of disease and a progressive progression. The age of treatment is the most common in 20 to 40 years old. The initial symptoms are not obvious, and the upper abdominal mass can be noticed by accident. When it reaches a certain stage, there may be a feeling of fullness in the upper abdomen, slight pain or compression of the corresponding symptoms caused by adjacent organs. If the tumor compresses the gastrointestinal tract, it may have upper abdominal discomfort, loss of appetite, nausea, vomiting and bloating. The cyst located at the top of the liver can raise the diaphragm upwards, compressing the lungs and affecting the breathing; the cysts located in the lower part of the liver can compress the biliary tract, causing obstructive jaundice, and the portal vein can produce ascites.

More often, patients see a doctor for various complications. Such as skin allergies due to allergic reactions, urticaria, difficulty breathing, cough, purpura, vomiting, abdominal pain. Secondary infections of cysts are very common symptoms.

Hepatic hydatidosis

[Laboratory Inspection]

1. Complement binding test generally uses sheep or human hydatid cyst fluid as antigen, and the positive rate of hydatid cysts still active in hydatid cysts can reach 70%-90%; hydatid cysts rupture or hydatid cysts after surgery In the short term, because the body absorbs more antigens, the positive rate is higher. The diagnostic value of this method is not as good as the Casoni test, but it is helpful for judging the curative effect. After removing the cyst for 2-6 months, the complement fixation test turns negative. It was still positive after 1 year of surgery, suggesting that there were still hydatid cysts in the body.

2. The normal value of eosinophil count is less than 6%, with an average of 2%. It is elevated in patients with hepatic hydatidosis, usually between 4% and 10%, and a few can reach 20% to 30%. Eosinophils are significant. Elevation is common in cases of cyst rupture, especially intra-abdominal rupture.

3. Enzyme-linked immunosorbent assay (ELISA) and dot immuno-binding assay (DIBA) Both assays are enzyme immunoassays. The positive rates of patients are 100% and 98%, respectively, and the false positive rates are 1.9% and 1.3%, respectively. Individual liver cancer patients may have a false positive reaction.

[Other inspections]

1. Insect skin test (Casoni test) The method is to use the transparent hydatid cyst fluid obtained by surgery, filter the original head sputum, autoclave as an antigen, and dilute with physiological saline (1:1001: 4), take 0.2ml for intradermal injection to form a ridge of about 0.3cm in diameter, and observe the result after 15min. The positive standard is pyel enlargement or blush diameter more than 2cm, such as positive reaction after 6-24h after injection, For delayed response, there is still diagnostic value. The positive rate of hepatic hydatid cyst can reach 90%, the positive rate of hepatic alveolar hydatid disease is higher, and patients with tuberculosis, kala-azar or other ascariasis can have false positive reaction. The hydatid cyst can be necrotic or infected with suppuration can be negative.

2. X-ray examination of the cyst located in the top of the liver sputum can be seen in the diaphragmatic elevation, activity is weak, X-ray film can show the right upper abdomen has a uniform density of uniform edge shadows, can be accompanied by calcification, the latter is diverse, with arcs Shape, thick shell, dense mass or diffuse strips, cysts located in the anterior and posterior liver can be seen gastrointestinal compression.

3. B-ultrasound examination of hepatic hydatid cysts under the B-ultrasound has a variety of sonographic features, manifested as single or multiple circular or elliptical liquid dark areas, clear boundaries with liver tissue, the wall is generally thick, often Above 3mm, the echo of the posterior wall of the capsule is enhanced, and some of the capsule wall is calcified and expresses strong echo. The rear can be accompanied by sound and shadow. The sound in the capsule is good, and most of the points are strong echo floating, and shift with the body position. It is caused by ascospore or echinococcosis. If the mother sac is filled with a large ascus, it is multi-atrial. The capsule has a strong echo band separated into corresponding small sacs. The separation is petal-like, some cysts are degenerated, and the cyst fluid is Absorption, the content of which is transformed into a jelly-like substance. At this time, it appears as a solid mass with irregular echogenic plaque and a small amount of liquid dark area, but the boundary between the mass and the liver tissue is clear, when the cyst squeezes the bile duct or Broken into the bile duct, visible intrahepatic bile duct dilatation, cystic compression of the portal vein can be seen splenomegaly, and may be associated with ascites, secondary infection of the cyst presents the sonographic features of liver abscess.

Hepatic alveolar echinococcosis manifests as a patchy irregular solid mass similar to liver cancer under B-ultrasound, and the liver tissue is unclear, the internal echo is disordered, the intensity is uneven, and there may be a small liquid dark area. .

4. CT examination of liver hydatid cysts usually appear in CT images of different sizes, single or multiple, smooth, round, oval or lobulated low-density lesions, CT density values close to the relative density of water ( 0 ~ 25HU), no enhancement effect, the wall of the capsule is generally thick, sometimes visible arc or ring calcification, the capsule has one of its characteristics, the relative density of the ascus is usually lower than the mother capsule, the existence of multiple ascus The lesions were multi-atrial, and some CT images of hepatic hydatid cysts were classified into 3 types: type A: the ascus was small and round, distributed in the early stage of the development of the mother sac; type B: the ascus was large and irregular, almost occupying the mother sac The whole volume is squeezed into a petal shape, and the ascospore is separated by a thick septum. Type C: a cyst with a longer course of disease, the cystic fluid has a higher CT density value (40-60HU), and has calcification at the edge or inside. A small number of small sacs are located around the mother sac. When the cyst breaks into the bile duct, biliary obstruction such as intrahepatic bile duct dilatation can be seen. After cyst secondary infection, the CT density of the cyst fluid increases, and gas can appear, and edema changes can be seen in the surrounding liver parenchyma.

Hepatic alveolar echinococcosis is characterized by unclear lamellae low-density lesions. Due to its outward bud characteristics, the ascus has a thick serrated bulge at the edge of the lesion, which is more clear after enhanced scanning. One of the changes, there are liquid areas of different sizes in the lesion, so that the whole lesion is in a "map" shape. About 80% to 90% of the cases have calcifications in the lesions, which are irregular plaques, fine granular, knots. Section or ring shape.

5. Magnetic resonance imaging (MRI) examination On the T1-weighted image, the hydatid cyst wall showed a continuous smooth, thin and uniform low-signal annular edge; it was more clearly displayed on the T2-weighted image, which is a characteristic of hepatic hydatid cyst. Change, the contents of the capsule show a low signal on the T1-weighted image, a high signal on the T2-weighted image, a low signal or the like on the proton density image, and if the mother capsule is filled with ascus, the cyst is multi-atrial, in the cyst After a rupture infection, the shape of the wall becomes irregular and the internal signal is not uniform.

6. Radionuclide imaging Hepatic hydatid cysts show a very clear radioactive defect area, while hepatic alveolar hydatid disease is characterized by blurred boundaries and irregular radioactive defect areas.

Diagnosis and identification of hepatic hydatid disease

diagnosis

The patient often has a history of many years, and the course of the disease is progressive. The age of the treatment is 20-40 years old. The initial symptoms are not obvious. It can be found by accident that the upper abdomen mass begins to attract attention. When it reaches a certain stage, the upper abdomen can appear. Fullness, slight pain or compression of the corresponding symptoms caused by adjacent organs, such as a tumor that compresses the gastrointestinal tract, may have upper abdominal discomfort, loss of appetite, nausea, vomiting and bloating, etc. The cyst at the top of the liver can lift the diaphragm High, oppressing the lungs and affecting breathing; cysts located in the lower part of the liver can compress the biliary tract, causing obstructive jaundice, which can produce ascites.

More common cases are patients with various complications, such as skin itching due to allergic reactions, urticaria, difficulty breathing, cough, purpura, vomiting, abdominal pain, secondary infection of cysts is a very common symptom.

Differential diagnosis

1. Hepatic cysts Hepatic hydatid cysts have only 65% of the typical signs of B-ultrasound and CT. In the absence of these typical signs, they need to be differentiated from hepatic cysts. Hepatic cysts are a congenital disease, generally no There is no special discovery in the pastoral life history. The cyst wall is generally thin. It is unclear on B-ultrasound, CT or MRI. There is no cyst in the capsule. Some hepatic cysts are separated inside and are multi-atrial. They should be differentiated from the ascus. .

2. Liver abscess Hepatic hydatid cysts are easily misdiagnosed as liver abscess after bacterial infection. Both of them may have clinical manifestations such as pain in the liver area, fever, and elevated white blood cells. Imaging examinations are sometimes difficult to distinguish and should be combined with epidemics. The history of the diagnosis and differential diagnosis, liver hydatid cysts due to thick and tough outer capsule, the symptoms of systemic poisoning after secondary infection is generally lighter than bacterial liver abscess.

3. The invasive growth and metastasis of hepatic alveolar echinococcosis in primary liver cancer resembles primary liver cancer. The imaging findings are solid masses with unclear intrahepatic boundary and are easily misdiagnosed as primary. In addition to epidemiological history, patients with hepatic alveolar echinococcosis have no history of hepatitis, AFP is negative and Casoni test can be positive, radiographic examination shows calcification in the mass, CT enhanced scan can show vesicles around the mass Signs can generally be distinguished from primary liver cancer.

4. Hepatic cavernous hemangioma Patients with hepatic cavernous hemangioma are mostly in good general condition. The tumor can be filled with contrast agent on the enhanced CT scan. The MRI T2-weighted image shows a uniform high signal, and the radionuclide hepatic blood pool scan can be seen. The lesions are overfilled and generally not difficult to distinguish.

5. Other hepatic hydatid cysts sometimes need to be differentiated from choledochal cyst, Caroli disease, gallbladder effusion, right renal giant cyst, pancreatic cyst, mesenteric cyst, etc. When the complications of liver hydatid cysts occur, the original clinical manifestations are often It is easily covered by complications and is easily misdiagnosed. Detailed diagnosis and differential diagnosis should be made.

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