Echinococcosis of the liver

　　1. Causes of Disease

　　The definitive hosts of the fine-grained echinococcus are mainly dogs, while the intermediate hosts may include sheep, pigs, horses, cattle, and humans, with sheep being the most common. As intermediate hosts of the hydatid cyst, humans exhibit various visceral cystic lesions, primarily in the liver.

　　The adult of the small granular echinococcus is only a few centimeters long, with one head, one neck, an immature somatic segment, a mature somatic segment, and a gravid segment. This adult worm lives in the small intestine of dogs, or attaches to the villi, or exists in the glandular grooves. After the gravid segment collapses, the eggs are scattered in the intestinal lumen, excreted with feces, and often adhere to the dog's fur. When humans come into contact with dogs, there is an opportunity to accidentally ingest the eggs into the stomach, and they hatch into hexacanth larvae in the duodenum, then penetrate the intestinal wall to enter the portal venous system. About 70% of the larvae that have entered the portal venous blood flow are filtered out in the liver and gradually form cysts with special structures within the liver. The remaining larvae can pass through the liver and disperse in the lungs (15%), muscles, kidneys, spleen, bones, orbital, brain, and other tissues, forming similar lesions.

　　2. Pathogenesis

　　Small granular echinococcus first develops into small empty vesicles in the liver, which are the initial hydatid cysts. Later, they gradually grow into an inner cyst with a keratin layer and a germ layer (i.e., the hydatid body). The keratin layer is the outer layer of the inner cyst, a white, soft, and elastic semitransparent membrane resembling tofu skin. The inner layer is the germ layer, formed by the proliferation of germ layer cells inwardly to form germ vesicles. These vesicles fall into the cyst fluid to form daughter cysts, which can produce great-granddaughter cysts……. The daughter cysts contain many scolexes, and upon rupture, the scolexes enter the cyst fluid to form 'cyst sand,' which is the seed of the hydatid. Once it leaks into the abdominal cavity, it can be implanted and generate new secondary hydatids. Around the hydatid, a fibrous capsule is formed by the proliferation of host organ tissue, which is the outer capsule. In long-standing patients, the outer capsule can become calcified, showing a characteristic appearance on X-ray films. The hydatid cyst is filled with fluid, clear and transparent, with a pH of 7.8 and a specific gravity of 1.008-1.015, containing trace amounts of protein and inorganic salts. Hydatid cysts grow slowly, but continued growth can compress surrounding liver tissue, causing atrophy of liver cells, or compress the bile duct, leading to obstructive jaundice.向外生长的囊肿 can compress adjacent tissues and organs, producing corresponding symptoms. If the cyst ruptures due to external force or spontaneously, it can cause an anaphylactic shock and abdominal or thoracic implantation. The cyst can also rupture into the biliary tract or gastrointestinal tract, leading to internal fistula and infection.

　　Cystic echinococcosis mainly resides in the liver, characterized by: ① Lesions are composed of a large number of small vesicles, which are formed by the continuous outward proliferation of the germ layer but lack a complete keratin layer, thus not forming an inner cyst. ② It infiltrates and spreads like cancer, directly destroying liver tissue and forming massive vesicle cysts. The center often undergoes necrosis and liquefaction, forming cavities or calcification. Surrounding tissues atrophy due to compression, and blood vessels become occluded, making the surface of the lesion appear grayish white and hard, with little bleeding upon incision. Obstruction of the bile duct leads to jaundice. Cystic echinococci can invade the portal vein branches and spread within the liver through hematogenous route, forming multiple nodules, causing granulomatous inflammatory response, and may trigger liver cirrhosis or cholangiocellular liver cancer. Cystic echinococci are classified into massive, nodular, and mixed types, with the massive type being more common. In addition, cystic echinococci can also metastasize to the lungs, brain, and portal lymph nodes through the hepatic veins and lymphatic system.

　　一、继发感染

　　约10％～30％的肝包虫囊肿会继发细菌性感染。致病菌主要来自于胆管系统。囊肿在逐渐增大的过程中压迫周围肝组织形成纤维性包膜。肝内小胆管常受压迫并被包入纤维包膜中。这些小胆管可破入囊腔。一般认为约80％的肝包虫囊肿与肝内胆管存在显性或隐性交通瘘，致病菌随胆汁经瘘口入侵囊肿而发生感染。肝包虫囊肿继发感染后的典型三联征包括寒战、高热、肝区持续胀痛和囊肿短期内迅速增大。囊肿的迅速增大使得原来对周围脏器的压迫症状更加明显，如受外力挤压、局部震动或行不正确的穿刺，容易发生破裂。实验室检查表现为白细胞升高，可伴有贫血；B超显示囊壁增厚、囊内回声不均，可见不规则强回声团块；CT扫描时囊液CT密度值升高，囊内可出现气体，并可伴有囊周组织水肿的表现。临床上应注意与肝脓肿相鉴别。

　　二、囊肿破裂

　　2.

　　Firstly, Secondary Infection: What complications can liver echinococcosis easily lead toSecondly, Cyst Rupture: About 10% to 30% of liver hydatid cysts may develop secondary bacterial infections. The pathogenic bacteria mainly come from the biliary system. As the cyst gradually increases in size, it compresses the surrounding liver tissue to form a fibrous capsule. The small intrahepatic bile ducts are often compressed and enclosed in the fibrous capsule. These small bile ducts can breach into the cyst cavity. It is generally believed that about 80% of liver hydatid cysts have overt or covert fistulas with intrahepatic bile ducts, and pathogenic bacteria invade the cyst through the fistulas and cause infection. The typical triad of secondary infection of liver hydatid cysts includes chills, high fever, persistent pain in the liver area, and rapid increase in the size of the cyst in a short period of time. The rapid increase in the size of the cyst makes the original compression symptoms on the surrounding organs more obvious, such as easy to rupture when subjected to external force compression, local vibration, or incorrect puncture. Laboratory examination shows an increase in white blood cells, which may be accompanied by anemia; ultrasound shows thickening of the cyst wall, uneven echo within the cyst, and irregular hyperechoic masses; CT scanning shows an increase in CT density value of the cyst fluid, the presence of gas within the cyst, and the appearance of pericystic tissue edema. Clinically, it should be distinguished from liver abscess.

　　1. Breaching the Biliary Duct: Liver hydatid cysts have a chance to rupture for various reasons, as reported in Chinese literature, it is 12.9%. Cysts can rupture spontaneously, especially after secondary infection, due to the rapid increase in cyst fluid caused by inflammatory stimulation, which increases the intracystic pressure, making the chance of rupture greater. Certain traumatic factors (such as puncture, compression, etc.) can also cause cyst rupture. Cysts at different locations can breach into different areas and cause corresponding clinical symptoms.2. Breaching the Abdominal Cavity: This is the most common complication, occurring in about 5% to 10% of cases, and can breach into extrahepatic bile ducts and gallbladders, but most breach into intrahepatic bile ducts. The main factor for breach into the bile duct is the compression of the bile duct wall by the cyst, causing local necrosis of the latter. When the cyst breaches into the bile duct, it presents with three main symptoms: biliary colic, jaundice, and urticaria, which should be distinguished from cholelithiasis. Obstruction of the bile duct by the contents of the cyst, especially in cases where the original cyst is already infected, can cause acute obstructive suppurative cholangitis.

　　3. Breaching the Thoracic Cavity: Cysts located on the surface of the liver are prone to breach into the abdominal cavity. After rupture, the contents of the cyst (including cyst fluid, daughter cysts, and protoscolices) enter the abdominal cavity, causing sudden abdominal pain and anaphylactic shock, and the abdominal mass may suddenly shrink or disappear. The entry of cyst fluid into the abdominal cavity can cause varying degrees of peritoneal irritation symptoms. If the original cyst communicates with the bile duct, the entry of bile into the abdominal cavity can cause severe cholecystitis. Rupture of an infected cyst into the abdominal cavity can cause diffuse peritonitis. When the inflammation in the abdominal cavity is very obvious, the protoscolices may die, leaving granulomas, but it is more common for the protoscolices to survive and develop into multiple cysts several years later, known as secondary abdominal echinococcosis. Acute abdominal symptoms caused by the rupture of liver hydatid cysts into the abdominal cavity should be distinguished from acute abdominal symptoms caused by other reasons.Hydatid cysts located at the top of the liver diaphragm, especially after secondary infection, can penetrate the diaphragm and break into the pleural cavity, causing acute pleural effusion and allergic reactions, which are more common in the right pleural cavity. When the cyst breaks into the pleural cavity, it is often accompanied by paroxysmal severe cough and cutting-like chest pain. Due to inflammation, adhesions are formed between the cyst, diaphragm, and lung, and the cyst can directly break into the bronchus, forming a cyst-bronchus fistula. If the cyst has communicated with the bile duct, then a bile duct-bronchus fistula is formed. Initially, there may be coughing up blood-tinged froth, and later, sputum containing bile, cyst fluid, proglottids, and fragments of the inner cyst are coughed up. A few patients may experience asphyxia.

　　4. Breaking through the abdominal wall:After secondary infection of the hydatid cysts in the liver, they can adhere to the abdominal wall and break through the abdominal wall to ulcerate, flowing out the cyst fluid and contents to the outside, forming a chronic abdominal wall sinus tract.

　　5. Breaking into the pericardial cavity:Hydatid cysts located in the left lobe of the liver can penetrate the diaphragm and break into the pericardial cavity, causing acute pericardial tamponade.

　　6. Breaking into the hepatic vein:A few hydatid cysts in the liver can break into the hepatic vein, and the contents of the cysts entering the hepatic vein can cause pulmonary artery embolism.

　　1. In pastoral areas, it is necessary to widely carry out publicity on the knowledge of echinococcosis.

　　2. Develop the habit of washing hands after contact with livestock and before meals, do not eat uncleaned and uncooked food, and do not drink unboiled water.

　　3. Strengthen the management and quarantine, as well as immunization work of livestock, to prevent canine feces from contaminating drinking water and food.

　　4. Do not feed uncooked internal organs of livestock, especially those from infected livestock, to dogs.

　　5. The bodies of dead livestock should be buried deeply or incinerated, and should not be discarded on the ground to avoid infection after dogs eat them.

　　6. Organize a general survey of pastoral areas to achieve early diagnosis and early treatment.

　　1. Laboratory examination

　　1. The complement fixation test usually uses the fluid of hydatid cysts from sheep or humans as antigens. The positive rate in patients with active hydatid cysts can reach 70% to 90%; in the short term after the rupture of hydatid cysts or after surgery, due to the human body absorbing more antigens, the positive rate is even higher. This method is less valuable for diagnosis than the Casoni test, but it is helpful in judging the efficacy. The complement fixation test turns negative 2 to 6 months after the cyst is removed. If it remains positive after one year of surgery, it suggests that there may still be hydatid cysts in the body.

　　2. The normal value of eosinophil count is less than 6%, with an average of 2%. It increases during the disease of echinococcosis of the liver, usually between 4% to 10%, and a few may reach 20% to 30%. A significantly increased eosinophil count is often seen in cases of cyst rupture, especially intraperitoneal rupture.

　　3. Enzyme-linked immunosorbent assay (ELISA) and dot immunobinding assay (DIBA) are both enzyme immunoassay methods. The positive rates for patients are 100% and 98%, respectively, with false-positive rates of 1.9% and 1.3%, respectively. Some liver cancer patients may show false-positive reactions.

　　Two, other examinations

　　1. The Casoni test for echinococcosis is a method that uses transparent fluid from the hydatid cyst obtained during surgery, filters out the protoscolex, sterilizes it under high pressure, and uses it as an antigen. It is diluted with physiological saline (1:100 to 1:4) and 0.2ml is injected intradermally to form a skin nodule with a diameter of about 0.3cm. The result is observed after 15 minutes. The positive criterion is that the nodule expands or the erythema diameter exceeds 2cm. If a positive reaction is present 6 to 24 hours after injection, it is called a delayed reaction and still has diagnostic value. The positive rate for liver hydatid cysts can reach 90%, and the positive rate for alveolar echinococcosis is even higher. Patients with tuberculosis, kala-azar, or other tapeworm diseases may have false-positive reactions. A negative reaction may occur after the hydatid cyst necrosis or becomes infected and suppurated.

　　2. X-ray examination shows that when the cyst is located at the top of the liver diaphragm, the diaphragm is elevated and its mobility is reduced. X-ray films can show a uniform density shadow with a neat edge in the upper right abdomen, which may be accompanied by calcification shadows. The latter may have various shapes, such as curved lines, thick shell-like, dense mass-like, or diffused dot-like. When the cyst is located in the anterior lower part of the liver, gastrointestinal compression and displacement can be seen.

　　3. Ultrasound examination of hydatid cysts in the liver shows various sonographic features, manifesting as single or multiple circular or elliptical liquid dark areas, with clear boundaries from liver tissue. The cyst wall is generally thick, often more than 3mm, with posterior wall echo enhancement. Partial calcification of the cyst wall may result in strong echo, accompanied by acoustic shadowing. The cyst is acoustically transparent, with multiple floating dot-like strong echoes, which may shift with body position, caused by daughter cysts or echinococcus sand. If the mother cyst is filled with larger daughter cysts, it presents as multicystic. The cyst contains strong echo bands that separate into corresponding small cysts, with separation in a petal-like shape. Some cysts may undergo regression, with the cyst fluid being absorbed and its contents transforming into a jelly-like substance. At this time, it presents as a pseudotumor with irregular strong echo plaques and a small amount of liquid dark areas, but the tumor has clear boundaries from liver tissue. When the cyst compresses the bile duct or breaks into the bile duct, intralobular bile duct dilatation can be seen. Cyst compression of the portal vein may cause splenomegaly, and may be accompanied by ascites. Secondary infection of the cyst may present with the sonographic features of liver abscess.

　　Cystic echinococcosis of the liver appears as patchy irregular solid masses similar to liver cancer under B-ultrasound, with unclear boundaries with liver tissue, internal echoes are chaotic, with uneven intensity, and there may be small fluid dark areas in the middle.

　　4. CT examination shows that hydatid cysts in the liver usually appear as low-density lesions of different sizes, solitary or multiple, with smooth edges, round, elliptical, or lobulated shapes on CT images. The CT density value is close to the relative density of water (0~25HU), without enhancement effect. The cyst wall is generally thick, and sometimes there are arched or ring-shaped calcifications. The presence of daughter cysts is one of its characteristics. The relative density of daughter cysts is usually lower than that of the mother cyst. The presence of multiple daughter cysts makes the lesions multicystic. Some people divide the CT images of hydatid cysts in the liver into 3 types: Type A: Small and round daughter cysts distributed in the early stage of the development of the mother cyst; Type B: Large and irregular daughter cysts occupying almost the entire volume of the mother cyst, compressed into petal-like shapes, with thick pseudo-septum between daughter cysts; Type C: Cysts with a longer course, showing higher CT density values of the cyst fluid (40~60HU), with calcification at the edge or inside, a few small daughter cysts located around the mother cyst. When the cyst breaks into the bile duct, it shows signs of bile duct dilation and biliary obstruction. After secondary infection of the cyst, the CT density value of the cyst fluid increases, and gas may appear. The surrounding liver parenchyma shows edema changes.

　　Cystic echinococcosis of the liver manifests as ill-defined low-density patchy lesions. Due to its outward branching characteristics, daughter cysts present as coarse saw-toothed projections at the edge of the lesions. After contrast-enhanced scanning, it is more clear, which is one of its characteristic changes. There are varying sizes of fluid areas within the lesions, making the entire lesion appear like a 'map'. About 80% to 90% of cases show calcification within the lesions, which appears as irregular plaques, fine granules, nodules, or rings.

　　5. Magnetic Resonance Imaging (MRI) examination shows a continuous smooth, uniform thickness, low signal ring-like edge of the hydatid cyst wall on T1-weighted images; it is displayed more clearly on T2-weighted images, which is a characteristic change of the liver hydatid cyst. The contents of the cyst show low signal on T1-weighted images, high signal on T2-weighted images, and low or isosignal on proton density images. If the mother cyst is filled with daughter cysts, the cyst becomes multicystic. After the cyst rupture and infection, the shape of the cyst wall becomes irregular and the internal signal is uneven.

　　6. Radioisotope imaging of hydatid cysts in the liver shows very clear marginal radioactive defects, while cystic echinococcosis of the liver manifests as blurred boundaries and irregular marginal radioactive defects.

　　One, Suitable Foods

　　Red vegetables, especially recommended are carrots, tomatoes, jujube, pitaya, and other red-colored vegetables and fruits.

　　Secondly, Unsuitable foods

　　Canned food, fried and oil-fried foods, instant noodles, sausages, monosodium glutamate, various sweets, sunflower seeds, century eggs, various preserved foods.

　　Thirdly, Food therapy

　　1. Take 4 grams of Jilin Ginseng and 3 grams of American Ginseng with lean meat.

　　2. Boil 4-5 mushrooms with lean meat or chicken breast (drink the soup).

　　3. Take 15 grams of Atractylodes macrocephala, 21 grams of Dangshen, 30 grams of Huai Shan, and 15 grams of lotus seeds with lean meat.

　　4. Take 30 grams of Tufuling, 30 grams of Job's tears, and 3 dates with grass carp or water turtle.

　　5. Take 17 grams of Dangshen, 21 grams of Euryale, 10 grams of Fructus Lycii, and 15 grams of Job's tears with lean meat or chicken breast.

　　6. Take 3 grams of Tianqi and 3 grams of Ginseng (or Red Ginseng) with lean meat or chicken.

　　Firstly, Traditional Chinese medicine treatment methods for echinococcosis of the liver

　　Traditional Chinese medicine therapy is suitable for the condition of worm toxin in the liver.

　　Symptoms: Abdominal pain, fatigue, dizziness, or palpable mass, or ascites, or jaundice, or fever. Tongue is purple with petechiae or ecchymosis, pulse is wiry and thin.

　　Principle: Drain the liver and resolve blood stasis, reinforce the body and expel the worm.

　　Prescription: Modify Biejia Jianwan: 30 grams of Danshen, 13 grams of Huangqi, 45 grams of Dangshen, 45 grams of Danggui, 45 grams of Yujin, 13 grams of Stir-fried Baizhu, 45 grams of Xiangfu, 13 grams of Shanbianlian, 13 grams of Dafupi, 45 grams of Biejia, 16 grams of Shanyao, 13 grams of powder of Xuewan (for冲). For those with jaundice, add Herba Scutellariae, Herba Saururus, Fructus Forsythiae, and Rhizoma Imperata, etc.

　　Secondly, Western medical treatment methods for echinococcosis of the liver

　　1. Drug treatment:

　　(1) Albendazole, praziquantel, and methyldopa all have the effect of killing the protoscolex and destroying the germinative layer of the cysticercus, but they have not yet achieved the goal of cure. Therefore, drug treatment can only be used as an auxiliary treatment, and is only suitable for preventing implantation spread and recurrence, as well as for alveococcosis, before and after surgery. It cannot replace surgery.

　　(2) Different surgical methods are adopted according to whether the cyst has secondary bacterial infection. To prevent the possibility of cyst rupture during surgery, which may cause anaphylactic shock due to the leakage of cyst fluid into the peritoneal cavity, 100mg of hydrocortisone can be administered intravenously before the operation.

　　2. Surgical treatment:It is the most important measure and the most effective method for treating echinococcosis of the liver. The main principle is to remove the inner cyst, prevent the leakage of cyst fluid, eliminate the residual cavity of the outer cyst, and prevent infection. The specific surgical methods can be divided into the following types according to the size of the cyst, whether there is a bile fistula and infection or calcification:

　　(1) Enucleation of the inner cyst

　　The most commonly used and basic surgical method. Suitable for cysts without infection. During the operation, the surrounding area is protected with dressings, and it is completely isolated from abdominal organs and the peritoneal cavity. The cyst is punctured with a long needle equipped with a three-way adapter, and a small amount of cyst fluid is first aspirated, followed by the injection of an equal amount of 4% or 10% formaldehyde solution to kill the scolex. After a few minutes, the cyst fluid is quickly aspirated, and after the inner cyst collapses, it is separated from the outer cyst; the outer cyst is then incised, the inner cyst and the daughter cysts are removed, and the outer cyst wall is wiped with hydrogen peroxide. Efforts are made to close the residual cavity of the outer cyst wall, and in large cases, the omentum can be packed to prevent渗液 infection within the cavity. If such cysts are localized at the edge of the liver, liver resection can also be considered.

　　(2) Inner Cyst Removal and Outer Cyst Closed Drainage Surgery

　　Applicable to large hydatid cysts with infection or bile fistula, which are difficult to collapse due to the wall, and closed drainage is placed after the inner cyst removal.

　　(3) Inner Cyst Removal and Outer Cyst One Jejunum 'Y' Type Internal Drainage Surgery

　　Used for the outer cyst cavity of large hydatid cysts that are difficult to collapse and close due to adhesion to larger bile ducts. The anastomosis should be wide, and side吻合with the jejunum is preferred.

　　(4) Saccular Suture Technique

　　It was once used for cases with concurrent infection, but all formed mixed infections and bile fistulas, becoming long-lasting complex fistulas, causing great suffering to patients. Now it is gradually abandoned and replaced with thorough cleaning of the cavity, trying to minimize the residual cavity after leaving a closed drainage tube, and配合antibacterial treatment to close the residual cavity as soon as possible.

　　(5) Liver Resection

　　Used for cases of calcified liver hydatid and vesicular echinococcosis. For vesicular echinococcosis, a more proactive attitude is held towards liver resection, as long as the lesions are relatively localized, efforts should be made to resect them, including segments, lobes, half liver, or irregular resection. However, if the lesions are widely distributed or have invaded the porta hepatis, they should be considered as contraindications for liver resection.

　　(6) Treatment for hydatid cysts with bile fistula

　　It can be treated by suture of the fistula in the cyst cavity under direct vision with fine needle and thread, and filling with omentum, which is very effective. In recent years, applying TH glue to the sutured fistula has also played a reinforcing role. The key to treating bile fistula is to repeatedly wipe the cyst cavity with white gauze, check for bile staining, to avoid ignoring the fistula, repair failure, and leaving other bile fistulas.

　　(7) Treatment for hydatid cysts rupturing into the abdominal cavity

　　It is necessary to perform laparotomy as soon as possible while actively treating anaphylactic shock. The key to the operation is to repeatedly flush the abdominal cavity with 10% hypertonic saline, strive to completely remove the scolex and daughter cysts, and treat the hydatid cysts. To prevent the formation of secondary abdominal hydatid cysts, antihydatid drugs must be taken for at least 3 months after surgery.

　　(8) Treatment for hydatid cysts rupturing into the bile duct

　　For those with hydatid cysts that rupture into the bile duct, it is necessary to promptly explore the bile duct, remove the fragments and daughter cysts of the inner cyst, repeatedly flush with hypertonic saline after placement of a T-shaped tube for drainage, and treat the remaining hydatid cavity and repair the bile fistula.

　　(9) The removal of the inner cyst of the hydatid cyst using laparoscopic surgery is completely feasible. In addition, for patients with advanced liver echinococcosis, liver transplantation can be adopted.