Overview
Echinococcosis is a chronic parasitic disease caused by the parasitization of the human body by the larvae of the echinococcal tapeworm Echinococcus vesiculosus (Echinococcus vesiculosus), also known as Echinococcus vesiculosus (Ae) and multihomed encapsulated disease. The course of the disease is long, with the characteristics of invasive progressive. From the biology, epidemiology, pathology and clinical manifestations, vesicular and cystic schistosomiasis are significantly different.
Etiology
Echinococcus multilocularis is slightly smaller than Echinococcus granulosus. Adult tapeworms are 1.3-3.0 mm long and 0.28-0.51 mm wide, with four or five segments. The head segment has four suckers. There are two rings of small hooks on the parietal process, totaling 13 to 34, varying in size. The ovary is divided into 2 lobes, located in the middle of the posterior half of the segment. The uterus is curved and expanded into a pouch at the end, or spherical, with no lateral branches, unlike the uterus with 12-15 branches in the fine-grained echinococcus tapeworm gestation segment, the pregnant segment uterus has no lateral capsule, and contains the eggs of the worm, which are 300 on the average. The number of testes in mature segments ranged from 26 to 36, which was less than that of fine-grained echinococcus tapeworms (45-65). The genital pores are all on the lateral margins in front of the mid-transverse line, and are mostly irregularly staggered openings; lateral openings are also seen.
Symptoms
The incubation period is long, usually 20 years or more from infection to onset of disease. Multi-compartmental echinococcosis has a long course and is characterized by insidious progressiveness. There are no clinical symptoms in the early stage, and they are only detected during B-mode ultrasound examination of the liver.
1. Hepatic multilocular echinococcosis
The main symptom of the patient at the time of consultation is vague pain or (with) mass in the epigastrium. It can be categorized according to clinical manifestations:
(1) Simple hepatomegaly type Clinical symptoms vary depending on the location and size of the lesion. The top of the right lobe of the liver is the most common site, and the liver is enlarged behind the back and upward medially, elevating the diaphragm, and sometimes the liver is not detected under the ribs. Abdominal pain may radiate to the back of the right shoulder. If the lesion is located in the left lobe of the liver, the epigastric mass appears in the early stage of the disease, which is easy to detect. The general condition of the patients varies depending on the duration of the disease and the size of the intrahepatic lesion. In mild cases, the general condition is still good, in severe cases, the whole lobe or both lobes of the liver have extensive lesions, and the patients have systemic symptoms such as fatigue and emaciation.
(2) Obstructive jaundice type The lesions of vesicular larvae involve the hepatic hilum, compressing the common bile duct and causing obstructive jaundice. Jaundice is progressive and often accompanied by gastrointestinal symptoms such as skin itching and loss of appetite.
(3) Giant liver nodule type or known as hepatocellular carcinoma type is mainly manifested as an epigastric mass with localized elevation. The left and right lobes of the liver are extremely enlarged, about 10 cm below the margin and the fenestra, hard, and multiple nodules of different sizes can be found on the surface. Ultrasound and CT scan of the liver showed that the whole lobe of the liver was largely destroyed, while the other lobe showed significant compensatory enlargement, and the latter was softer in texture.
2. Pulmonary multilocular echinococcosis
Lung lesions can be caused by the right lobe of the liver invading the diaphragm and then reaching the lungs, or due to hematogenous metastasis. Clinical symptoms are mainly small hemoptysis. A small amount of pleural effusion may occur in a few patients.
3. Cerebral multilocular echinococcosis
The main clinical symptoms are epileptic seizures and increased intracranial pressure, such as limited epilepsy or hemiparesis, but it depends on the location of the lesion. Cranial CT scans show foveal hypodense lesions in the temporal or (and) occipital lobes. All patients with the cerebral form have significant hepatic and pulmonary multilocular echinococcosis.
4. Other
After human infection with Baobab, sensitization is often caused by the absorption of a small amount of antigen, and in severe cases, death can be caused by anaphylactic shock.
Examination
1.Laboratory examination
Blood eosinophils are mildly increased. Liver function tests are mostly normal, and only a few advanced patients have increased serum alanine aminotransferase and alkaline phosphatase, decreased albumin, increased globulin, and the ratio of albumin/globulin is ≤1 due to extensive liver lesions.
2. Serologic examination
Immunologic examination for specific antibodies. Most intradermal tests for encapsulated worms are positive. In a few negative skin tests, ELISA for serum parasites is mostly positive.
3. Imaging examination
Liver ultrasound, hepatic nuclide scan, liver CT, chest X-ray, cranial CT/magnetic resonance imaging (MRI) are helpful for diagnosis.
(1) Ultrasound of the liver
Ultrasound examination of the liver can show an inhomogeneous mass in the liver with disturbed internal structure and irregular edges. The center of the mass is necrotic liquefaction dark area, and there are speckled strong echogenic calcification foci.
(2) CT scan of the liver
There is an irregular and inhomogeneous hypodense area with no obvious boundary, in the center of which there are necrotic cavities and foci of stippled calcification. The large necrotic cavities have uneven walls, which are different from the cysts and are called pseudocystic cysticercosis.
Diagnosis
1. Epidemiologic history
The patient comes from an endemic area, or has lived in the infected area for a long time, and has a history of close contact with dogs, foxes, etc., or hunters who hunt and kill foxes and skin them.
2. Clinical symptoms
Liver enlargement and vague pain: abdominal mass, hard, surface nodules, ill-defined substantial lesions by ultrasound or CT examination, which is an important reference value for diagnosis.
3. Immunological test
Most of the intradermal test for encapsulated worms is positive, and it is often a strong positive reaction; occasionally there are negative skin test, serum enzyme-linked immunosorbent assay (ELISA) and Em2 antigen and Eml8 antigen detection of blood antibody test, its specificity and sensitivity are high, and there is little cross-reactivity, which can be used to identify vesicular and cystic encapsulated worm disease.
Treatment
1. Surgical treatment
The treatment mainly relies on surgery, so we should strive for early diagnosis, and should strive to be carried out before the occurrence of compression symptoms or complications. Many patients do not consult the doctor until they have obvious symptoms such as cirrhosis, jaundice and portal hypertension, and they often miss the time of surgical treatment.
Before surgery, the cystic fluid should be removed with a fine needle to prevent spillage of the cystic fluid, and then the internal capsule should be removed. The internal capsule and the external capsule are only mildly adherent, very easy to peel off, and can often be removed completely. Before surgical removal of the internal capsule, 2% formaldehyde (formalin), 0.01% hydrogen peroxide, 1% iodine, 0.05% hypochlorite or 25% glycerol can be injected into the capsule to kill protozoa, and the latter four are more effective than formaldehyde, and the toxicity of hydrogen peroxide and glycerol is also lower.
2.Drug treatment
(1) Mebendazole (mebendazole) oral, a total of 16 to 48 weeks of treatment of worm disease, patients can tolerate; but some people in the application of drugs 3 months later, take the cystic fluid for animal inoculation, but still get a positive result, it is thought that the oral blood concentration of this product is low, the efficacy is still difficult to determine, and is currently only used as a complementary treatment of surgical therapy.
(2) Albendazole (propylthiomidazole) has high concentration in tissues and cysts of worms. It is taken orally, 30 days as a course of treatment, and its efficacy is still satisfactory.