Pulmonary schistosomiasis

Introduction to pulmonary schistosomiasis Pulmonary schistosomiasis (pulmonaryschistosomiasis) is a larvae of schistosomiasis. Adults migrate, develop, and parasitize in the lungs, or their eggs are deposited in the lung tissue, causing inflammation, abscess, granuloma, and pseudotuberculosis in the lungs. The manifested lesions are also the most common ectopic schistosomiasis. In addition to the general symptoms of schistosomiasis, they often present with respiratory symptoms such as fever, cough, cough, hemoptysis, chest pain or asthma. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: fecal-mouth transmission Complications: heart failure

Causes of pulmonary schistosomiasis

Causes:

The feces, urine, sputum and other excretions of schistosomiasis contain live eggs, especially live eggs in feces, which are the main source of infection. These excrements containing live eggs can contaminate water sources, ponds, hatch into burrs in water, and ticks infected. After the snail is formed, the snail is formed, and the medium is mainly snail. The scorpion in the snail can escape for at least one and a half years. The transmission route is mainly through contact with the infected water, such as swimming, laundry, fishing, etc. When water is invaded from the oral mucosa, any gender, age, and occupational population are susceptible populations. Due to repeated infections in epidemic areas, the degree of infection increases with age.

Pathogenesis:

In the epidemic water, the cercaria invades the skin when it comes into contact with the human body, and turns off the tail to become a child worm. The child worm stays under the skin for 5-6 hours, that is, enters the small blood vessels and lymphatic vessels, and generally flows with the blood on the second day after the invasion. The heart and pulmonary artery reach the capillaries of the lungs. On the 8th to 9th day after the invasion, the larvae reach the portal system and develop into adult worms. After that, the adults are retrogradely parasitized to the superior iliac vein and the inferior mesenteric vein, and lay eggs, from infection to production. The eggs are generally 4 to 6 weeks. The schistosomiasis is mainly parasitic in the blood vessels of the human portal system. The eggs produced by the adults are mainly deposited in the intestinal mucosa and in the liver tissue. If the adult parasites and eggs are outside the range, When the organ tissues cause damage, it is called ectopic schistosomiasis. The schistosomiasis eggs can be circulated into the lungs through the collateral veins of the hepatic vein or portal vein, deposited in the lung tissue, and occasionally the schistosomiasis parasitizes in the lungs, even females. Male worms and eggs are spawned. The worms that reach the lungs can pass through the alveolar wall capillaries and enter the thoracic cavity. The mediastinum, transverse to the abdominal cavity, enters the portal system, and after the acute phase or due to the small amount of cercariae in the lungs Long-term infection and invasion, the formation of chronic pulmonary schistosomiasis.

The migration of the worm to the lungs can cause pathological changes in allergic pneumonia such as hyperemia, hemorrhage and eosinophil infiltration. These lesions often appear 1 to 2 weeks after infection and disappear quickly. The eggs are deposited in the lungs. The response varies with the degree of maturity: mature eggs can cause tissue necrosis and acute exudative inflammation, endometritis often occurs in the egg deposits, eosinophilic granuloma, acute abscess can form when infected, with The death of the egg, the abscess is gradually absorbed to form a granuloma, the granuloma contains a large number of epithelial cells and foreign body giant cells, similar to the tuberculous nodules, known as "pseudotuberculosis", small granulomas can gradually Fibrosis, even after the death of the eggs, calcification; the immature eggs cause less tissue reaction, although there are also "pseudotuberculosis" formation, but eosinophils and neutrophils infiltration, chronic schistosomiasis Mainly due to mechanical or chemical stimulation of schistosomiasis eggs deposited in the lungs, causing pulmonary interstitial, bronchial submucosal congestion, edema, ulcer formation, bronchi, bronchioleal stenosis, adhesion Membrane epithelium and fibrous tissue hyperplasia, cell infiltration, etc. change.

Pulmonary schistosomiasis prevention

Actively treat patients, sick animals, to control the source of infection, manage feces, reduce water pollution, eliminate snails to eliminate intermediate hosts, pay attention to personal protection, and avoid contact with infected water.

Pulmonary schistosomiasis complications Complications heart failure

Can lead to pulmonary heart disease, heart failure.

Symptoms of pulmonary schistosomiasis Common symptoms Fecal or rectal sigmoid... Intermittent heat relaxation, hot lymph nodes, swollen abdominal pain, low heat, acute dyspnea, vocal nausea

The onset season is mostly in summer and autumn, depending on the amount of invading pathogens and the extent of lung lesions. After 1 to 2 weeks after acute infection, the mechanical damage caused by the transfer of the larvae in vivo and the human body metabolites The reaction has different degrees of symptoms, such as relaxation or low fever (a few have high fever), cough, cough, blood in the sputum, chest pain or asthma, but also abdominal pain, itching, urticaria and other allergic symptoms in the body Adults have a large number of spawning periods, which is equivalent to a minimum of 10 days after the first infection, and the longest is 2 months. Most of the acute onsets vary in severity. The clinical manifestations are mainly fever, with intermittent heat and relaxation heat. More common, morning and evening fluctuations, the patient may have dry cough, shortness of breath, chest pain, palpitations, lung auscultation can be heard and dry, wet voice, severe can cause diffuse, occlusive pulmonary arteritis, a few can cause Pulmonary hypertension and heart failure, this period can also cause severe allergic reactions, urticaria, bronchial asthma, angioedema, lymphadenopathy, etc., acute abscess formation around the egg, can have shortness of breath Asthma, chest pain, hemoptysis or pus and blood stasis, accompanied by nausea, vomiting, abdominal pain, diarrhea and other abdominal symptoms are quite common in the early stage, may be part of the allergic reaction, but persistent diarrhea is caused by the stimulation of the egg to the intestinal mucosa, lung The chronic phase of schistosomiasis can be manifested as schistosomiasis chronic bronchitis, recurrent allergic pneumonia, bronchiectasis, pleurisy and so on.

Examination of pulmonary schistosomiasis

In the acute phase, the total number of white blood cells and eosinophil counts are increased. Eosinophils generally account for 15% to 20%, and even 70%. The increase in eosinophils is not proportional to the severity of infection. In severe cases, the number of patients may not increase, or See reduction, or substitution of neutrophils, is a dangerous sign, eosinophils in patients with chronic schistosomiasis generally do not exceed 20%, while late cases are not obvious increase, may also be associated with decreased hemoglobin, liver function Abnormal, the positive rate of direct smear is not high, so the precipitation and hatching methods are generally used. The sputum can also find the eggs or edulis by direct smear or precipitation and hatching. Rectal mucosa biopsy or tableting can find the worm. Eggs, immunological tests such as schistosomiasis antigen intradermal test, ring egg sedimentation test, cerebral palpebral membrane test and immunoelectrophoresis detection of antigen can provide auxiliary diagnosis.

1. X-ray examination mostly has a clear lung substantial change, showing increased lung texture, flaky shadows, miliary changes, enlarged hilar shadows, etc., early two lungs texture enhanced, followed by scattered punctiform infiltration of both lungs, The edge is blurred, and the middle and lower lung fields are more. As the disease progresses, the lung shadows tend to be dense and have a tendency to fuse with each other. It resembles bronchial pneumonia. When the eggs die, the surrounding tissue disappears and the lesions gradually shrink and shrink. Turned to clear and tidy, leaving a dotted shadow, similar to the performance of miliary tuberculosis, after the point shadow gradually reduced, sometimes visible calcification, typical X-ray lesions generally disappear within 3 to 6 months, a small number of cases of pulmonary arterioles Extensive occlusion can cause pulmonary hypertension and right heart hypertrophy. If there are repeated episodes of contact with water, repeated infections, lung fields may have new and old, miliary shadows of varying density and uneven size, chronic pulmonary schistosomiasis can be manifested There is a slab-like shadow with increased density, which has a clear boundary with healthy lung tissue, such as an inflammatory pseudotumor or tumor.

2. In the acute phase of bronchoscopy pulmonary schistosomiasis, bronchial mucosal congestion, edema and submucosal yellow granules were observed in some cases under fiberoptic bronchoscopy; superficial ulcers, miliary nodules, scars, bronchial lumen stenosis were observed in the chronic phase. Secretion of secretions, etc., can be found by bronchial brush examination, bronchial mucosal biopsy to find schistosomiasis eggs, the most common eggs are calcified shells or empty shells (black), occasionally mature or immature live eggs, live eggs are colorless and transparent, The edulis are clearly visible. For example, the morphological changes of the eggs may be dead eggs, and the dead eggs of schistosomiasis may remain in the tissue for a long time and do not disappear.

Diagnosis and identification of pulmonary schistosomiasis

It is mainly based on the history of schistosomiasis endemic areas and contact with infected water, and has other symptoms of general schistosomiasis. X-ray films suggest small or miliary lesions or inflammatory lesions in the lungs, with varying degrees of cough and chest pain. , hemoptysis, asthma, dyspnea and other symptoms, sputum eggs found in sputum, or bronchial brush examination, bronchial mucosa biopsy to find schistosomiasis eggs; fecal or rectal, sigmoid mucosal biopsy to find schistosomiasis eggs, blood eosinophils increased, immunology Tests such as positive skin tests, positive ring test, etc., can help diagnose.

Pulmonary schistosomiasis should be differentiated from miliary tuberculosis, silicosis, chronic bronchitis, bronchial asthma and non-specific lobular pneumonia.

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