congenital bronchopulmonary cyst
Introduction
Introduction to congenital bronchopulmonary cyst Congenital bronchopulmonary cyst refers to a congenital cyst containing a bronchial tissue component and containing mucus or gas. It has been called congenital cystic bronchiectasis or congenital bronchogenic cyst. It is currently considered that congenital bronchopulmonary cyst is In the most active phase of tracheal development 26 to 40 days of lung embryo development, small lung parenchymal cells in the distal part of the lung bud are separated from it during the branching process, and ectopic development, but unlike lung isolation, it does not Further development, it can be considered that bronchial cysts, pulmonary isolation (including intra- and extra-leaf), and congenital cystic bronchiectasis are within a category of similar etiology and pathology. Similar to lung isolation, the time of occurrence of an abnormal germ determines its location. Abnormal development occurs earlier, when the lung germ is still developing near the atmospheric tube, the cyst is located in the mediastinum or hilar, called bronchogenic cyst; while the abnormal development appears later, the abnormal germ is easy to stay in the lung, and the cyst is mostly located in the lung. It is called a lung cyst. basic knowledge The proportion of sickness: 0.0004% - 0.0007% Susceptible people: young children Mode of infection: non-infectious Complications: pneumothorax
Cause
Causes of congenital bronchopulmonary cyst
(1) Causes of the disease
During the embryonic development, the lung buds from the gut are gradually developed to form bronchial trees and alveoli. The lung buds are cord-like structures in the early stage of development, and gradually evolve into a tubular shape. If the embryo development is impaired, the cable-like structure cannot evolve into a tubular shape. The distal bronchial tissue is separated from the proximal tissue, and a blind tube is gradually formed. The secretion in the lumen cannot be discharged, and the accumulation and expansion form a mucus-containing cyst.
(two) pathogenesis
Due to the different time and location of lung bud development disorders, cysts vary in size, can be single or multiple, rare bilateral onset, if the lung bud strips are not developed before the development of the barrier to form a single, isolated Pulmonary cyst, if the lung bud development disorder occurs after branching, it forms multiple pulmonary cysts. If the 1-leaf or multi-leaf lung tissue is occupied by the honeycomb lung cyst, it is called polycystic lung, and the lung is 50%~ 70%, more common in the left lung, cysts formed in the developmental disorders of the trachea or main bronchial branches, most of which are located in the mediastinum, called bronchogenic cysts, often located near the tracheal bifurcation or the main bronchus, and the cysts are rarely directly related to the trachea. In common, most of them are close to the trachea or a cartilage fistula between them, and cysts formed in the developmental disorders of the small bronchiole branch, mostly located in the lung tissue, called pulmonary cysts.
Congenital pulmonary cysts have different thicknesses, ranging from 2 to 10 cm in diameter. The inner layer is composed of columnar or pseudostratified ciliated epithelial cells. If infection occurs, it can be covered by squamous epithelium, partly inflamed granulation tissue; outer layer There are elastic fibers, smooth muscle fibers, mucous glands, cartilage tissue and connective tissue. Some lung cysts can not find mucous glands and cartilage, but there are clear columnar and pseudo-stratified ciliated epithelial cells and other tissue structures. This is because cysts occur in alveoli. Because of the peripheral bronchus, it should still be diagnosed as a congenital bronchopulmonary cyst. Because there is no respiratory ventilation in the cyst, there is no charcoal pigmentation in the cystic wall. This is a characteristic of congenital cyst, easy to distinguish from acquired cyst, congenital lung. After infection of the cyst, the destruction of the epithelial layer is easily confused with the acquired pulmonary cyst. The wall of the bronchial cyst is also composed of pseudostratified ciliated epithelium, cartilage, smooth muscle, fibrous tissue and mucous gland. Individual bronchogenic cysts can be malignant. Or bronchial adenoma, some cysts, especially those closely associated with the esophagus, containing ciliated epithelium, squamous epithelium or Mucosa, sometimes with the four kinds of epithelial cysts in one.
The inner wall of the cyst may be smooth or have a trabecular trabeculae. The cyst is filled with mucus, which is called a fluid cyst. The liquid in the fluid cyst may be a clear liquid or a blood or a solidified blood clot. If the cyst and the bronchus are connected, the passage is fine. Part of the mucus is discharged, and at the same time, the gas enters the capsule, which can become a balloon swelling or a liquid balloon swelling. If the channel is unblocked, the mucus in the cyst is completely discharged, and the capsule is completely filled with gas, which is called a balloon swelling. If the channel is infected due to infection, it will live. The flap forms a tension cyst, which is one of the common complications, often compressing normal lung tissue, causing more serious clinical symptoms.
Prevention
Congenital bronchopulmonary cyst prevention
Usually pay attention to prevent colds.
Complication
Congenital bronchopulmonary cyst complications Complications
Can be complicated by pneumothorax.
Symptom
Symptoms of congenital bronchopulmonary cysts Common symptoms Dry cough, sputum, purulent abscess, secondary infection, shortness of breath, tracheal pressure, dyspnea, breath sounds, weakened dysphagia
The symptoms of congenital bronchopulmonary cysts and the appearance of early and late, due to their location, size and presence or absence of comorbidities, adult bronchopulmonary cysts are often asymptomatic, most cases were found by X-ray examination or autopsy, in the mediastinum Simple bronchogenic cysts are mainly caused by compression symptoms. Bronchial compression may have dry cough, wheezing and varying degrees of difficulty in breathing. Compression of the esophagus may cause difficulty in swallowing and feeding. Blocking the airway may form a tension cyst to compress the trachea and heart. Cause displacement, obvious air urgency, difficulty breathing, cyanosis, if not treated in time, can be life-threatening, congenital pulmonary cyst and bronchial traffic, often secondary infection, cough, cough or hemoptysis, fever, or cough a lot of pus, similar to lung abscess, bronchiectasis, a small number of patients may have massive hemorrhage in the cyst, rupture to the chest, resulting in spontaneous pneumothorax or blood pneumothorax, the signs vary depending on the size of the cyst, the larger cyst is filled with fluid, the percussion is partial Sound; large gas cysts may have local drum sounds, respiratory sounds weakened or disappeared during auscultation, small cysts located in lung parenchyma No secondary infection, can be used without any signs and symptoms.
Examine
Examination of congenital bronchopulmonary cyst
Cysts combined with infection of white blood cells can be elevated.
1. X-ray examination: the isolated lower lobe of the lung cyst is more common than the upper lobe. The fluid cyst is round or elliptical. The density is uniform and the edge is sharp. The balloon is swollen with a thin-walled ring-shaped translucent shadow. The larger the cyst. The thinner the wall, the larger the volume of the tensioning pulmonary cyst can be, compressing the normal lung tissue, so that the lung texture is only in the apex of the lung or the rib angle, and even the mediastinum is pushed to the healthy side. The huge cystic swelling can even pass over the anterior mediastinum. Into the contralateral chest. Multiple pulmonary cysts, also known as polycystic lungs, are generally cystic, with diffuse thin-walled translucent shadows on one or both sides of the lungs, which may contain small fluid levels and multiple infections. Liquid level, due to the relationship of the title, is generally more common in the lower lung field than in the upper lung field, the size of the airbag shadows can be overlapped, densely shaped like a honeycomb. Pulmonary cysts with concurrent infection can be seen on the X-ray. Invasive inflammation shadows around the cysts, thickening of the cyst wall, adhesion of the cysts to the surrounding tissues after inflammation absorption, irregular X-ray morphology, pleural thickening adhesions, loss of typical circular or Oval shadow, bronchial cysts appear circular or elliptical on X-ray chest, with clear outline, smooth edges, uniform density, no lobulated shape, no calcified shadows, attached to the trachea, one side of the main bronchial wall, It can be slightly flat due to the trachea and the main bronchial wall. It has a certain diagnostic significance. The cyst attached to the tracheal wall can move up and down with the swallowing action.
2. Bronchography: It helps to determine the lung segment where the lung cyst is located. The infection affects the pleura. The pulmonary cyst caused by bronchial dysplasia shows a decrease in bronchial branching during angiography. The contrast agent generally does not enter the cyst, only the balloon that communicates with the bronchus Only the contrast agent enters, this kind of lung cyst is easy to be secondary infection, so it is not suitable for bronchography. If it is necessary, it is better not to use iodized oil during angiography, and to use the easily absorbed diatrizoate to prevent infection.
3. CT scan: can further understand the size and extent of the cyst, and also help to understand the density of the cyst and the thickness of the cyst wall, whether the edge is smooth, easy to identify with the tumor, but also the cyst wall caused by the malignant cyst Regular shadows should be avoided. A needle biopsy should be avoided to prevent cysts from rupturing and infecting.
Diagnosis
Diagnosis and diagnosis of congenital bronchopulmonary cyst
Combined with clinical manifestations and X-ray examination, the diagnosis of bronchopulmonary cysts can be confirmed.
Differential diagnosis
Bronchopulmonary cysts need to be identified with the following diseases:
Acquired pulmonary air sac
In bacterial pneumonia, the scaffold structure of the lung tissue is broken, the obstruction at the end of the bronchus occurs, and the valve is caused to cause pulmonary air sac. The congenital and acquired pulmonary cysts (the emphysema bullae and emphysema after inflammation) are thin. The hollow cystic cavity is difficult to identify from the X-ray, but emphysema pulmonary bullae is often accompanied by emphysema of the surrounding lung tissue, and infectious emphysema often has a clear history of pulmonary infection, and the disease develops rapidly. There are many changes in clinical manifestations. The sacral edge of the bullae of the lung bullae is blurred, mostly located inside the lung, and can be cured and absorbed.
2. Lung abscess cavity
Congenital pulmonary cysts with infection, clinical high fever, cough and sputum and even hemoptysis, are very similar to lung abscess, X-ray lesions have liquid level, surrounded by inflammatory infiltration, also similar to lung abscess, the difference is the lung The wall of the abscess is thicker, the surrounding inflammatory infiltration is heavier, the fluid in the cavity is generally more, the shape is irregular, and it occurs in the posterior and lower leaves of the upper lobe. After the inflammation subsides, no trace can be left, and the cyst infection is cured. The circle-shaped shadow of the posterior cyst still exists, and bronchial dilatation and buckling stenosis can be seen by bronchography.
3. Tuberculosis purification cavity
Tuberculosis purification cavity can also be a thin-walled cavity, shaped like a cyst, the inner wall can also cover the epithelial tissue, but the wall does not contain cartilage, gland and smooth muscle tissue, common carbon terminal deposition and often occurs in the upper lobe, often with tuberculous infiltration around Shadow, adjacent to the satellite stove, clinically can have low fever, fatigue, weight loss and other symptoms of tuberculosis.
4. Congenital paralysis
Congenital pulmonary cysts in the X-ray chest radiographs of multiple ring-shaped translucent images, especially in the left lower lobe and congenital diaphragmatic ring shape is similar, clinically there are no cases of false open laparotomy, the identification point is congenital diaphragmatic circle The shape of the translucent image is continuous, the image changes with the peristalsis of the intestines, the bowel sounds are often heard in the physical examination, and sometimes accompanied by abdominal symptoms such as abdominal pain; the shape of the congenital pulmonary cyst is separated by the diaphragm, not with the shadow of the abdominal cavity. Continuous, the shape is basically fixed and unchanged, and the wet snoring is occasionally heard in the clinic.
5. Lung isolation
The posterior pelvic segment of the lower lobe is multiple, which is a single or multiple circular or elliptical cyst shadow. When it is connected with the bronchus, the liquid level is visible. The chest radiograph is basically consistent with the pulmonary cyst. The preoperative identification is difficult, but the isolated pulmonary artery is from the descendant. The arteries can only be diagnosed if they have a descending aorta angiography, an arterial branch is seen in the cyst, or an arterial vessel from the systemic circulation is found during surgery.
6. Mediastinal tumor
Bronchial cysts often occur in the paratracheal, subcarinal and hilar, and should be confused with mediastinal tumors and enlarged lymph nodes. The boundaries of bronchial cysts are clear, smooth, burr-free, uniform in density, and rarely have lobular changes. The main points of diagnosis.
7. Esophageal cyst esophageal cyst and bronchogenic cyst
All of them are caused by abnormal development of the foregut, so they are often referred to as foregut cysts. The esophageal cysts are located near the posterior mediastinal esophagus. The inner wall of the cavity is covered with squamous epithelium. The wall contains skeletal muscle and contains no cartilage. In addition, the tension contains balloon swelling. Must also be identified with pneumothorax.
