atelectasis in children
Introduction
Introduction to pediatric atelectasis Atelectasis should indicate that the lungs have never been filled with gas after birth, and that the already inflated lung tissue loses its original gas (ea) and should be called pulmonary collapse. However, due to years of habits, generalized atelectasis can include congenital atelectasis and acquired lung collapse, and the term insufficiency is still used here. Atelectasis is manifested as non-inflated in the alveoli, causing alveolar collapse. basic knowledge Sickness ratio: 0.0001% Susceptible people: children Mode of infection: non-infectious Complications: emphysema, bronchiectasis
Cause
Pediatric atelectasis
(1) Causes of the disease
Atelectasis is more common in childhood, and lung tissue can be collapsed or airless for a variety of reasons, resulting in loss of normal function, or can be divided into three categories according to its etiology:
1. External force oppression: The lung parenchyma or bronchus is oppressed, and there are the following four situations:
(1) Thoracic dyskinesia: abnormalities in nerves, muscles and bones, such as cerebral palsy, poliomyelitis, polyneuritis, spinal muscular atrophy, myasthenia gravis and skeletal malformations (vitamin D deficiency, funnel chest, spine Scoliosis, etc., Beijing is most common with multiple radiculitis.
(2) diaphragmatic dyskinesia: due to paralysis of the phrenic nerve or increased intra-abdominal pressure, often caused by a large number of ascites caused by various reasons.
(3) lung expansion is limited: due to negative pressure or increased pressure in the thoracic cavity, such as pleural effusion, gas accumulation, empyema, hemothorax, chylothorax, tension pneumothorax, sputum, tumor and heart enlargement.
(4) bronchial compression by external force: due to enlarged lymph nodes, tumor, vascular ring or cyst compression, bronchial lumen blockage, air can not enter the lung tissue, enlarged left atrium and pulmonary artery can oppress left common bronchus leading to left atelectasis The common cases in Beijing Children's Hospital belong to the atelectasis caused by tumor-type bronchial lymph node tuberculosis. Two children with high ventricular septal defect have also seen the left ventricular blood directly into the pulmonary artery through the defect, resulting in enlargement of the pulmonary artery and compression of the left common bronchus. Causes total left atelectasis.
2. Obstruction in the bronchi or bronchiole: The bronchial lumen is blocked, and there are several cases:
(1) foreign body: foreign body block bronchus or bronchioles cause lobary or segmental atelectasis, occasional foreign body block the trachea or main bronchus caused by bilateral or one side of atelectasis.
(2) bronchial lesions: tracheobronchial softening, airway stenosis, bronchial submucosal tuberculosis, tuberculous granulation tissue, diphtheria pseudomembrane extension and trachea and bronchi, bronchiectasis.
(3) bronchial wall sputum and viscous secretions in the lumen: the baby's respiratory tract is narrow, easy to be blocked, suffering from pulmonary inflammatory diseases such as pneumonia, bronchitis, whooping cough, measles, cystic fibrosis, ciliary movement Obstruction, immunodeficiency, chronic lung disease in neonates, postoperative esophageal atresia, and bronchial asthma, bronchial mucosal swelling, smooth muscle spasm, thick secretions can block the airway and cause atelectasis. Such causes are more common in winter and spring. Therefore, the onset of atelectasis is also more in the cold season, cough medicines such as opioids, atropine can reduce the natural cough, and can make the secretions thicker, can increase the obstruction, it can not be abused, polio or other causes When the diaphragm and chest muscles are low or even paralyzed, the bronchial secretions are not easy to cough up. In the case of chest surgery, long-term general anesthesia, deep anesthesia or traumatic shock, bronchospasm caused by stimulation, bronchial secretions Originally increased, such as cough reflexes are inhibited or disappeared, secretions are more likely to block the lumen, causing lungs Zhang, bronchiolitis, interstitial pneumonia and bronchial asthma often cause obstruction of most bronchioles, the initial manifestation of obstructive emphysema, followed by partial obstruction, the formation of atelectasis, and emphysema According to the results of bronchoscopy, the formation of obstructive atelectasis can be elucidated.
3. Non-obstructive atelectasis:
In addition to the above two categories, in recent years, more attention has been paid to non-obstructive atelectasis. The main reasons are:
(1) lack of surfactant (active surfactant): pulmonary surfactant is produced by type II alveolar epithelial cells, is a phospholipid protein complex, plays a major role in dipalmitoyl lecithin, and the surface active substance is coated on the inner surface of the alveoli. It has the function of reducing the surface tension of the air-liquid interface of the alveoli, and has the function of stabilizing the alveolar to prevent alveolar collapse. If the surface active substance is lacking, the surface tension of the alveoli is increased, the alveolar retractive force is increased, and the alveoli is collapsed, resulting in a lot of At the microinelectasis, pulmonary surfactant deficiency can be seen in: 1 premature infants with immature lung development, 2 bronchial pneumonia, especially viral pneumonia, reduced surface active substance production, 3 trauma, shock and other initial hyperventilation , rapid consumption of surfactants, 4 inhalation of toxic gas or pulmonary edema, etc., causing surfactant damage and denaturation, the surface tension of normal lung is 6dyn / cm 2 , and the surface tension of infants with respiratory distress can reach up to the lack of surfactant 23dyn/cm 2 .
(2) Another type of non-obstructive atelectasis may be related to the neuromuscular structure of the terminal airway of the lung: Many scholars have confirmed that there is a muscle elastic fiber in the alveolar duct and alveolar sac, which is interwoven with smooth muscle and elastic fibers. Together, controlled by autonomic nerves, when severe pain such as rib fractures and surgery, or when the bronchus is strongly stimulated, such as bronchography, contraction of muscle elastic fibers can cause atelectasis, especially large lung collapse.
(3) too shallow breathing: such as after surgery and application of morphine, or coma and extremely debilitated patients can see superficial breathing, when the pressure in the lungs is reduced enough to resist local surface tension, it can gradually cause alveolar closure and lung Zhang, encourage deep breathing after surgery to prevent alveolar closure, or reopen the alveoli that is closed due to shallow breathing. In short, atelectasis is more common in children, the cause of which is bronchiolitis, bronchitis, asthma, bronchus Lymph node tuberculosis, multiple radiculitis, bronchial foreign body and more common after surgery, in addition, can also be seen in aspiration pneumonia, bronchiectasis, intracranial hemorrhage, endocardial fibroelastosis, congenital heart disease, tumors and so on.
(two) pathogenesis
Bronchial obstruction
First, it causes obstructive emphysema, and the air in the alveoli accumulates and is gradually absorbed by the blood, resulting in alveolar collapse. The extent of collapse is affected by the development of the Kohn hole between the alveoli and the Lambert tubule of the bronchiole-alveolar channel. The younger the child, the more common the lung atelectasis, the larger the range, the less the influence of blood perfusion in the alveolar collapse area, so the ventilation/perfusion rate changes, the right to left shunt occurs, and the low O2 blood with different severity Symptoms, when the obstruction occurs, there is accumulation and stagnation of secretion in the tracheal cavity, which promotes bacterial reproduction, accumulation of alveolar endocrine fluid, and the volume of the collapsed lung segment sometimes increases more than normal. This condition is called flooding lung, and the endocrine fluid is absorbed for 36 hours. The segment is narrowed, and the inflated alveolar hyperinflation or emphysema is present around the atelectasis.
2. Non-obstructive atelectasis
Seen in the reduction of lung ventilation, alveolar smooth muscle elastic fiber sputum and lack of surfactant activity of alveolar surface tension.
Prevention
Pediatric atelectasis prevention
Mainly to prevent respiratory infections and inhalation of foreign bodies. One of the effective ways to prevent upper respiratory tract infections in children is to improve the immunity of the child's respiratory tract and enhance the child's resistance to pathogens. Promote breastfeeding. Breast milk is the ideal natural food for babies and contains a variety of nutrients. Breast milk contains a large amount of immunoglobulins, immune cells, lysozyme, lactoferrin, etc., which helps to improve the anti-infective ability of infants. Especially the colostrum originally secreted after childbirth, rich in antibodies and trace elements, especially SIGA helps prevent respiratory and gastrointestinal infections.
Complication
Pediatric atelectasis complications Complications emphysema bronchiectasis
Excessive expansion of modern compensatory alveolar, severe emphysema, such as chronic atelectasis, easily secondary infection on the basis of atelectasis, resulting in bronchial damage and inflammatory secretion retention, bronchiectasis can occur over time And lung abscess or pulmonary fibrosis.
Symptom
Pediatric atelectasis symptoms common symptoms dyspnea, snoring, hypoxemia, atelectasis, high fever, chest pain, recurrent edema, intersegmental displacement
1. Symptoms and signs
Because of the different causes and sizes, the performance is also different. The different degrees of atelectasis are described below.
(1) one or both of the atelectasis: often caused by a variety of reasons, such as the pectoral muscle, diaphragmatic paralysis cough reflex and bronchial endocrine obstruction, one or both sides of the atelectasis, the onset is very urgent, Breathing is extremely difficult. Older children can complain of chest pain and palpitations. They can have high fever, pulse rate and cyanosis. They occur in the latter part of the operation. They occur within 24 hours after surgery. The obvious chest signs are as follows: 1 The ipsilateral thorax is flat and breathing. Exercise was restricted, 2 trachea and apex beat to the disease side, 3 slight dullness during percussion, but on the left side can be covered by the rising stomach, 4 tremors and respiratory sounds weak or disappear, 5 diaphragm muscle elevation.
(2) lobary atelectasis: slow onset, less difficult to breathe, signs similar to unilateral atelectasis, but to a lesser extent, can vary with the lobe of the lobe, upper lobe atelectasis When the trachea moves to the diseased side and the heart does not shift, the percussive dullness is limited to the front chest; when the inferior lobe is inferior, the trachea does not shift and the heart moves to the diseased side, and the percussive dullness is located at the back of the spine; Signs are less, difficult to detect, due to compensatory emphysema in the adjacent area, percussion dullness is often not obvious.
(3) Lung incarceration: very few clinical symptoms, not easy to detect, atelectasis can occur in any lobe or lung segment, but the left upper lobe is the most rare, only in congenital heart disease, the enlarged left pulmonary artery oppresses the left upper lobe The bronchus can cause left atelectasis atelectasis. Pediatric atelectasis is most common in the lower lung and right middle lobe. At lower respiratory tract infection, atelectasis is more common in the lower left and right middle leaves. Tuberculous enlarged lymph nodes cause upper right and right Middle lobe syndrome, "middlelobe syndrome" refers to the atelectasis caused by tuberculosis, inflammation, asthma or tumors, does not disappear for a long time, repeated infections, and finally develops into bronchiectasis.
2. Pulmonary function test
It can be seen that pulmonary functional capacity reduces lung compliance, abnormal ventilation/blood flow ratio, and arteriovenous shunts with varying degrees of severity, hypoxemia, and the like.
3. X-ray inspection
X-ray features uniform and dense shadows, occupying one side of the chest, one leaf or lung segment, no shadow structure, lung texture disappearing and lung volume shrinking, and one side or large piece of atelectasis can be narrowed and the thoracic cavity is narrowed (Fig. 1B). ), the position of the shadow varies with the location of the atelectasis of each lobe. The atelectasis of the lower lobe is triangularly shadowed in the frontal chest radiograph, located between the spine and the diaphragm, and close to the posterior chest wall in the lateral patch. If there is no extension, the front side and the side shadows are wedge-shaped. The tip is downward and points to the hilum. If the left middle lobe is atelectasis (Fig. 1C), the frontal shadow is triangular, and the bottom is at the right edge of the heart. Pointing to the outside; its silhouette is a wedge shape, the bottom is near the front chest wall, above the diaphragm, the tip is backward and upward, in the infant period, in addition to compensatory emphysema, other compensatory phenomena such as tracheal and cardiac displacement and The diaphragmatic muscle rises, but it does not appear until the atelectasis persists for a long time. However, due to the lack of surface active substances, the lungs are mostly with a glassy shadow, and the X-ray findings are no different from those of lobular pneumonia.
4. Course of disease
Obstructive atelectasis can be transient or persistent, pneumonia, bronchiolitis, asthma and bronchitis caused by mucin embolism or mucosal edema, atelectasis, shorter time, disappeared after inflammation and swelling, due to tuberculosis or not When the foreign body is removed, the atelectasis can be relatively long-lasting, and bilateral or large areas of atelectasis often die rapidly. The bronchoscope should be used to immediately aspirate the blockage and survive by artificial respiration.
Examine
Pediatric atelectasis
Blood picture
Infected or complicated by infection, may have the characteristics of infectious blood.
2. Blood gas analysis
Have hypoxemia and so on.
3. Other
Caused by tuberculosis, increased erythrocyte sedimentation rate, positive tuberculin test, etc.; increased serotonin in serum and urine, which contributes to the diagnosis of atelectasis caused by bronchial carcinoid.
Inspection diagnosis
X-ray inspection
X-ray chest radiograph shows uniform and dense shadow, occupying one side of the chest or one leaf or lung segment, the shadow has no structure, the lung texture disappears and the lung leaf volume shrinks. In the early stage of "flooding lung", the chest radiograph shows the extension of interlobular fissure. The segmental or lobes increased in volume, and the pleural line became convex from a normal straight line; after 36 hours, the indwelling area collapsed, and the interlobular fissure was concave, most typically the right middle lobe was atelectasis, and the collapse became a close-knit band. It is easy to be misdiagnosed as pleural thickening. One side of atelectasis is caused by complete obstruction of unilateral main bronchus. The affected lung field is evenly densely shadowed. At the same time, the thoracic cavity is collapsed, the intercostal space is narrow, the trachea, mediastinum and heart are displaced to the affected side. The diaphragmatic rise, the compensatory emphysema of the contralateral lung, the lobules of atelectasis, caused by the complete obstruction of the lobes of the lungs, the volume of the lungs is reduced, the dense and uniform shadow, the interstitial shift of the leaf space, the right lung When the upper lobe is infertile, the posterior anterior chest radiograph shows an increase in the density of the right upper lobe, the lateral fissure is shifted outward, the upper lobe is reduced in volume and is folded in a fan shape, and the slightly contracted upper lobe is curved in a concave downward direction; The contracted upper lobe can be expressed as the tip of the mediastinum The basal, basement is located in the triangular dense shadow of the tip of the lung. The lung texture of the middle and lower lobe is obviously moved up and evacuated. The hilar is raised, the compensatory emphysema occurs in the middle and lower lobe, the trachea can be moved to the right, and the left upper lobe includes the tongue. Leaves, so the upper part is thick and the lower part is thin. When it is not open, the posterior anterior piece appears as a blurred shadow in the middle lung field of the left lung. The upper part has a higher density and the lower part is lighter, and there is no clear boundary. The trachea is shifted to the left and the lateral position. The slice is displaced obliquely forward, the lower lobe is compensatory emphysema, and the dorsal segment can be expanded upwards to the level of the second thoracic vertebra. When the right middle lobe is atelectasis, the posterior anterior slice shows the lower right hilar. Flakyly blurred shadow, tip to lung field, base in the narrowed triangle of the hilar, lateral position as a strip from the lung door forward and downward, or a long triangular shadow from the tip to the hilum, atelectasis on both sides of the lung At the same time, the X-ray performance is similar, that is, there is a tip on the inside of the lower lungs, a dense triangular shadow on the base, a shadow shift of the hilar, a compensatory emphysema in the upper middle lobe, an evacuation of the lung texture, and a right lung. The inferior lobe of the lower lobe is clearer than the left side, and the inferior left lobe can be due to the weight of the heart. Stacked and unclear, often seen on X-ray films in oblique or overexposed conditions, inferior inferior lobe in lateral position, oblique shift to posterior inferior, lower translucent in lower lobe, large lobar Incomplete, often accompanied by different degrees of subsequent findings, such as stenosis of the lateral intercostal space, the ipsilateral sacral rise when the lower lobe collapses, the upper lobe of the atelectasis has a hilar up, and the lower lobe of the atelectasis moves down (Normally, the left hilar is slightly higher than the right side); the mediastinum and the contour of the heart are displaced to the case. The mediastinal structure of the infant is elastic, especially obvious. The atelectasis of the upper lobe is displaced to the disease side in children and adults. However, the baby's normal trachea is longer and bends to the right. Therefore, if the tracheal displacement is seen alone, the diagnosis in infancy is of little significance. Some healthy lungs and contralateral lungs on the disease side present compensatory emphysema, and the brightness is enhanced. Common contralateral lungs are removed from the mediastinum to the affected side. The segmental posterior lobe usually has a wedge-shaped dense shadow. The tip is toward the hilum, the base is outward, the lung segment is reduced in volume, and the sub segmental lung is not. Zhang is in the form of a sheet, the X-ray is horizontal, and is located above the Henglong, the positive side. It can be seen that in the onset of asthma, there are many segmental atelectasis, diffuse strip shadows, easy to be mistaken for pneumonia, after 1 to 2 days of asthma is controlled, then the film is seen disappearing, round Discoid lung atelectasis is not common, it is spiral, X-ray is round, oval, angular or comma-shaped, mostly occurs in the base of the lung, secondary to pleural effusion or therapeutic pneumothorax, so often accompanied by pleura Hypertrophy, rib angle becomes dull, half of the chest cavity collapses or pleural calcification, must be differentiated from malignant tumors, transparent membrane disease is a typical reticulated granule, which is excessive expansion of small airway and air gap, if it is uniform opaque area , indicating the enlargement of the atelectasis.
2. Pulmonary function test
It can be seen that the lung capacity is reduced, the lung compliance is decreased, the ratio of ventilation/blood flow is abnormal, and the degree of arteriovenous shunt is different, such as hypoxemia.
3.CT scan
Thoracic CT scan of the chest showed atelectasis.
4. Fiberoptic bronchoscopy
The obstruction site can be clearly defined, and the cytology and histological examination can be performed. The bacterial quantitative culture and drug sensitivity analysis can be performed, and the topical drug can be used for diagnosis and treatment.
Diagnosis
Diagnosis and diagnosis of pediatric atelectasis
X-ray examination plays a major role in diagnosis, especially in perspective, but it is limited to a lobe of atelectasis. Sometimes it is difficult to distinguish it from pneumonia. It should be considered with reference to the anatomical position of the lung lobe. If necessary, bronchoscopy can be performed to determine the obstruction. The location and nature, as well as appropriate treatment.
It should be differentiated from pneumonia, pleural effusion and pulmonary embolism. It is not difficult to use. X-ray positive lateral radiograph can help to confirm the diagnosis.
