Pediatric bronchiectasis

　　I. Etiology

　　Bronchiectasis can be divided into two major categories: congenital and acquired.

　　1. Congenital bronchiectasis

　　Rarely seen, it can be caused by developmental defects of bronchial cartilage, seen in infants; or due to developmental defects of tracheobronchial muscles and elastic fibers, leading to giant tracheobronchomegaly, seen in older children.

　　2. Congenital bronchiectasis

　　Commonly seen in measles, pertussis, bronchiolitis, and severe pneumonia, especially with severe pneumonia caused by adenovirus types 21, 7, and 3. Asthma is also common, and bronchiectasis caused by such etiologies is often bilateral and diffuse. If bronchiectasis is caused by foreign body obstruction, bronchial lymph node tuberculosis, or tumor compression, or by bronchial tuberculosis complicated with long-standing atelectasis, it is usually localized. Bronchiectasis is related to some specific defense function defects of the body. These mainly include defects in humoral immunity, local immune defense, and immune disorders. Among them, the most common are patients with humoral immunity defects, such as X-linked agammaglobulinemia, common variable immunodeficiency disease, and IgG subclass defects, which are also one of the causes of bronchiectasis. Local immune defense defects, such as primary ciliary dyskinesia, can lead to reduced mucociliary clearance function due to poor ciliary movement. Additionally, benign or malignant tumors, ossification of the ribs, or compression by bone spurs can also cause bronchiectasis.

　　2. Pathogenesis

　　The two fundamental pathogenic factors are infection and bronchial obstruction, which mutually reinforce each other. Due to bronchial obstruction, the retained secretions in the lumen exert pressure on the softened bronchial wall damaged by inflammation, leading to obstruction over time and far-end bronchiectasis. At the same time, infection can cause severe cough, increasing the intrabronchial pressure and promoting bronchiectasis. In addition, the presence of pulmonary consolidation or atelectasis for a long time, leading to fibrosis and scar contraction of the lung tissue, can also cause bronchi to be stretched, twisted, and displaced, which are factors contributing to bronchiectasis.

　　The areas of atelectasis and the dilated bronchi are prone to recurrent infections, with varying degrees of severity. Mild cases may only present with low-grade fever and increased sputum production, while severe cases may develop pneumonia and lung abscesses. Bronchiectasis often leads to pneumonia, lung abscess, lung gangrene, empyema, and pyopneumothorax due to concurrent pyogenic bacterial infection. When widespread fibrosis occurs in the lung tissue and the pulmonary capillary bed is severely damaged, it can lead to increased pulmonary artery circulation resistance, pulmonary hypertension, and chronic pulmonary heart disease.

　　1. Main symptoms

　　Main symptoms include cough, profuse sputum, more common after waking up in the morning or changing positions. The amount of sputum can vary, with thick, purulent sputum and a slight odor. Irregular fever is not uncommon, and patients with a long course of the disease may experience varying degrees of hemoptysis, anemia, and malnutrition. Patients are prone to upper and lower respiratory tract infections, often suffering from recurrent pneumonia, even complicated with lung abscesses, usually confined to the same lesion site.

　　2. Chest signs

　　Similar to pneumonia, but with varying degrees of severity. Sometimes, auscultation yields nothing, but most often, wet rales can be heard at the base of the lungs, with a relatively fixed location. If the affected area is extensive, the mediastinum and heart may shift to the affected side due to atelectasis or fibrotic changes. Children with malnutrition and poor development may have chest deformities, clubbing of the fingers and toes, which can appear at different times, with the earliest occurring within 1 to 2 months. They can naturally disappear after surgical resection of the affected lung lobe. Maxillary sinusitis is common. If the condition continues to worsen, liver enlargement and proteinuria may be observed, as well as complications such as amyloidosis and hypertrophic pulmonary osteoarthropathy.

　　The pneumonia child should be followed up carefully until complete recovery. Timely treatment of bronchial lymph node tuberculosis and early removal of bronchial foreign bodies are measures to prevent bronchiectasis. Prevention and treatment of measles, pertussis, bronchopneumonia, and pulmonary tuberculosis, and other acute and chronic respiratory tract infections are of great significance for the prevention of bronchiectasis. Bronchiectasis patients should actively prevent respiratory tract infections, persist in body position expectoration, enhance the body's immune function to improve the body's ability to resist diseases.

　　1. X-ray examination

　　At a mild stage, only the lung markings are intensified, and when the lesions are obvious, the lower lungs can show annular or honeycomb-like translucent shadows in a curly or honeycomb-like pattern, often accompanied by atelectasis of the lung segment or lobe and inflammatory infiltration shadows. The heart and mediastinum can be seen to be displaced, and bronchiectasis and deformation can be seen on the tomographic X-ray.

　　2. Bronchial angiography

　　It can show the bronchus in a columnar, fusiform, or cystic dilatation, clearly defining the morphology, location, and scope of bronchiectasis. Good preoperative preparation should be made during the angiography, to prevent accidental asphyxia, and fasting is required before the operation to prevent vomiting. After the operation, magnesium sulfate should be given to excrete the iodine oil in the stomach, to avoid iodine poisoning.

　　3. CT examination

　　In recent years, high-resolution CT has replaced bronchial angiography, which is safe and reliable, simple and easy to perform, and has the same sensitivity and specificity as bronchial angiography, and has become the main examination method for diagnosing bronchiectasis.

　　1. Avoid fried and spicy刺激性 foods

　　Fried and greasy foods are not easy to digest and can produce internal heat,煎熬 body fluids, which can help moisten phlegm, block the lung tract, and lead to increased cough and asthma. Spicy foods such as chili, onions, garlic, and pepper can produce heat and phlegm after eating, and can also stimulate the bronchial mucosa, causing local edema and exacerbating cough and asthma. Therefore, chronic bronchitis patients should avoid eating fried and spicy刺激性 foods.

　　2. Avoid smoking

　　The harmful substances in cigarettes can directly stimulate the respiratory tract. Cigarettes are not only an important cause of chronic bronchitis in smokers themselves, but the smoke can also bring harm to the health of the respiratory tract of the surrounding people. Therefore, chronic bronchitis patients should completely quit smoking.

　　3. Avoid cold and cool foods

　　Chronic bronchitis patients have a long course of illness, most of them have insufficient Yang in the spleen, lung, and kidney, and have a strong reaction to cold and cool foods. Because coldness is condensing, and coldness mainly leads to contraction, excessive intake of cold and cool foods can cause tracheal spasm, which is not conducive to the excretion of sputum, thereby aggravating cough and asthma, making it difficult to cough out sputum. In addition, cold and cool foods damage the Yang of the spleen and stomach, and when the spleen and stomach are attacked by coldness, the transformation and transportation function is impaired, leading to endogenous phlegm turbidity, blocking the respiratory tract, and exacerbating cough and asthma. Therefore, chronic bronchitis patients should eat less cold and cool foods.

　　4. Avoid seafood and other irritants

　　Allergic reactions are one of the causes of chronic bronchitis, and fish, shrimp, salmon, yellow croaker, hairtail, herring, smelt, crab, and poultry eggs, fresh milk or dairy products are common allergens. Therefore, patients with chronic bronchitis should avoid eating such foods. In addition, they should also avoid drinking alcohol, eating eggs, pumpkin, mustard greens, rice lees, rapini, sake, and other foods.

　　1. Treatment

　　In addition to paying attention to fresh air, rest, and nutrition, the main thing is to eliminate inflammation, ensure adequate drainage, maintain the patency of the respiratory tract, and will be described as follows.

　　1. Remove the cause of disease and exclude bronchial secretions

　　For those with airway obstruction caused by various reasons, the etiology should be removed in a timely manner. It was previously believed that bronchiectasis was irreversible, but there are cases that have been confirmed, even if bronchiectasis has formed, after removing the obstruction, after sufficient conservative treatment such as anti-infection and pulmonary physiotherapy, the expanded bronchi may be repaired again, and pulmonary inflammation can also disappear without surgery. For the excretion of bronchial secretions, the method of sequential expectoration can be used, taking different sequential positions for different areas and performing expectoration twice a day for 20 minutes each time. If the secretions are too thick, it is advisable to take potassium iodide or ipecac syrup or traditional Chinese and Western medicine for expectoration, or use nebulization inhalation to humidify the respiratory tract first, then perform sequential expectoration, back tapping, and sputum aspiration, which makes the sputum easier to be excreted, which is very important. In recent years, Beijing Children's Hospital has had good effects on expectoration using bronchoalveolar lavage technique.

　　2. Antimicrobial drugs

　　In the acute exacerbation phase, the use of Chinese and Western medicine to control infection is recommended. The key to treatment lies in inhibiting the growth of pathogenic microorganisms and the release of mediators. During acute infection of bronchiectasis, since the bacterial population infected with the trachea is usually the same as that in patients with chronic bronchitis, effective antibiotics against Streptococcus pneumoniae and Haemophilus influenzae are the first choice, such as amoxicillin, trimethoprim-sulfamethoxazole, and new macrolide drugs such as clarithromycin, azithromycin, and second-generation cephalosporins are reasonable choices. The duration of treatment is not fixed, but at least 7 to 10 days. The principle of using antibiotics to prevent infection is: low dose, short course, and narrow spectrum. Once resistance occurs, timely drug replacement should be done, and non-oral administration should be used. Commonly used antibiotics include aqueous penicillin, with a total daily dose of about 1 to 3 million units, which can be administered by intramuscular or intravenous injection, with a course of about 2 weeks. Penicillin nebulization can also be added, with 200,000 units dissolved in 10ml of distilled water, inhaled within 10 minutes, repeated 3 to 4 times a day, for 1 to 2 weeks. It can also be used in combination with streptomycin. Later, according to the results of bacterial culture and antibiotic sensitivity testing, cephalosporins or other antibacterial drugs should be replaced. Antibacterial drugs should also be used before and after surgical treatment. Common Chinese herbal medicine for clearing heat and detoxifying is Dandelion, Isatis root. Herbs such as Lonicera, Forsythia, Houttuynia, and Isatis leaf, in the convalescent period, should be added Astragalus, Codonopsis, and Angelica for weak children.

　　3. Human blood gamma globulin

　　For patients with low human blood gamma globulin, human blood gamma globulin replacement therapy can reduce the occurrence of deformed respiratory bacterial infections and prevent the progression of bronchiectasis lesions. In patients with X-linked low human blood gamma globulin and common variant immunodeficiency disease, early use of human blood gamma globulin replacement therapy after diagnosis can effectively prevent the formation of bronchiectasis by keeping the level of IgG in the blood greater than 5g/L.

　　4. Surgical treatment

　　(1) Lung resection: This is the fundamental therapy, but it is necessary to pay attention to preoperative medical treatment, apply strong antibiotics and bronchodilators to reduce bacterial infections and promote sputum drainage, and prepare for surgery. The indications for surgery are: ① After 9 to 12 months of medical treatment, still ineffective. ② Severe cases limited to one lobe or one side. ③ Repeated hemoptysis, difficult to control, and resection of the airway part that cannot be controlled by bleeding. ④ Recurrent severe infections in the disease area, and drug treatment is difficult or there may be drug-resistant microorganisms such as Aspergillus. ⑤ Children who do not cooperate with sputum expectoration. ⑥ The general health condition of children is deteriorating. In recent years, due to the progress of thoracic surgery, postoperative complications and mortality rates have been greatly reduced, so it is generally advocated that children with the above indications can strive for early surgery under reliable thoracic surgical conditions. Patients under 9 years of age generally undergo careful medical treatment first to lay the foundation for future surgical treatment.

　　(2) Lung transplantation: For patients with severe and extensive pulmonary lesions and severe clinical symptoms, lung transplantation may be the last resort for treatment.

　　II. Prognosis

　　After the widespread application of antibacterial drugs, bacterial lung infections are more easily controlled, but if treatment is not timely, it can still be accompanied by lung abscess, emphysema, massive hemoptysis, and even sepsis. Localized lesions have a good long-term prognosis; while patients with asthma and bilateral bronchiectasis lesions, as well as those with Pseudomonas aeruginosa and fungal infections, have a poor prognosis. The severity of pulmonary lesions shown by CT is closely related to whether the patient's treatment can proceed smoothly, and the forced expiratory volume in one second (FEV1) / forced vital capacity (FVC) is helpful in predicting the prognosis of surgery.