Preface This guideline is based on the “Routine for the Prevention and Treatment of Bronchial Asthma in Children (Trial)” revised in 2003 in China, re-revised with reference to the asthma prevention and treatment guidelines and evidence-based medical evidence published in recent years at home and abroad, and re-revised with the characteristics of pediatric clinical practice in China, to provide guiding recommendations for the standardized diagnosis and prevention of asthma in children.
[Definition]
Bronchial asthma is a chronic inflammatory disease of the airways involving multiple cells, including inflammatory cells (eosinophils, mast cells, T lymphocytes, neutrophils, etc.), airway structural cells (airway smooth muscle cells and epithelial cells, etc.) and cellular components.
This chronic inflammation leads to airway hyperresponsiveness in susceptible individuals, and when exposed to physical, chemical, and biological stimuli, widespread and variable reversible airflow limitation occurs, resulting in recurrent episodes of wheezing, coughing, shortness of breath, and chest tightness, often occurring or worsening at night and/or early in the morning, and resolving with treatment or on its own in most children.
[Diagnosis]
Children are in the process of growth and development, and the diagnosis and treatment of asthma differ among children of all ages due to the different anatomical, physiological, immunological and pathological characteristics of the respiratory system, the different clinical phenotypes of asthma, the different response to medication and the degree of coordination and cooperation, etc.
I. Diagnostic criteria
1. Recurrent attacks of wheezing, cough, shortness of breath and chest tightness, mostly related to exposure to allergens, cold air, physical and chemical stimuli, respiratory tract infections and exercise, etc., often occurring or intensifying at night and/or early in the morning.
2.Dispersive or diffuse, expiratory-phase croup can be heard in both lungs during the attack, with prolonged expiratory phase.
3.The above signs and symptoms are effective with anti-asthma treatment or resolve on their own.
4.Except wheezing, cough, shortness of breath and chest tightness caused by other diseases.
5.In case of atypical clinical manifestations (such as no obvious wheezing or croup), at least 1 of the following should be present.
(1) Positive bronchial excitation test or motor excitation test;
(2) Confirmation of the presence of reversible airflow limitation.
(1) Positive bronchodilator test: ≥ 12% increase in first second exertional expiratory volume (FEV1) 15 min after inhalation of a fast-acting β2 agonist [e.g., salbutamol] or
(2) effective anti-asthma treatment: ≥ 12% increase in FEV1 after 1-2 weeks of treatment with bronchodilators and oral (or inhaled) glucocorticoids; (3) 20% daily variability (continuous monitoring for 1 to 2 weeks) in maximum expiratory flow (PEF).
Those who meet Articles 1 to 4 or 4 and 5 can be diagnosed as asthma.
II. Characteristics of wheezing in children under 5 years old
1. Clinical phenotype and natural course of wheezing in children under 5 years of age: wheezing is a very common clinical manifestation in preschool children, and recurrent wheezing can occur in non-asthmatic preschool children. Wheezing in children under 5 years of age can be classified into 3 clinical phenotypes.
(1) Early transient wheezing: Mostly seen in premature births and parental smokers, wheezing is mainly due to environmental factors causing delayed lung development, with age leading to gradual maturation of lung development, and most children with wheezing gradually disappearing within 3 years of birth.
(2) Persistent wheezing with early onset (before the age of 3 years): Children mainly present with recurrent wheezing associated with acute respiratory viral infections, with no atopic manifestations or family history of allergic diseases. Wheezing symptoms usually persist until school age, and some children remain symptomatic at 12 years of age. In children younger than 2 years of age, the cause of wheezing episodes is usually associated with infections such as respiratory syncytial virus, and in children older than 2 years of age, it is often associated with other viral infections such as rhinovirus.
(3) Delayed wheezing/asthma: These children have a typical atopic background, often with eczema, and asthma symptoms often extend and persist into adulthood, with typical asthma pathology in the airways.
It should be noted, however, that types 1 and 2 of childhood wheeze can only be identified by retrospective analysis. Early intervention in childhood wheezing facilitates disease control and therefore it is not advisable to classify patients as such at the time of initial treatment.
Evaluation of wheezing in children under 5 years of age: More than 80% of asthma starts before the age of 3 years, and in patients with persistent asthma with pulmonary impairment, the impairment often starts in preschool, so it is necessary to identify children who are likely to develop persistent asthma from among wheezing preschoolers for effective early intervention. However, there are no specific tests or indicators that can be used to make a definitive diagnosis of asthma in preschool wheezing children.
The diagnosis of asthma is highly suggested in wheezing children who have the following clinical features.
(1) Frequent episodes of wheezing more than once a month;
(2) Activity-induced cough or wheeze;
(3) intermittent nocturnal cough not caused by a viral infection; (4) wheezing symptoms that persist beyond 3 years of age.
The Asthma Predictor Index can be used effectively to predict the risk of developing persistent asthma in wheezing children within 3 years of age. Asthma prediction index: ≥4 wheezing episodes in the past 1 year, with 1 major risk factor or 2 minor risk factors.
Major risk factors included.
(1) Parental history of asthma;
(2) diagnosis of atopic dermatitis by a physician;
(3) evidence of sensitization to inhaled allergens.
Secondary risk factors include.
(1) Evidence of food allergen sensitization;
(2) Peripheral blood eosinophils ≥ 4%;
(3) wheezing unrelated to cold. If the asthma prediction index is positive, standardized treatment of asthma is recommended.
Despite the possibility of overtreatment, antiasthmatic medication significantly reduces the severity and duration of wheezing episodes in preschool children compared with the use of antibiotics. Therefore, diagnostic treatment with anti-asthmatic medication for 2 to 6 weeks is recommended for re-evaluation in preschoolers with recurrent wheezing for which antibiotic therapy has not been effective. It must be emphasized that the majority of preschool children with wheezing have a good prognosis and their asthma-like symptoms may resolve spontaneously with age. Therefore, these children must be reevaluated periodically (3 to 6 months) to determine the need for continued antiasthmatic therapy.
III. Diagnosis of cough variant asthma
Cough variant asthma (CVA) is one of the most common causes of chronic cough in children, with cough as the only or main manifestation, without significant wheezing.
Diagnosis is based on.
(1) Cough lasting >4 weeks, often with episodes or exacerbations at night and/or early in the morning, with a predominantly dry cough;
(2) No clinical signs of infection, or ineffective with prolonged antibiotic therapy;
(3) Diagnostic treatment with anti-asthmatic drugs is effective;
(4) other causes of chronic cough are excluded;
(5) Positive bronchial excitation test and/or PEF daily variability (continuous monitoring for 1 to 2 weeks) ≥ 20%;
(6) Personal or first- or second-degree relative history of atopic disease, or positive allergen test.
The above 1~4 items are the basic conditions for diagnosis.
4.Related tests for asthma diagnosis and condition monitoring and evaluation
1.Pulmonary function test: Pulmonary function measurement helps to confirm the diagnosis of asthma and is one of the important bases for assessing the severity and control level of asthma. For children with suspected asthma with FEV1 ≥ 70% of the normal expected value, bronchial excitation test can be selected to determine airway reactivity, and for children with suspected asthma with FEV1 < 70% of the normal expected value, bronchial diastolic test can be selected to assess the reversibility of airflow limitation. confirm the diagnosis of asthma.
2. Allergy status testing: inhalation allergen sensitization is a major risk factor for the development of persistent asthma in children, and early food sensitization in children increases the risk of inhalation allergen sensitization and predicts the development of persistent asthma. Therefore, allergen skin prick test or serum allergen-specific IgE assay is recommended for all children with recurrent wheezing suspected of asthma, especially preschool children who cannot cooperate with pulmonary function testing, to understand the patient’s allergic status and to assist in the diagnosis of asthma.
It is also useful to understand the individual risk factors that contribute to the onset and exacerbation of asthma and helps to develop environmental interventions and determine allergen-specific immunotherapy regimens.
3. Airway noninvasive inflammatory index testing: sputum or induced sputum levels of eosinophils and exhaled breath nitric oxide (FeNO) can be used as asthma airway inflammatory indexes. Although there are no prospective studies to confirm the exact value of these noninvasive inflammatory indicators in the diagnosis of asthma in children, the monitoring of these indicators can help to assess the level of asthma control and to develop the optimal asthma treatment plan.
[Staging and grading]
I. Staging
Asthma can be divided into three phases: acute exacerbation, chronic persistent, and clinical remission. Acute exacerbation refers to the sudden onset of wheezing, coughing, shortness of breath, chest tightness and other symptoms, or a sharp aggravation of the original symptoms; chronic persistent refers to the occurrence of wheezing, coughing, shortness of breath, chest tightness and other symptoms with different frequencies and/or degrees in the past 3 months; clinical remission refers to the disappearance of symptoms and signs with or without treatment, and the recovery of lung function to the level before the acute exacerbation, and maintenance for more than 3 months.
Grading
The grading of asthma includes the grading of severity, the grading of asthma control level and the grading of acute attack severity.
1.Grading of severity of disease: The grading of severity of disease is mainly used for the first diagnosis and for children who have been diagnosed but not yet treated according to the standard asthma treatment, and is used as a basis for setting the level of starting treatment plan.
2.Grading of control level: Asthma control level is used to assess whether children with standardized asthma treatment have achieved the asthma treatment goal and to guide the adjustment of the treatment plan to achieve and maintain asthma control. Long-term asthma treatment regimens dominated by asthma control levels can lead to more adequate treatment and clinical control in most asthma patients (Table 2).
3. Acute asthma attack severity grading: Acute asthma attacks often show a progressive exacerbation process, characterized by reduced expiratory flow, and are often triggered by exposure to allergens, irritants or respiratory infections. It may occur within hours or days, or occasionally within minutes, and is life-threatening. Therefore, the condition should be properly evaluated in order to provide timely and effective emergency treatment. The severity of an acute asthma attack is graded.
[Treatment]
I. Objectives of treatment
(1) To achieve and maintain symptom control;
(2) To maintain normal activity, including exercise capacity;
(3) To bring lung function levels as close to normal as possible;
(4) To prevent acute asthma attacks;
(5) avoiding adverse reactions due to asthma medication;
(6) Prevent death caused by asthma.
II. Prevention and control principles
Asthma control treatment should be as early as possible. The principles of long-term, continuous, standardized and individualized treatment should be adhered to.
Treatment includes.
(1) Acute exacerbation: rapid relief of symptoms, such as wheezing and anti-inflammatory treatment;
(2) chronic persistence and clinical remission: prevent symptom exacerbation and relapse, such as avoiding triggers, anti-inflammatory, reducing airway hyperresponsiveness, preventing airway remodeling, and good self-management.
The combination of pharmacological and non-pharmacological treatments should be emphasized, and the role of non-pharmacological treatments such as education on asthma prevention and treatment, allergen avoidance, management of psychological problems of children, improvement of quality of life, pharmacoeconomics and other aspects in long-term management of asthma should not be neglected.
III. Long-term treatment plan
According to the age, there are long-term treatment programs for asthma in children aged 5 years and above and long-term treatment programs for asthma in children under 5 years. Long-term treatment regimens are divided into 5 levels, and different asthma control medications are available in the regimens from level 2 to level 5. Children with previously untreated primary asthma were selected for the Level 2, Level 3, or Level 4 regimens, depending on the severity of the disease. In all levels of treatment, the treatment regimen was reviewed every 1 to 3 months and adjusted appropriately according to the control of the disease.
If asthma is controlled and maintained for at least 3 months, the treatment regimen may be considered for downgrading until the minimum dose to maintain asthma control is determined. If partially controlled, escalation of therapy may be considered to achieve control. However, the child’s aspiration technique, adherence to the dosing regimen, allergen avoidance, and other triggers should first be checked before escalating therapy. If not controlled, escalate or step up treatment until control is achieved.
In the long-term treatment regimen for childhood asthma, in addition to the regular daily use of control therapy medications, relief medications are used as needed depending on the condition. Inhaled rapid-acting β2 agonists are currently the most effective relievers and are the first choice for acute asthma in children of all ages, usually no more than 3 to 4 times in 1 d. Combined inhalation of anticholinergic drugs is also an option as a palliative drug. children 5 years and older can be treated with a single inhaler containing formoterol and budesonide as a control and palliative drug.
Long-term treatment options for asthma in children aged 1.5 years and older; China has a wide geographic area and very uneven socioeconomic development, so the choice of combination therapy requires consideration of both regional and economic differences in addition to efficacy. It must be emphasized that inhaled long-acting β2 agonists (LABA) should not be used as monotherapy at any age, but only as combination therapy when using moderate amounts of inhaled glucocorticoids (ICS).
2. Long-term treatment options for asthma in children under 5 years of age: For the long-term treatment of asthma in children under 5 years of age, the most effective therapeutic agent is ICS. Low-dose ICS (Tier 2) is recommended as initial control therapy for most children. If low-dose ICS does not control symptoms, increasing the dose of ICS is the best option. Leukotriene receptor antagonists (LTRA) may be used in children who are unable or unwilling to use ICS, or who have allergic rhinitis.
Oral extended-release theophylline has some efficacy in the long-term treatment of asthma in children under 5 years of age, and its use should not be completely abandoned clinically; however, theophylline is less effective than low-dose ICS, and the adverse effects are more significant. LABA or combination formulations have not been adequately studied in children under 5 years of age.
IV. Treatment of acute exacerbations
Treatment is individualized on an as-is basis, depending primarily on the severity of the acute attack and response to initial therapeutic measures. The process of hospital treatment for acute asthma exacerbation is described in [Annex 1].
If an acute asthma attack is treated with asthma relieving drugs such as bronchodilators and glucocorticoids with reasonable application, but still has severe or progressive dyspnea, it is called asthma critical state (asthma persistent state).
If the bronchial obstruction is not relieved in time, it can rapidly develop into respiratory failure and become a direct threat to life, which is then called life-threatening asthma attack (1ife threatening asthma). Any child with critical asthma should be placed in a good medical environment, provided with oxygen to maintain oxygen saturation above 0.92-0.95, monitored with cardiopulmonary monitoring, blood gas analysis and ventilation function, and sedation is prohibited for those who are not extubated.
1, inhaled rapid-acting β2 agonist: use oxygen-driven (oxygen flow 6-8L/min) or air compression pump nebulized inhalation, the first hour can be every 20 minutes once, and then repeat inhalation treatment every 1-4 hours according to the condition; drug dose: each inhalation salbutamol 2.5-5mg or Terbutalin (Terbutalin) 5-10mg. if no nebulized inhaler, can Use pressure type quantitative aerosol (pMDI) through the fog storage tank inhalation, each time a single dose of spray, continuous use of 4 ~ 10 spray, the medication interval and nebulized inhalation method is the same.
If there is no condition to use inhaled rapid-acting β2 agonist, subcutaneous injection of epinephrine can be used, but clinical observation should be strengthened to prevent the occurrence of cardiovascular and other adverse reactions. Drug dose: 1:1000 epinephrine 0.01 ml/kg per subcutaneous injection, the maximum dose should not exceed 0.3 ml. If necessary, it can be injected once every 20 minutes, but not more than 3 times.
If treatment with inhaled rapid-acting β2 agonists is ineffective, intravenous application of β2 agonists may be required. Drug dose: salbutamol 15μg/kg slowly intravenously for more than 10min; the dose is 1~2μg/(kg-min) [≤5μg/(kg-min)] for severe disease requiring intravenous maintenance drip. When applying β2 agonist intravenously, serious adverse reactions such as arrhythmia and hypokalemia are likely to occur, so it is necessary to strictly control the indications and dose, and make necessary monitoring of electrocardiogram, blood gas and electrolytes.
2.Glucocorticoid: Systemic application of glucocorticoid is the first-line drug for the treatment of severe asthma attack in children, and its early use can reduce the severity of the disease and show obvious efficacy 3-4 hours after administration. Drug dose: oral prednisone 1~2mg/(kg-d). Children with severe disease can receive intravenous hydrocortisone succinate 5-10mg/(kg-d) or methylprednisolone 1-2mg/(kg-d), which can be repeated at 4-8h intervals depending on the disease.
High-dose ICS is helpful in the treatment of asthma attacks in children, and nebulized inhalation of budesonide suspension 1mg/time is selected and used once every 6-8 hours. However, in severe cases, inhalation therapy should not replace systemic glucocorticoid therapy to avoid delaying the disease.
3.Anti-cholinergic drugs: They are an integral part of the combination therapy for critical asthma in children, and their clinical safety and efficacy have been established. They should be used in combination as early as possible in severe cases that do not respond well to β2 agonist therapy. Drug dose: ipratropium bromide 250-500μg each time, add β2 agonist solution for nebulized inhalation, the interval is the same as the inhalation of β2 agonist.
4.Aminophylline: Intravenous aminophylline can be used as an additional treatment option for children with critical asthma. Drug dose: loading dose 4-6mg/kg (≤250mg), slow intravenous drip 20-30 min, followed by continuous drip maintenance dose 0.7-1 mg/(kg-h) according to age, if oral aminophylline has been used, directly use maintenance dose continuous intravenous drip. Can also use intermittent dosing method, every 6 to 8 hours slow intravenous drip 4 ~ 6 mg/kg.
5, magnesium sulfate: helps to relieve critical asthma symptoms, good safety. Drug dose: 25 ~ 40mg / (kg-d) (≤ 2 g / d), divided into 1 ~ 2 times, add 10% glucose solution 20ml slow intravenous infusion (more than 20min), use 1 ~ 3 d. Adverse reactions include transient flushing, nausea, etc., usually occurs when the drug infusion. If overdose can be antagonized by intravenous injection of 10% calcium gluconate.
If the condition of children with critical asthma continues to deteriorate after treatment with oxygen therapy, systemic glucocorticoids, β2 agonists, etc., adjuvant mechanical ventilation should be given promptly.
V. Treatment of clinical remission period
In order to consolidate the therapeutic effect, maintain the long-term stability of the child’s condition and improve the quality of life, the treatment of the clinical remission period should be strengthened.
1. Encourage the child to adhere to regular daily PEF measurements, monitor changes in condition, and record the asthma diary.
2. Pay attention to the presence of asthma attack aura, such as cough, shortness of breath, chest tightness, etc. Once they appear, emergency medication should be used promptly to reduce the symptoms of asthma attack.
3.Continue to use long-term control medication after remission, such as using the lowest effective maintenance amount of ICS, etc.
4.Dose adjustment and course of control therapy: for those who use medium to high dose ICS alone, try to reduce the dose by 50% after achieving and maintaining asthma control for 3 months. If control can be achieved with low-dose ICS alone, switch to once-daily dosing. For combined ICS and LABA, reduce ICS by approximately 50% until low-dose ICS is achieved before considering discontinuation of LABA, and consider discontinuation if asthma control is maintained with the lowest dose of ICS and no recurrence of symptoms for 1 year.
A significant proportion of children under 5 years of age have spontaneous remission of asthma symptoms, so the control regimen for children of this age should be evaluated at least twice a year to determine the need for continued treatment.
5. According to the specific situation of the child, including the understanding of the triggers and the pattern of previous attacks, study with the child and parents, and propose and take all necessary practical preventive measures, including avoiding exposure to allergens, preventing asthma attacks, and maintaining long-term control and stability of the disease.
6. Treatment of coexisting diseases: 70% to 80% of children with asthma also have allergic rhinitis, and some children have coexisting sinusitis and gastroesophageal reflux. These coexisting diseases can affect the control of asthma and need to be treated accordingly.
[Education and management of asthma control]
Asthma has a significant impact on the patient, the patient’s family and society. Although there is no cure for asthma, clinical control of asthma can be achieved through effective asthma education and management and the establishment of a patient-physician partnership. Asthma prevention and control education is the most essential part of achieving the goal of good asthma control.
I. Asthma prevention and control education
(A) Education content
1.The nature and pathogenesis of asthma.
2.Ways to avoid various factors that trigger and induce asthma attacks.
3.The aura of asthma exacerbation, symptom pattern and corresponding family self-treatment methods.
4.Self-monitoring, mastering the method of measuring PEF and keeping asthma diary. Apply the asthma control questionnaire to determine the level of asthma control and choose the appropriate treatment plan. Commonly used asthma control questionnaires for children are “Childhood Asthma Control Test (C-ACT)” and “Asthma Control Questionnaire (ACQ)”, etc.
5.Know the characteristics of various long-term control and rapid relief drugs, the use of drug inhalation devices (especially inhalation techniques) and the prevention and management of adverse reactions.
6.Signs of asthma attack, emergency measures and emergency indications.
7.The role of psychological factors in the development of asthma in children.
(II) Education methods
1.Outpatient education: It is the most important basic and initiation education, and it is the individualized education at the beginning of the doctor-patient partnership. Through outpatient education, patients and their family members can initially understand the basic knowledge of asthma and learn to apply inhaled drugs.
2. Centralized education: centralized and systematic education on asthma prevention and treatment through talks, exchange sessions, asthma schools (clubs), summer (winter) camps and fellowships, etc.
3. Media publicity: Promote asthma knowledge through radio, TV, newspapers, science magazines, books, etc.
4. Network education: Apply electronic network or multimedia technology to disseminate asthma prevention and control knowledge. Disseminate asthma prevention and treatment information through the China Asthma Alliance network ( www.chinaasthma.net ), Global Initiative for Asthma Prevention and Control (GINA) network ( www.ginaasthma.org ), etc. or interactive multimedia technology.
5.Specific education: cooperate with schools and community health institutions to carry out planned community, patient and public education.
6.Physician education: pay attention to the education of pediatricians at all levels. Popularize the asthma knowledge of general pediatricians, update and improve the asthma prevention and control level of specialists, and hold regular asthma learning training courses.
II. Asthma management
1.Establish partnership between doctors and patients and their families: Based on hospital specialist clinics, establish asthma homes, asthma clubs, asthma fellowships and other organizations to establish partnerships with patients and their families, so that children with asthma and their relatives have a correct and comprehensive understanding of asthma prevention and treatment and good compliance, adhere to treatment, and communicate promptly if there are problems.
2. Identify and reduce exposure to risk factors: Many risk factors can cause acute exacerbations of asthma and are called “triggers”, including allergens, viral infections, pollutants, tobacco smoke, and medications. Avoid or reduce exposure to risk factors as much as possible to prevent the onset of asthma and exacerbation of symptoms by identifying allergens through clinical allergen measurements and parental observation of daily life. Reducing the patient’s exposure to risk factors can improve asthma control and reduce the need for therapeutic drugs.
3.Establishment of asthma specialist records: establish asthma patient files, develop long-term prevention and treatment plans, and make regular (1 to 3 months) follow-up visits. The follow-up visit includes checking the asthma diary, checking whether the aspiration technique is correct, and monitoring lung function. Assess asthma control, maintain medication and guide treatment.
4. Assessment, treatment and monitoring of asthma: Asthma control is achieved and maintained through assessment, treatment and monitoring. Most patients are able to achieve this goal with a pharmacologic intervention strategy developed jointly by the physician and patient. The patient’s initial treatment is based on the severity of the patient’s asthma and the adjustment of the treatment plan is based on the patient’s level of asthma control, including a continuous cyclic process of accurate assessment of asthma control, continued treatment to achieve asthma control, and regular monitoring of asthma control.
Objective means of asthma control assessment are lung function and PEF measurements. Pulmonary function measurements can be done every 3 months if available, and patients over 5 years of age can insist on daily PEF measurements if available, and record them in an asthma diary.
Some clinically validated asthma control assessment tools such as C-ACT and ACQ can be used to assess the level of asthma control. As a supplement to lung function, both for physician and patient self-assessment of asthma control, patients can complete a self-assessment of asthma control levels before or during their visit. These questionnaires are validated methods of assessing asthma control in children and can improve two-way communication between physician and patient, providing objective indicators of continuous assessment and facilitating long-term monitoring.
During long-term asthma management treatment, objective methods of assessing asthma control are used whenever possible, with continuous monitoring to provide reproducible assessment metrics that allow for adjustment of treatment regimens, determination of the minimum level of treatment needed to maintain asthma control, maintenance of asthma control, and reduction of healthcare costs.