Bronchial asthma is a chronic inflammatory disease of the airways involving a variety of 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, biological and other irritants, to widespread and variable reversible airflow limitation, resulting in recurrent episodes of wheezing, coughing, shortness of breath, chest tightness, etc., often occurring or worsening at night and/or early in the morning, with most children in treatment remission or self-remission.
Bronchial asthma is the most common chronic disease in childhood, and the prevalence of childhood asthma in China has been increasing significantly in the past decade or so, which seriously affects the physical and mental health of children, and also brings heavy mental and economic burdens to families and society.
Children are in the process of growth and development, and the clinical phenotype of asthma varies among children of all ages due to the different anatomical, physiological, fatigue-free and pathological characteristics of the respiratory system. The diagnosis and treatment methods of asthma are also different due to the different response to medication and the degree of coordination and cooperation, etc.
I. Diagnostic criteria for bronchial asthma
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. Disseminated or diffuse croup, mainly in the expiratory phase, 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 one of the following should be present: (1) positive bronchial excitation test or exercise excitation test; (2) confirm the presence of reversible airflow limitation: (1) positive bronchodilator test: 15 min after inhalation of rapid-acting β2 agonist [such as salbutamol (SalbutamoI)] first second expiratory volume (FEV1) Increase ≥ 12% or ② Effective anti-asthma treatment: Increase in FEVl ≥ 12% after 1 to 2 weeks of treatment with bronchodilators and oral (or inhaled) glucocorticoids; (3) Maximum expiratory flow (PEF) daily variability (continuous monitoring for 1-2 weeks) ≥ 20%.
Those who meet Articles l to 4 or 4 and 5 can be diagnosed as asthma.
Second, the 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 disappear 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 and no 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) Late-onset 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 children with 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, pulmonary impairment often starts in preschool, so it is necessary to identify children with wheezing who may develop persistent asthma from 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 indicated in wheezing children with 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 viral infection; (4) wheezing symptoms persisting beyond 3 years of age.
Asthma prediction 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 were considered positive for asthma prediction index and recommended to be treated according to asthma specifications.
Primary risk factors include (1) parental history of asthma, (2) diagnosis of atopic dermatitis by a physician, and (3) basis for sensitization to inhaled allergens.
Secondary risk factors include (1) evidence of food allergen sensitization, (2) peripheral blood eosinophils ≥4%, and (3) wheezing unrelated to the flu.
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 (3-6 months) to determine the need for continued antiasthmatic therapy.
III. Diagnostic criteria for cough variant asthma
Cough variant asthma 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 attacked or aggravated at night and/or early in the morning, with a predominantly dry cough; (2) no clinical signs of infection or ineffective after prolonged antibiotic treatment; (3) effective diagnostic treatment with anti-asthmatic drugs; (4) exclusion of other causes of chronic cough; (5) positive bronchial excitation test and/or PEF daily variability rate (continuous monitoring for 1 to 2 weeks) ≥20%; (6) positive bronchial excitation test and/or PEF daily variability rate (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 items 1 to 4 are the basic conditions for diagnosis.
– From the Guidelines for the Diagnosis and Prevention of Bronchial Asthma in Children, revised by the Respiratory Group of the Pediatrics Branch of the Chinese Medical Association and the Editorial Committee of the Chinese Journal of Pediatrics in 2008
IV. What are the principles and goals of treating asthma?
(A) Principles of treatment
(1) Try to find the cause and/or trigger and avoid it.
(2) Concurrent antispasmodic and anti-inflammatory treatment (i.e., treating both the symptoms and the root cause).
3) Insist on long-term regular treatment during remission.
(4) Individualize the treatment drugs.
5）Actively promote the popularization of inhalation therapy.
6）Strengthen self-management education and disease monitoring.
(II) Treatment goals
At present, with the understanding of asthma, the aim of treating asthma is no longer satisfied with relieving wheezing, but to fundamentally clear the allergic inflammation of airways, improve the quality of survival of patients, ensure normal growth and development, and make them live like normal people. Therefore, successful treatment should achieve the following goals.
(1) To control asthma symptoms as soon as possible to the minimum or even no symptoms at all, including no symptoms at night.
(2) Minimize the number of asthma attacks or even no attacks.
(3) Minimize or even eliminate the use of β2 agonists and other asthma control medications.
(4) Minimize the number of side effects of the drugs used, preferably none.
(5) Avoid complications.
(6) Activities are not restricted, growth and development are normal, and study, work and live like normal people.