Asthma is characterized by chronic airway inflammation that produces airway hyperresponsiveness to a variety of allergens and other irritants, resulting in reversible airflow limitation. Asthma is the most common chronic disease of childhood and can result in the inability of affected children to attend school normally, frequent emergency room visits, and even hospitalization. The goal of asthma control in children is to achieve good asthma control, maintain normal lung function, and try not to interfere with the child’s growth and development. Because children are growing and developing, they respond differently to medication and cooperate with the use of inhalation devices, so asthma treatment for children is different than for adults.
In standardized treatment, asthma is divided into controlling and relieving medications, and because asthma is a chronic inflammation of the airways associated with exposure to allergens, inhaled glucocorticoids (ICS) are the most effective of the controlling medications. For pediatric asthma patients of all ages, inhaled glucocorticosteroids are the first-line therapeutic agents.
Age-specific inhalation devices and dosing
Choosing the right inhalation device for the child is very important for treatment, as there are differences in coordination between children of different ages, so different devices should be chosen for inhalation therapy.
A metered-dose inhaler (MDI) with a mist storage canister (Spacer) is the most convenient and easy-to-learn way to facilitate drug deposition in the lungs while reducing the adverse effects caused by inhaled glucocorticoid deposition in the oropharynx, and is inexpensive. During acute exacerbations, a dosing inhaler can be used in conjunction with a fog storage canister, or a nebulizer device can be used to inhale the relieving drug. The nebulizer device is as efficient as a dosing inhaler with a nebulizer canister, with the disadvantage that the dose of nebulized inhalation medication is less accurate and more expensive, and the device requires regular maintenance.
Dosage and regimen of lactation hormone inhalation
Lower doses of inhaled glucocorticoids are preferred in pediatric asthma compared to adults.
Inhaled glucocorticosteroid therapy in children ≤5 years of age
In children ≤5 years of age, although there is a lack of adequate clinical studies on the dose-efficacy relationship, inhaled glucocorticoids are still considered effective in treating asthma, reducing the use of other drugs and systemic glucocorticoids (CS), and reducing the number of acute exacerbations. Its effectiveness depends on the choice of inhalation device and the ability of the child to use the device correctly. For intermittent virus-induced wheezing, the role of intermittent systemic or inhaled glucocorticoids is controversial. Continuous use of low-dose inhaled glucocorticosteroids does not prevent the early onset of transient wheezing.
Initial treatment should be low-dose inhaled glucocorticosteroid therapy for 3 months. If asthma is not controlled after 3 months of treatment with the correct inhalation technique, the best option is to double the inhaled glucocorticosteroid dose or to add a leukotriene modulator to the low-dose inhaled glucocorticosteroid. If doubling the inhaled glucocorticosteroid dose does not completely control the asthma symptoms, the treatment goals and feasibility should be discussed with the child’s family, and the child’s medication inhalation pattern and compliance should be carefully evaluated again, environmental allergen control should be enhanced, and the correct diagnosis of asthma should be evaluated again. Treatment may include further increases in inhaled glucocorticoid doses or the addition of leukotriene modifiers, theophylline, or oral glucocorticoids (OCS) for several weeks until asthma symptoms improve.
Tip: Caution should be exercised in the diagnosis of children <5 years of age The typical symptoms of asthma are paroxysmal wheezing, chest tightness and cough, but in children <5 years of age, the clinical manifestations of asthma are variable and nonspecific. In addition, cough and wheezing are common in childhood infections, so a diagnosis of asthma should be made with caution especially in children <3 years of age. In children with recurrent wheezing, if the parents have a history of asthma or eczema and have their own atopic constitution, such as a history of food allergy, allergic rhinitis and allergic dermatitis, bronchial asthma should be considered and experimental treatment or pulmonary function tests are feasible.
In children <5 years of age, the need for continued treatment needs to be evaluated periodically (every 3 to 6 months). In children with seasonal asthma, inhaled glucocorticoid therapy should be reviewed regularly after discontinuation of inhaled glucocorticoid therapy, every 3-6 weeks, and inhaled glucocorticoid therapy should be resumed if symptoms reappear.
Inhaled glucocorticosteroid therapy for children >5 years old
In children >5 years of age, the use of inhaled glucocorticoids to control asthma symptoms can reduce the number of acute asthma exacerbations and hospitalizations, and can improve lung function and airway hyperresponsiveness, thereby protecting lung function and improving quality of life. After 1 to 2 weeks of inhaled glucocorticosteroid use, most patients’ symptoms and lung function improve quickly, but better improvement of airway hyperresponsiveness requires several months of inhaled glucocorticosteroid use. However, acute asthma attacks can occur weeks to months after stopping inhaled glucocorticosteroids.
Clinical studies have shown that small doses of inhaled glucocorticoids (e.g., budesonide 100-200 μg/d) can rapidly achieve symptom control and improve lung function. In most children with mild asthma, early use of low-dose inhaled glucocorticosteroids can improve symptoms and avoid the addition of other medications. Some patients require 400 μg of budesonide daily, and only a few children require high-dose inhaled glucocorticosteroids.
Adverse effects of long-term inhaled hormones
Most parents of children with long-term inhaled glucocorticosteroid use are concerned about the safety of glucocorticosteroids. In fact, small doses of inhaled glucocorticosteroids do not cause serious adverse reactions. After the child has inhaled glucocorticosteroids using an appropriate inhalation device, the child’s response to treatment needs to be monitored. After clinical control of asthma is achieved, inhaled glucocorticosteroids should be reduced to the lowest dose necessary to maintain asthma control in order to reduce the adverse effects associated with them.
Effects on growth and development
Long-term use of high-dose inhaled glucocorticosteroids may result in slow growth and delayed puberty by about 10 years of age, but does not affect eventual adult height, and children aged 4 to 10 years are more sensitive than adolescent patients. Small doses of inhaled glucocorticoids have not been found to affect growth and development in children. In fact, uncontrolled asthma and recurrent acute attacks can also affect the development of children and their height in adulthood.
Effects on bone
Inhaled glucocorticosteroids may reduce bone deposition in male children at puberty, but there is no evidence that inhaled glucocorticosteroids increase the risk of fracture. Osteoporosis and fractures have been seen in children with high systemic glucocorticoid use. The risk of fracture is increased by 32% with 4 courses of systemic glucocorticosteroids. The appropriate use of inhaled glucocorticosteroids reduces the systemic use of glucocorticosteroids and makes the skeletal effects of hormone therapy less severe.
Effects on the hypothalamic-pituitary-adrenal axis
Changes in the hypothalamic-pituitary-adrenal axis can be detected using sensitive methods when large amounts of inhaled glucocorticosteroids are used; however, no adrenal crises associated with inhaled glucocorticosteroids have been detected in clinical trials. Adrenal crisis has occurred in children with asthma after excessive use of large amounts of inhaled glucocorticosteroids in clinical practice; therefore, inhaled glucocorticosteroid doses should be selected appropriately. No significant effects on the hypothalamic-pituitary-adrenal axis were found with inhaled budesonide <200 μg/d and equivalent doses of other inhaled glucocorticosteroids.
Effects on the central nervous system
Insomnia and hyperexcitability may be manifested with the use of inhaled glucocorticosteroids, but no CNS changes due to inhaled budesonide were observed in 2 large clinical studies with controls.
Other local adverse reactions
Local adverse reactions (thrush and hoarseness) are not a major problem with long-term use of inhaled glucocorticoids and systemic application of glucocorticoids in children. The appearance of thrush may be associated with the concomitant use of antibiotics, large and frequent inhalation of glucocorticosteroids and incorrect use of inhalation devices. Rinsing the mouth after inhaling glucocorticosteroids using a storage mist canister may reduce oral Candida infections. In addition, inhaled glucocorticosteroids did not increase the incidence of glaucoma, dental caries, or lower respiratory tract infections, including tuberculosis.
Application of hormones in acute exacerbations of asthma
Acute exacerbation
Acute exacerbation of asthma in children mainly manifests as acute or subacute onset of wheezing, dyspnea, increased cough (especially at night), decreased activity tolerance, drowsiness or reduced eating, and poor response to relieving drugs. In acute exacerbation of asthma, in addition to rapid-acting β2 agonists to dilate the bronchi as soon as possible, oxygenation and close monitoring, glucocorticoid therapy should be applied reasonably.
For children who have not used inhaled glucocorticosteroids before the exacerbation, the initial inhaled glucocorticosteroid dose is twice the recommended low-dose inhaled glucocorticosteroid, and the treatment is maintained for several weeks to months. For children already on inhaled glucocorticosteroids, doubling the dose is not certain to be effective.
Oral glucocorticosteroids are more effective early in acute exacerbations and can reduce the severity of the attack.
Recommended dose: oral prednisone 1~2 mg/(kg・d), maximum dose 20 mg/d for children <2 years old, maximum dose 30 mg/day for children 2~5 years old.
The maximum daily dose for children aged 2-5 years is 30 mg, and the efficacy can be seen 3-4 hours after administration. It should generally be used for a short period of time and can be discontinued after 3 to 5 days. Severely ill children may receive intravenous hydrocortisone succinate at 5-10 mg/kg or methylprednisolone at 1-2 mg/kg, which may be repeated at 4-8 hour intervals.
Conclusion
For children with confirmed asthma, doctors should work with the child’s family to develop a treatment plan and use glucocorticoids appropriately. Inhaled glucocorticosteroids are the first-line medication for asthma control and can improve lung function, control symptoms and reduce the number of acute exacerbations in children. Low-dose inhaled glucocorticosteroids do not cause significant systemic adverse effects. Oral glucocorticosteroids should be considered only for acute exacerbations of asthma. During maintenance inhaled glucocorticosteroid therapy for asthma, physicians should periodically evaluate the treatment regimen and associated adverse effects in order to ensure the effectiveness and safety of treatment.