Introduction
Asthma Pediatric_Disease Background 1
Asthma is a heterogeneous disease with chronic inflammatory disorder of the airways. This is the most common chronic disease in pediatric age groups that causes significant morbidity.
Epidemiology
According to the World Health Organization (WHO), asthma is a major noncommunicable disease affecting approximately 262 million people worldwide. According to the Global Burden of Disease report, asthma is responsible for approximately 420,000 deaths annually worldwide. Studies show that asthma prevalence varies considerably between countries, and prevalence is highest among Black individuals and lowest among Asian and Hispanic individuals. Asthma is more prevalent in males than females and increases with age, from 4% in ages 0–4 to 10.5% in ages 12–17.
Pathophysiology
Asthma Pediatric_Disease Background 2
Asthma is characterized by chronic airway inflammation, intermittent airflow obstruction, and bronchial hyperresponsiveness caused by interactions among inflammatory and airway cells. Mast cell and eosinophil mediators, such as histamine and leukotrienes, promote bronchoconstriction. Airflow obstruction results from airway smooth muscle contraction, airway wall edema, mucus plugging, and airway remodeling. In severe or early-onset asthma, airway remodeling can cause irreversible airway changes and accelerated decline in lung function.
Risk Factors
Risk factors for asthma include family history of asthma, atopic disease (eg atopic dermatitis, allergic rhinitis), maternal smoking, premature birth or low birth weight, and obesity. Asthma exacerbations may be triggered by airborne irritants (eg air pollution, chemicals), aeroallergens (eg pollen, mold dusts), respiratory infections (eg rhinovirus, respiratory syncytial virus [RSV]), drugs (eg Aspirin, NSAIDs), psychological stress, temperature changes and exercise.