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Key Clinical Updates in Approach to Management Asthma
The guidelines of the 2019 Global Strategy for Asthma Management and Prevention Report cover (1) assessing asthma control and severity, (2) distinguishing between severe asthma and uncontrolled asthma, (3) personalized pharmacologic therapy for asthma, (4) treatment of modifiable risk factors and control of environmental factors, and (5) guided self-management education and skills training.
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ESSENTIALS OF DIAGNOSIS
Episodic or chronic symptoms of wheezing, dyspnea, or cough.
Symptoms frequently worse at night or in the early morning.
Prolonged expiration and diffuse wheezes on physical examination.
Limitation of airflow on pulmonary function testing or positive bronchoprovocation challenge.
Reversibility of airflow obstruction, either spontaneously or following bronchodilator therapy.
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GENERAL CONSIDERATIONS
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Asthma is a common disease, affecting approximately 8–10% of the population. It is slightly more common in male children (younger than 14 years) and in female adults. There is a genetic predisposition to asthma. Prevalence, hospitalizations, and fatal asthma have all increased in the United States over the past 20 years. Each year, approximately 10 million office visits, 1.8 million emergency department visits, and more than 3500 deaths in the United States are attributed to asthma. Hospitalization rates are highest among African-Americans and children, and death rates are consistently highest among African-Americans aged 15–24 years. The 2019 Global Initiative for Asthma (GINA) Report entitled Global Strategy for Asthma Management and Prevention is a comprehensive and practical resource that addresses asthma diagnosis, assessment, management and exacerbations.
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DEFINITION & PATHOGENESIS
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Asthma is a chronic disorder of the airways characterized by variable airway obstruction, airway hyperresponsiveness, and airway inflammation. No single histopathologic feature is pathognomonic but common findings include airway inflammatory cell infiltration with eosinophils, neutrophils, and lymphocytes (especially T cells); goblet cell hyperplasia, sometimes plugging of small airways with mucus; collagen deposition beneath the basement membrane; hypertrophy of bronchial smooth muscle; airway edema; mast cell activation; and denudation of airway epithelium. IgE plays a central role in the pathogenesis of allergic asthma. Interleukin-5 is important in promoting eosinophilic inflammation.
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Many clinical phenotypes of asthma have been identified. The most common is allergic asthma, which usually begins in childhood and is associated with other allergic diseases such as eczema, allergic rhinitis, or food allergy. Exposure of sensitive patients to inhaled allergens may cause symptoms immediately (immediate asthmatic response) or 4–6 hours after allergen exposure (late asthmatic response). Common allergens include house dust mites (often found in pillows, mattresses, upholstered furniture, carpets, and drapes), cockroaches, cat dander, and seasonal pollens. Substantially reducing exposure reduces pathologic findings and clinical symptoms. Nonallergic asthma is not associated with allergy. Late-onset adult asthma presents for the first time in adult life. Asthma with persistent airflow limitation is thought to be due to airway remodeling. Asthma with obesity refers to prominent respiratory symptoms in obese patients with little airway inflammation.
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Nonspecific precipitants of asthma include upper respiratory ...