Key Points
- Asthma is a chronic inflammatory airway disease characterized by reversible airflow obstruction and bronchial hyperresponsiveness.
- Acute exacerbations require prompt bronchodilation and anti-inflammatory therapy to restore airway patency.
- Long-term control involves inhaled corticosteroids, bronchodilators, and trigger avoidance.
- Patient education, adherence, and psychosocial support are essential to reduce morbidity and improve quality of life.
Introduction
Asthma affects over 300 million individuals worldwide. It manifests as episodic wheezing, breathlessness, chest tightness, and coughing. Effective management requires both pharmacologic treatment and comprehensive patient-centered strategies.
Epidemiology and Risk Factors
- Global Burden: Prevalence varies by region, affecting 5–10% of adults and up to 15% of children.
- Risk Factors:
- Genetic predisposition (family history of atopy).
- Environmental exposures (allergens, air pollution, tobacco smoke).
- Early-life respiratory infections and obesity.
Pathophysiology
Asthma involves chronic airway inflammation mediated by:
- Immune Cell Activation: Eosinophils, mast cells, and T lymphocytes release cytokines and mediators.
- Bronchial Hyperresponsiveness: Increased sensitivity to stimuli leading to airway narrowing.
- Airway Remodeling: Chronic inflammation causes structural changes, including subepithelial fibrosis and smooth muscle hypertrophy.
Clinical Manifestations
- Symptoms: Intermittent wheezing, dyspnea, chest tightness, and cough (often nocturnal or early morning).
- Exacerbations: Sudden worsening requiring urgent treatment; triggers include infections, allergens, and irritants.
Diagnosis
- Spirometry: Demonstrates reversible airflow obstruction (FEV₁ increase ≥12% and 200 mL post-bronchodilator).
- Peak Flow Monitoring: Tracks variability in daily measurements.
- Bronchoprovocation Testing: Identifies airway hyperresponsiveness (methacholine challenge).
- Allergy Testing: Skin or serum tests to identify sensitizing allergens.
Management
Acute Exacerbation
- Inhaled Short-Acting Beta2-Agonists (SABA):
- Albuterol or levalbuterol via metered-dose inhaler or nebulizer.
- Systemic Corticosteroids:
- Oral or intravenous prednisone/methylprednisolone to reduce airway inflammation.
- Oxygen Therapy:
- Maintain SpO₂ ≥92%.
- Adjunctive Agents (if needed):
- Ipratropium bromide (inhaled anticholinergic).
- Magnesium sulfate IV for severe refractory cases.
Long-Term Control
| Step | Controller Medications | Preferred Reliever |
|——|————————————————-|————————-|
| 1 | As-needed low-dose ICS-formoterol (preferred) | ICS-formoterol |
| 2 | Daily low-dose inhaled corticosteroids (ICS) | SABA or ICS-formoterol |
| 3 | Low-dose ICS + LABA or medium-dose ICS | SABA |
| 4 | Medium/high-dose ICS + LABA | SABA |
| 5 | High-dose ICS + LABA + add-on (e.g., tiotropium)| SABA |
| 6 | Consider biologics (anti-IgE, anti-IL5) | SABA |
- Inhaled Corticosteroids (ICS): Mainstay for reducing airway inflammation.
- Long-Acting Beta2-Agonists (LABA): Add-on for persistent symptoms.
- Leukotriene Receptor Antagonists: Montelukast for mild allergic asthma.
- Biologic Therapies: Omalizumab, mepolizumab for severe eosinophilic asthma.
Trigger Avoidance and Environmental Control
- Identify and reduce exposure to allergens (dust mites, pet dander, molds).
- Smoking cessation for patients and household members.
- Air quality management (avoid outdoor exercise during high pollution).
Patient Education and Self-Management
- Asthma Action Plan: Personalized plan for daily management and exacerbation steps.
- Inhaler Technique: Regular assessment to ensure proper medication delivery.
- Adherence: Emphasize consistency in controller therapy even when asymptomatic.
- Monitoring: Self-monitor peak flow and symptom diary to detect early exacerbations.
Psychological and Behavioral Interventions
- Address anxiety or depression that may worsen asthma control.
- Relaxation techniques and breathing exercises (e.g., diaphragmatic breathing).
- Biofeedback and stress-management strategies, particularly in pediatric patients, to improve symptom perception and reduce attacks.
References
- Global Initiative for Asthma (GINA) Report 2025.
- National Asthma Education and Prevention Program Expert Panel Report 2020.
- Reddel HK, et al. A summary of the key changes in asthma management. Eur Respir J. 2023.
- Pavord ID, et al. Clinical Characterization and Targets for Biologic Therapy in Asthma. Chest. 2022.