Obstructive lung diseases constitute a clinical domain defined by increased airway resistance that predominantly impairs expiratory airflow rather than inspiration. The core pathophysiological mechanism involves structural and functional alterations, such as reversible bronchoconstriction in asthma or permanent destruction of alveolar walls in emphysema, leading to reduced gas exchange efficiency. These conditions are categorized into specific theoretical types including Asthma (atopic/non-atopic), Chronic Bronchitis, Emphysema, and Bronchiectasis, each with distinct etiological profiles ranging from immune-mediated hypersensitivity reactions to genetic defects like alpha-1 antitrypsin deficiency or cystic fibrosis.
Asthma is an obstructive lung disease of the small airways driven by immunologic inflammation, bronchospasm, mucus production, and airway edema, producing a classically reversible obstructive pattern…