Pulmonary Diseases Attributed to Aerosol Therapy

Bronchial asthma is characterized by an increased responsiveness of the trachea and bronchi to various stimuli and is manifested by a widespread narrowing of the airways that changes in severity either spontaneously or as a result of therapy (91). Chronic bronchitis is defined as a condition with chronic or recurrent bronchial hypersecretion, cough and expectoration during at least 3 months for at least 2 successive years (92). Chronic bronchitis is often associated with chronic airways obstruction with minimal reversibility it is then called chronic obstructive pulmonary disease (COPD). Chronic airways obstruction in COPD is believed to be caused by either emphysema or irreversible obstructive changes in the peripheral airways, or both. There is an overlap between asthma and COPD, and many patients may have features of both diseases (93). Asthma is considered an important risk factor for the development of COPD. Bronchial hyperresponsiveness is a hallmark of asthma, whereas its importance in COPD is more obscure. Airway inflammation is a key factor for the development of bronchial hyperresponsiveness (94). Table 4 shows the main pathophysiological features of airways obstruction in asthma, chronic bronchitis, and emphysema. 

Bronchial hyperresponsiveness Mucus hypersecretion Loss of alveolar walls 

Airway inflammation (eosino-philia) Mucous gland hypertrophy Bronchiolitis 

Smooth-musele hypertrophy Mueosal edema Hyperseeretion or plugging Epithelial sloughing Normal or impaired clearanee Mural thickening Loss of cilia Impaired clearance Normal clearance 

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