Chronic Obstructive Pulmonary Disease (COPD), a common preventable and treatable disease, is characterized by airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways and the lung to noxious particles or gases. Exacerbations and comorbidities contribute to the overall severity in individual patients.
COPD subtypes includes; emphysema, chronic bronchitis, and chronic obstructive asthma.
— Chronic bronchitis: Chronic bronchitis is defined as a chronic productive cough for three months in each of two successive years in a patient in whom other causes of chronic cough (eg, bronchiectasis) have been excluded.
— Emphysema: Emphysema is defined by abnormal and permanent enlargement of the airspaces distal to the terminal bronchioles that is accompanied by destruction of the airspace walls, without obvious fibrosis (ie, there is no fibrosis visible to the naked eye). Exclusion of obvious fibrosis was intended to distinguish the alveolar destruction due to emphysema from that due to the interstitial pneumonias. However, many studies have found increased collagen in the lungs of patients with mild COPD, indicating that fibrosis can be a component of emphysema. While emphysema can exist in individuals who do not have airflow obstruction, it is more common among patients who have moderate or severe airflow obstruction. The various sub-types of emphysema includes; proximal acinar, panacinar, distal acinar.
— Asthma: The Global Initiative for Asthma gives the following definition of asthma: “Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. The chronic inflammation is associated with airway responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning. These episodes are usually associated with widespread, but variable, airflow obstruction within the lung that is often reversible either spontaneously or with treatment.