Chronic obstructive pulmonary disease

What it is

COPD includes chronic bronchitis and emphysema, and most patients are along an overlap spectrum of the two.

• Chronic bronchitis is a clinical diagnosis: chronic cough and sputum production for at least 3 months a year for two consecutive years, if other causes of chronic cough are excluded.
• Emphysema is a pathological diagnosis: abnormal and permanent enlargement of the airspaces distal to the terminal bronchioles with destruction of airspace walls.

Emphysema has two subtypes. Centrilobular (centriacinar) is the most common, classically seen in smokers: destruction of the respiratory bronchiole, the central portion of the acinus, which spares distal alveoli, usually in the upper lobes - smoke rises up. Panlobular (panacinar) is rare and associated with alpha-1-antitrypsin deficiency: destruction of the entire acinus, usually the lower lobes. Set out as a definition: COPD is a heterogeneous lung condition characterized by chronic respiratory symptoms, that is dyspnea, cough, sputum production and exacerbations, due to abnormalities of the airways, bronchitis and bronchiolitis, and of the alveoli, emphysema, that cause persistent, often progressive, airflow obstruction. The picture under that is bronchioles that lose their shape and become clogged, and walls of alveoli that are destroyed, forming fewer larger alveoli.