Pathophysiology of COPD

Chronic obstructive pulmonary disease (COPD) encompasses a group of lung conditions that cause narrowing of the airways, leading to the shortness of breath and difficulty in breathing. It is a progressive disease in which symptoms worsen with time. Chronic bronchitis and emphysema are the most common forms of COPD. In chronic bronchitis, the lining of the airways is thickened as a result of constant irritation, which leads to an excess secretion of mucous. In case of emphysema, the elasticity of mucous lining is reduced, resulting in the obstruction of airflow.

Majority of the cases of chronic obstructive pulmonary disease are caused due to long-term smoking. Inhalation of lung irritants such as pollens, air pollutants, dust, smoke and other chemicals may also contribute to developing COPD. The early signs of COPD are chronic cough and coughing up mucous secretions. Other symptoms of COPD may include breathing difficulty, chest tightness or discomfort, wheezing and other respiratory symptoms. A patient with COPD is more susceptible to constant chest infections than a healthy person. COPD is one of the leading causes of illness and death in many countries.

Pathophysiology of COPD

The pathophysiology of COPD is very complex and is not clearly identified as yet. A resistance to the airflow can be attributed to many factors such as mucociliary disorders, inflammatory responses and structural changes. In short, the blockage and/or narrowing of the airways may be caused due to loss of elasticity of the airways, damage or inflammation in the walls of the airways, secretion of excess mucous in the airways and decrease in the surface area for the exchange of air. According to medical studies, it is revealed that chronic inflammatory responses of the airways is the major contributing factor to the development of COPD. It is stated that inflammatory responses resulted from COPD and those from asthma are different.

COPD associated inflammation induces the production of neutrophils, macrophages and lymphocytes. These cells along with reactive oxygen and proteases enzymes are responsible for causing damage to the airways (alveoli). When smoking, the number of neutrophils is increased than the normal level. Gradually, the airways are thickened, excess smooth muscles and connective tissues are produced by the body, leading to fibrosis in the airways. All these inflammatory responses are caused due to prolonged cigarette smoking and at times, frequent exposure to lung irritants.

The pathophysiology of COPD thus includes the narrowing of the airways, damage to the lungs and other supportive tissues, hyperactivity of the lungs, dysfunction of the cilia in the airways and constant damage of the alveolar walls. As the COPD condition progresses, patients of COPD manifest wheezing, productive cough, difficulty in clearing alveoli and shortness of breath (dyspnea). As the pressure in the chest increases, the patient faces more difficulty during exhaling air, rather than inhalation.

There is no cure for COPD, as damage in the airways cannot be reversed back. However, there are certain treatment options in order to manage the breathlessness symptoms. The effective treatment of COPD is to quit smoking; one can opt for nicotine replacement therapy to cope up the withdrawal symptoms. Other treatment options of COPD include oxygen therapy (if necessary) and medications such as corticosteroids and antibiotics (for chest infection).