Managing Chronic Obstructive Pulmonary Disease [antikvár]

C h a p t e r Epidemiology and mechanisms Chronic obstructive pulmonary disease (COPD), sometimes called chronic obstructive airways disease, is a major cause of morbidity and mortality throughout the world. Despite the fact that it is increasing in prevalence, the disease has received relatively little attention from the médical profession or from the pharmaceutical industry. Recently the importance of COPD has been recognised and this has result-ed in the formulation of treatment guidelines in many countries and an investment in research. Définitions Définitions are important to characterize the différences in smoking-related diseases of the airways and to distinguish COPD from asthma. Chronic simple bronchitis is defined by a productive cough on most days for at least three months for at least two consécutive years and which cannot be attributed to other pulmonary or cardiac causes. It is a conséquence of mucus hyperplasia, resulting in hypersécrétion of mucus. Chronic simple bronchitis is not necessarily related to airway obstruction. Chronic obstructive bronchitis is due to obstruction of peripheral airways as a resuit of an inflammatory response (bronchiolitis). Emphysema is a pathological diagnosis characterized by destruction of alveolar walls, resulting in abnormal and permanent enlargement of airspaces and loss of lung elasticity, with consequent obstruction of peripheral airways. COPD is defined physiologically as chronic airflow obstruction and may be due to a mixture of emphysema and peripheral airway obstruction from chronic bronchitis. This is reflected by a réduction in maximum expiratory flow and slow forced emptying of the lungs. Extensive pulmonary damage occurs before the patient is aware of symptoms, such as exertional dyspnoea, due to the slowly progressive nature of the airflow obstruction and various coping manoeuvres. There may be a small degree of reversibility in airway obstruction (<15%), in contrast to the >15% reversibility and variability in the airflow obstruction in asthma. Chronic hypoxia occurs late in COPD and may result in pulmonary hypertension and right heart failure (cor pulmonale). Asthma differs from COPD in that there is a greater reversibility, spontaneously and with treatment with bronchodilators or with steroids (Table 1.1).