copd.pdf

1 Disease Profiles Chronic Obstructive Pulmonary Disease (COPD) DEFINITION A set of respiratory disorders that present with increasing resistance to airflow. The major obstructive lung diseases are chronic...

1 Disease Profiles Chronic Obstructive Pulmonary Disease (COPD) DEFINITION A set of respiratory disorders that present with increasing resistance to airflow. The major obstructive lung diseases are chronic bronchitis, emphysema, and asthma (see information on Asthma review card).  Emphysema (type A COPD) is denoted by abnormal, permanent enlargement of air spaces distal to the terminal bronchioles with destruction of their walls and without obvious fibrosis.  Chronic bronchitis (type B COPD) is characterized by excessive secretion of bronchial mucus and is manifested by productive cough for 3 months or more in at least 2 consecutive years in the absence of any other disease process that may cause this symptom. ETIOLOGY  Emphysema: Causes are not fully understood. It is associated with cigarette smoking; air pollution; and certain occupations, such as welding, mining, and working with asbestos.  Chronic bronchitis: Major causes are cigarette smoking, repeated viral or bacterial infections, genetic predisposition, and inhalation of physical or chemical irritants. PATHOGENESIS  Emphysema: Alveolar destruction is caused by release of inflammatory proteolytic enzymes that degrade lung proteins, which results in decreased surface area for gas exchange and airway collapse from loss of radial traction.  Chronic bronchitis: Associated with persistently narrowed airways because of chronic inflammation, scarring, and excessive mucus production; airway obstruction leads to poor ventilation of alveoli and impaired exchange of oxygen and carbon dioxide. CLINICAL MANIFESTATIONS  Diagnosis is based on the history, physical findings, chest radiographs, arterial blood gas analyses, echocardiogram, and pulmonary function tests (PFTs); classic PFT findings include decreased FEV1, a low FEV1/forced vital capacity ratio, increased residual volume, and increased functional residual capacity.  Emphysema: Characterized by dyspnea, weight loss, use of accessory muscles to breathe, a flat diaphragm, and a barrel chest; cyanosis is a late sign.  Chronic bronchitis: Patient is typically overweight, has dyspnea and chronic cough with excessive sputum; late signs of disease include cyanosis, edema, and signs of cor pulmonale. TREATMENT IMPLICATIONS  Because emphysema and chronic bronchitis are commonly seen in combination, therapy is given for the combined disorder and includes removal of the etiologic factor (e.g., cigarette smoke), bronchodilator therapy, bronchial hygiene to mobilize secretions, graded aerobic exercise, respiratory rehabilitation, proper nutrition, and low-dose supplemental oxygen