CHAPTER 40 Chronic Obstructive Pulmonary Disease
3 Describe chronic bronchitis and emphysema
Chronic bronchitis: Characterized by cough, sputum production, recurrent infection, and airway obstruction for many months to several years. Patients with chronic bronchitis have mucous gland hyperplasia, mucus plugging, inflammation and edema, peribronchiolar fibrosis, airway narrowing, and bronchoconstriction. Decreased airway lumina caused by mucus and inflammation increase resistance to flow of gases.
Emphysema: Characterized by progressive dyspnea and variable cough. Destruction of the elastic and collagen network of alveolar walls without resultant fibrosis leads to abnormal enlargement of air spaces. In addition, the loss of airway support leads to airway narrowing and collapse during expiration (air trapping).
4 List contributory factors associated with the development of chronic obstructive pulmonary disease
Smoking: Smoking impairs ciliary function, depresses alveolar macrophages; leads to increased mucous gland proliferation and mucus production; increases the inflammatory response in the lung; leading to increased proteolytic enzyme release; reduces surfactant integrity; and causes increased airway reactivity.
Occupational and environmental exposure: Animal dander, toluene and other chemicals, various grains, cotton, and sulfur dioxide and nitrogen dioxide in air pollution.
Recurrent infection: Bacterial, atypical organisms (mycoplasma), and viral (including human immunodeficiency virus, which can produce an emphysema-like picture).
Familial and genetic factors: A predisposition to COPD exists and is more common in men than women. α1-antitrypsin deficiency is a genetic disorder resulting in autodigestion of pulmonary tissue by proteases and should be suspected in younger patients with basilar bullae on chest x-ray film. Smoking accelerates its presentation and progression.
6 What features distinguish pink puffers from blue bloaters?
Pink puffers (emphysema) | Blue bloaters (chronic bronchitis) |
Usually older (>60 years) | Relatively young |
Pink in color | Cyanotic |
Thin | Heavier in weight |
Minimal cough | Chronic productive cough; frequent wheeze |
8 What laboratory examinations are useful?
Electrolytes: Bicarbonate levels are elevated to buffer a chronic respiratory acidosis if the patient retains carbon dioxide. Hypokalemia can occur with repeated use of β-adrenergic agonists.
Chest x-ray film: Look for lung hyperinflation, bullae or blebs, flattened diaphragm, increased retrosternal air space, atelectasis, cardiac enlargement, infiltrate, effusion, masses, or pneumothorax.
Electrocardiogram: Look for decreased amplitude, signs of right atrial (peaked P waves in leads II and V1) or ventricular enlargement (right axis deviation, R/S ratio in V6 ≤1, increased R wave in V1 and V2, right bundle-branch block), and arrhythmias. Atrial arrhythmias are common, especially multifocal atrial tachycardia and atrial fibrillation.