A 74-year-old woman and longtime smoker presents with fatigue and shortness of breath. She has not seen a physician for many years and says she has been basically healthy. On physical examination, she is found to be pale, mildly cachectic, and her lips are cyanotic. Her breath sounds are distant, although crackles can be heard in both lung bases. Her heart sounds are best heard in the epigastrium; a third heart sound is present. She has mild peripheral edema. Her resting pulse oximetry is 74%. Her chest X-ray (CXR) shows emphysema (Figure 56-1) and her echocardiogram confirms heart failure.
Emphysema with mild hyperinflation and increased interstitial markings. (From Miller WT Jr. Diagnostic Thoracic Imaging. New York: McGraw-Hill; 2006:106, Figure 3-37 A. Copyright 2006.)
Chronic obstructive pulmonary disease (COPD) is defined as a disease state characterized by airflow limitation that is usually progressive and associated with an abnormal inflammatory response of the lung to noxious particles or gases.1 COPD is preventable and treatable. Some patients have significant extrapulmonary effects (particularly cardiac) that may contribute to disease severity. Worldwide, tobacco smoke is the primary cause of COPD (Figure 56-2).
Gross pathology of lung showing centrilobular emphysema caused by tobacco smoking. Close-up of cut surface shows multiple cavities lined by heavy black carbon deposits. (Courtesy of Centers for Disease Control and Prevention [CDC] and Dr. Edwin P. Ewing, Jr.)
Emphysema (technically refers to destruction of the alveoli).
- Estimated prevalence of COPD in adults older than age 18 years in the United States (2008) is about 13.2 million cases, or 4% of the population (95% confidence interval [CI], 3.8 to 4.1).2
- Fourth leading cause of death both in United States and worldwide. Mortality rates have declined for men from 1999 to 2006 (57 per 100,000 to 46.4 per 100,000) and remained fairly stable for women (35.3 per 100,000 to 34.2 per 100,000).3
- In a study in Latin America, prevalence rates ranged from 7.8% to 19.7% of the population;4 a prevalence of between 3% and 11% has been reported in never-smokers.1 This high rate among never-smokers is most likely related to indoor cooking with open wood fires.
- In a Swedish study of COPD (birth cohorts from 1919 to 1950), the 10-year cumulative incidence rate of COPD was 13.5% using Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria (Table 56-1) based on 1109 patients with baseline respiratory symptoms (76.6% of the original symptomatic cohort and 16.7% of the total cohort).5
- Estimated direct costs associated with COPD in the United States are more than $29 billion with additional indirect costs of $20.4 billion.1
Table 56-1 COPD Severity—GOLD Grade