COPD is characterized by airflow limitation that is poorly reversible. Cumulative, chronic exposure to cigarette smoking is the number one cause of the disease, but repeated exposure to secondhand smoke, air pollution and occupational exposure (to coal, cotton, grain) are also important risk factors.
Chronic inflammation plays a major role in COPD pathophysiology. Smoking and other airway irritants cause neutrophils, T-lymphocytes, and other inflammatory cells to accumulate in the airways. Once activated, they trigger an inflammatory response in which an influx of molecules, known as inflammatory mediators, navigate to the site in an attempt to destroy and remove inhaled foreign debris.
Under normal circumstances, the inflammatory response is useful and leads to healing. In fact, without it, the body would never recover from injury. In COPD, repeated exposure to airway irritants perpetuates an ongoing inflammatory response that never seems to shut itself off. Over time, this process causes structural and physiological lung changes that get progressively worse.
As inflammation continues, the airways constrict, becoming excessively narrow and swollen. This leads to excess mucus production and poorly functioning cilia, a combination that makes airway clearance especially difficult. When people with COPD can't clear their secretions, they develop the hallmark symptoms of COPD, including a chronic, productive cough, wheezing and dyspnea. Finally, the build-up of mucus attracts a host of bacteria that thrive and multiply in the warm, moist environment of the airway and lungs. The end result is further inflammation, the formation of diverticula (pouch-like sacs) in the bronchial tree, and bacterial lung infection, a common cause of COPD exacerbation.
COPD is the third-leading cause of death in the United States, preceded by only heart disease and cancer. It kills over 126,000 Americans annually. Historically, COPD has occurred more frequently in men; however, since 2000, more women have died each year from the disease than men. To date, COPD remains a growing healthcare concern for women in many countries. See COPD in Women.
COPD predominantly occurs in people over 40 years of age. According to the Centers for Disease Control and Prevention, 15 million Americans have been diagnosed with COPD as of 2011. However, approximately 24 million U.S. adults have evidence of impaired lung function, indicating that there is a high probability of under-diagnosis
To make an accurate diagnosis of chronic obstructive pulmonary disease, a complete history and physical assessment must be taken that should start with a thorough review of your family history, as well as your history of exposure to tobacco smoke and other types of environmental and/or occupational exposures. Additional diagnostic tests may include: Blood tests (including arterial blood gases and a complete blood count, particularly hemoglobin and hematocrit levels) Chest X-ray
Pulmonary function tests
Routine lab tests are often done on individuals who have been diagnosed with COPD. These tests include what is known as the Complete Blood Count (CBC) and a basic chemistry profile. Other tests that are ordered for individuals with lung diseases are discussed below.
Arterial Blood Gases
An arterial blood gases (ABGs) test may be ordered to give your doctor more information about your lung health. ABGs determine how well your lungs are getting oxygen into your blood and carbon dioxide out of your blood. A sample of blood is drawn from an artery, most often near the wrist.
The needle stick usually hurts a bit but the information obtained can be very important. The most important measurements in the blood gas sample are the acid/base balance (pH), the carbon dioxide level (PaCO2), the oxygen level (PaO2) and oxygen...
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