Chronic obstructive pulmonary disease (COPD) is a progressive disease that includes emphysema and chronic bronchitis. Asthma and alpha-1 related emphysema are also categorized under the term COPD under certain circumstances. Symptoms include frequent coughing, increased sputum production, shortness of breath and wheezing. As an obstructive disease, COPD makes it difficult to exhale or breathe out entirely. According to the U.S. Centers for Disease Control and Prevention, it is the nation's fourth leading cause of death. Learning more about COPD is the first step in developing a treatment plan to improve the quality of life and life expectancy.
Emphysema
Emphysema involves the alveoli or air sacs in the lungs. A healthy lung has more than 300 million balloon-like alveoli. Like a balloon, it takes a bit of work to blow it up, but no effort at all to release the air. In the case of emphysema, the disease degrades the air sacs, destroying the elasticity; air can get in, but it becomes more and more difficult to squeeze the air out. As the disease progresses, the sacs retain more and more air causing an abnormal hyperinflation or air trapping in the bronchial tubes as well as the air sacs. As you try to breathe, a feeling of shortness of breath occurs. The obstruction component occurs as breathing becomes less efficient and more difficult.
Chronic Bronchitis
Bronchitis is inflammation of the bronchi or bronchioles causing an increase in mucus production leading to increased coughing, inflammation and swelling of the airway. The airway becomes narrower preventing air from reaching the alveoli. Chronic bronchitis is coughing with increased mucus production for the majority of time during a three-month period, for two consecutive years. Chronic bronchitis and emphysema are COPD.
Asthma
Asthma also causes inflammation and swelling of the airways, increased mucus production, and narrowing of the airway as allergens such as pollen, mold, dust and pet dander can irritate the airway causing an allergic reaction. This reaction is similar to the obstructive component of chronic bronchitis. In this case, asthma only compounds the disease state of individuals already suffering from COPD.
Alpha-1 Related Emphysema
Alpha-1 (AAT) related emphysema can also be a component of COPD. AAT is an inherited disease that characterized by a missing protein that produced in the liver, called alpha-1 antitrypsin. Everyone inherits one AAT gene from each parent. A deficiency occurs when you inherit two abnormal genes. Normally, AAT traps and destroys the neutrophil elastase, the enzyme that digests damaged and aging cells and bacteria in the lungs. Without AAT, the enzyme goes beyond the digestion phase and attacks lung tissue resulting in alpha-1 related emphysema.
Chronic Hypoxemia
As the result of worsening emphysema and bronchitis, the PaC02 or carbon dioxide levels in the COPD patient will gradually increase over time due to air trapping in the lungs. Since air trapping and carbon dioxide retention are gradual, the body slowly adapts to an increasingly higher C02 level. At some point in the disease process, however, the C02 chemoreceptor (the body's way of sensing carbon dioxide and telling us to breathe, to exhale it, and breathe in fresh air or oxygen) will cease to respond to carbon dioxide as a stimulus for breathing.
