Chronic obstructive pulmonary disease, also known as COPD, is a group of lung conditions that impede airflow and make breathing very difficult. The two most common conditions that make up chronic obstructive pulmonary disease are chronic bronchitis and emphysema. Bronchitis occurs when the bronchial tubes, which carry air to and from the lungs, become inflamed. Bronchitis is fairly common, and someone who gets bronchitis does not necessarily have chronic obstructive pulmonary disease. A condition like bronchitis is typically not considered chronic until it persists for six months or longer. Emphysema is the result of air sacs in the lungs called alveoli being progressively destroyed. The alveoli destroyed in emphysema are located at the ends of the smallest air passages in the lungs known as bronchioles. Damage to the lungs as a result of chronic obstructive pulmonary disease cannot be reversed. However, treatment may help minimize symptoms and prevent further severe damage.
The most common cause of chronic obstructive pulmonary disease is tobacco smoking. Chronic obstructive pulmonary disease affects the lungs by causing bronchial tubes and air sacs in the lungs to lose their elasticity and partially collapse. Every time someone inhales, the air goes down the trachea (windpipe), through the bronchi, and into the lungs. In the lungs, the bronchi break off into much smaller tubes called bronchioles that end in clusters of alveoli, which are air sacs. The walls of the alveoli are lined with capillaries, which are very small blood vessels. Oxygen from the alveoli enters the bloodstream through these capillaries, and, simultaneously, carbon dioxide is exhaled. The bronchial tubes and alveoli have a natural elasticity that is needed to force inhaled air back out of the body. Therefore, as chronic obstructive pulmonary disease causes the bronchial tubes and air sacs to lose their elasticity, some air stays trapped in the lungs and cannot be completely exhaled.
Emphysema and chronic bronchitis are the two specific causes of airway obstruction in chronic obstructive pulmonary disease. Emphysema destroys the walls and fibers of the alveoli. Small airways collapse during exhalation, impeding airflow out of the lungs. Chronic bronchitis causes the bronchial tubes to become inflamed and narrowed. The lungs also produce more mucus, further blocking the narrowed bronchial tubes. A chronic cough develops in an attempt to clear the airways. As stated previously, the most common irritant that causes chronic obstructive pulmonary disease is long-term exposure to cigarette smoke, but air pollution, and exposure to dust, smoke, or fumes can also cause chronic obstructive pulmonary disease.
Signs and symptoms of chronic obstructive pulmonary disease include shortness of breath particularly during physical activity, wheezing, a feeling of chest tightness, persistent cough that produces clear, white, yellow, or greenish phlegm, blueness of the lips or fingernail beds (cyanosis), frequent respiratory infections, and decreased energy. Other effects on the body due to chronic obstructive pulmonary disease known as complications are a higher susceptibility to respiratory infections like influenza and pneumonia, high blood pressure, increased risk of heart disease and heart attack, higher risk for lung cancer, and depression. Chronic obstructive pulmonary disease is characterized by exacerbations, which is the sudden worsening of symptoms for days or weeks despite treatment. These exacerbations may lead to lung failure if prompt medical treatment is not received. Chronic obstructive pulmonary disease is a manageable condition, with smoking cessation being the most important factor in preventing the progression of the disease.
Reference
Mayo Clinic. (2013). COPD. Retrieved from http://www.mayoclinic.com/health/copd/DS00916.
