What causes chronic obstructive pulmonary disease (COPD)?
Chronic obstructive pulmonary disease is caused by exposure to noxious gases or particles, especially cigarette smoke. Over time, this exposure damages the airways. The airways try to protect themselves by making more mucus. However, the lungs may slowly get damaged from chronic irritation. The increased mucus and lung damage can be permanent.
Cigarette smoking is the most important cause of COPD, although only about 15 to 20% of smokers develop the disease. Pipe and cigar smokers develop COPD more often than nonsmokers but not as often as cigarette smokers. With age, susceptible cigarette smokers lose lung function more rapidly than nonsmokers. If a person stops smoking, there is little improvement in lung function. However, the rate of decline of lung function does return to that of nonsmokers when the person stops smoking, thus delaying the progression of symptoms.
Frequent exposure to air pollution and industrial fumes and dusts, as well as frequent bacterial infections of the upper respiratory system can also cause COPD. With chronic bronchitis, the airways become irritated by smoke or other pollutants in the air, then swell and produce a large amount of mucus. The swelling and irritation can scar the walls of the bronchial airways and cause the smooth muscles in the airways to spasm, which stimulates coughing. The mucus clogs the airways and makes it difficult to breathe. In normal lungs, tiny air sacs called alveoli support the small airways, called the bronchioles, and hold the airways open. With emphysema, smoke causes an overproduction of an enzyme that destroys the walls of the alveoli, so the bronchioles no longer have any support. When the bronchioles collapse, the airway becomes permanently narrowed.
Other lung irritants that are inhaled over a long period of time - such as industrial dust and chemical fumes - may also contribute to COPD.
Some people may be more susceptible to developing COPD than others; this is also likely because of genetic factors. Your chances of developing COPD may be increased if a close relative also had COPD. A low birth weight and repeated lung infections may also make a person more susceptible to COPD. A rare cause of COPD is a hereditary condition in which the body produces a markedly decreased amount of the protein alpha1-antitrypsin. Some families have an inherited form of emphysema called "early onset emphysema" because it can appear as early as 30 to 40 years of age. This type of emphysema is caused by low levels of an enzyme inhibitor called alpha-1-antitrypsin (AAT).
More information on chronic obstructive pulmonary disease (COPD)
What is chronic obstructive pulmonary disease (COPD)? - Chronic obstructive pulmonary disease (COPD) is persistent obstruction of the airways occurring with emphysema, chronic bronchitis, or both disorders.
What causes chronic obstructive pulmonary disease (COPD)? - Chronic obstructive pulmonary disease is caused by exposure to noxious gases or particles, especially cigarette smoke.
What're the risk factors for chronic obstructive pulmonary disease? - The leading risk factor for COPD is smoking, which can lead to the two most common forms of this disease, emphysema and chronic bronchitis.
What're the symptoms of chronic obstructive pulmonary disease? - People who have chronic obstructive pulmonary disease (COPD) usually have some symptoms of both chronic bronchitis and emphysema.
How is chronic obstructive pulmonary disease (COPD) diagnosed? - Diagnosis of COPD begins with a medical history and physical examination. Other diagnostic tests for COPD include an arterial blood gas.
What's the treatment for hronic obstructive pulmonary disease (COPD)? - The goals of COPD treatment are to prevent further deterioration in lung function, to alleviate symptoms, and to improve performance of daily activities.
How to prevent hronic obstructive pulmonary disease (COPD)? - Lifestyle modifications that can help prevent COPD, or improve function in COPD patients, include: quitting smoking, avoiding respiratory irritants.