Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), also called chronic obstructive lung disease, is a term that is used for two closely related diseases of the respiratory system: chronic bronchitis and emphysema.

In many cases these diseases occur together, although there may be more symptoms of one than the other.

Most patients with these diseases have a long history of heavy cigarette smoking.

COPD gets gradually worse over time. At first, there may be only a mild shortness of breath and occasional coughing. Then a chronic cough develops with clear, colorless sputum.

As the disease progresses, the cough becomes more frequent and more effort is needed to get air into and out of the lungs.

In later stages of the disease, the heart may be affected. Eventually death occurs when the function of the lungs and heart is no longer adequate to deliver oxygen to the body's organs and tissues.

COPD often develops in people at the height of their productive years, disabling them with constant shortness of breath. It destroys their ability to earn a living, causes frequent use of the health care system, and disrupts the lives of the victims' family members for as long as 20 years before death occurs.

Chronic bronchitis , one of the two major disease of the lung grouped under COPD, is diagnosed when a patient has excessive airway mucus secretion leading to a persistent, productive cough. An individual is considered to have chronic bronchitis if cough and sputum are present on most days for a minimum of 3 months for at least 2 successive years or for 6 months during 1 year. In chronic bronchitis, there may also be narrowing of the large and small airways, making it more difficult to move air in and out of the lungs.

In emphysema , there is a permanent destruction of the alveoli, the tiny elastic air sacs of the lung, because of irreversible destruction of a protein in the lung called elastin that is important for maintaining the strength of the alveolar walls. The loss of elastin also causes collapse or narrowing of the smallest air passages, called bronchioles, which in turn limits airflow out of the lung.

Cigarette smoking is the most important risk factor for COPD, both in developing it to begin with and making it worse if COPD is present.

Other risk factors include age, heredity, exposure to air pollution at work and in the environment, and a history of childhood respiratory infections. Living in low socioeconomic conditions also seems to be a contributing factor.

COPD is the fifth leading cause of death in the U.S.