By John Messmer
Penn State Family & Community Medicine
Penn State Milton S. Hershey Medical Center
Penn State College of Medicine
It's the fourth leading cause of death in the United States and many people haven't even heard of it. About 24 million Americans have been diagnosed with some form of Chronic Obstructive Pulmonary Disease (COPD) and about 120,000 or 43 out of every 100,000 people die from it annually. In 2000, more women than men were hospitalized for it and had more deaths from it than men for the first time.
What is it? As the name indicates, it is a long-term lung disease which blocks air movement. There are three classifications, depending on the cause. First, some basic anatomy. The lungs consist of tubes called "bronchi" which carry air down to tiny air sacs or alveoli which allow oxygen to cross through into the blood and carbon dioxide to leave in the breath. The bronchi are lined with a mucus-producing tissue that traps dust and germs and carries it out of the lungs. The alveoli have immune system cells to kill bacteria which may find their way into the lung.
Chronic bronchitis is characterized by inflammation in the air passages with excessive mucus production. The persistent inflammation eventually causes impaired airflow due narrowing of the airways. It becomes increasingly difficult to get air into and out of the lungs, resulting in a chronic cough and shortness of breath. The accumulation of mucus traps bacteria which can lead to recurrent lung infections which make the problem much worse. As the disease progresses, more air passages clog and breathing becomes increasingly difficult.
Emphysema is a disease lower in the lungs in the air sacs. Chronic inflammation damages the thin walls of the air sacs causing them to rupture. As more air sacs break apart, large segments of the lung are rendered nonfunctional. Air gets in but does not exchange oxygen for carbon dioxide and it stays trapped in the dilated spaces, effectively rendering these areas useless. As the damage progresses, the lungs become less able to do their job and shortness of breath gets worse. There can be components of chronic bronchitis and emphysema in the same person.
Asthma is a form of COPD due to inflammation of the airways, but most asthma comes from the immune system reacting to things in the air, such as pollen and dust. The inflammatory reaction causes the airways to constrict in addition to producing more mucus. This narrowing reduces the ability to get air in and out of the lungs. Asthma is called a "reversible" airway disease because the inflammation and constriction can be reversed with drugs that dilate the airways. However, longstanding inflammation in asthmatics can lead to the development of chronic bronchitis.
Why is COPD so prevalent and why are women developing it and dying from it in greater numbers? In a word: smoking. It takes decades to develop COPD and we now are seeing the effects of smoking on women who started smoking in the 1940s to the 1960s. Female smokers are 13 times more likely to die from COPD than nonsmokers. About 80 percent of COPD is from smoking.
Environmental pollution and second-hand smoke can be a factor in nonsmokers who develop COPD as can industrial factors, such as coal dust in the case of black lung disease. Genetics play a part also in how severe COPD becomes. One form of emphysema is caused by a deficiency of an enzyme, alpha1 antitrypsin, which inhibits enzymes designed to help us fight off bacteria. Unchecked, the enzymes attack the air sacs and destroy them. Alpha1 antitrypsin deficiency is inherited and can be detected through a blood test.
These diseases are diagnosed based on history of symptoms, an examination and a pulmonary function test. Treatment consists of inhaled and oral drugs to dilate the airways and reduce inflammation. In worse cases, supplemental oxygen can make daily living more comfortable and enable those affected to carry on normal activities. While symptoms can be improved, there is nothing to stop the disease progression, making avoidance of smoking critical. Waiting until symptoms develop to quit smoking is not a wise decision.
Quitting smoking now is the best way to prevent COPD. For current or former smokers who have a chronic cough or for whom modest exertion causes huffing and puffing, an examination and pulmonary function test can diagnose if COPD is contributing. Treatment can improve one's ability to function. For more information on COPD, go to the American Lung Association Web site at http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=35020 online.