Symptoms and Physiology
Because of the lungs' tremendous safety margin of extra tissue, emphysema usually has been present for years before it is diagnosed. Patients commonly have lost 50-70 percent of their lung tissue by the time symptoms alert them that something is wrong.
The first hint of emphysema is often a minor inconvenience in breathing. This gradually becomes worse until even the slightest exertion causes shortness of breath. Other hallmarks of the illness are fatigue, loss of weight, a "barrel-chested" appearance, and overdeveloped neck and shoulder muscles. These sympthoms and signs do not all occur in every patient. They are related to certain underlying physiologic events.
The respiratory system can be visualized as an upside-down tree consisting of a trunk (trachea), two main branches (bronchi) leading into the lungs, and progressively smaller branches (bronchioles).
At the tips of the bronchioles are tiny clusters of highly elastic air sacs known as alveoli. It is here that the lungs' primary function of gas exchange takes place--the delivery of freshly inhaled oxygen into the bloodstream and the elimination of the waste product carbon dioxide into the lungs so it can be exhaled.
In emphysema, the walls of the alveoli begin to be eaten away and to lose their elasticity. Groups of ruptured alveoli combine to form larger sacs which are poor gas exchangers. The respiratory muscles must work harder to bring in enough oxygen for the tissues and to get rid of carbon dioxide. More and more energy must be used for breathing, leading to fatigue and sometimes to loss of weight. Trapped air may give the chest the rounded appearance mentioned earlier. Accessory muscles in the neck and shoulders, exerted in laboring for air, become visibly more developed. The heart has to work harder, and it may enlarge and eventually give out, a major cause of death in severely ill emphysema patients.
The Biochemical Basis of Emphysema
Only in recent decades has medical science begun to learn about the biochemical processes leading to the development of emphysema. At the National Jewish Center for Immunology and Respiratory Medicine and other leading research centers, scientists have begun to unravel the mystery of how the disease occurs.
To summarize their finds briefly: Emphysema is intimately connected with the functioning of inflammatory cells. As part of the body's defense against disease, certain white blood cells release enzymes called proteases. The purpose of these powerful substances is to destroy bacteria, viruses and other foreign "invaders," but if not regulated properly, they can also harm healthy surrounding tissues.
Normally, after the proteases complete their work in the lung, they are inhibited by a protein called alpha-1-antitrypsin. But sometimes alpha-1-antitrypsin is missing or inactivated. The lack of activity by this important protein is the key to emphysema. When alpha-1-antitrypsin is not doing its job, proteases begin to attack the lung itself. They destroy elastin, a protein vital to maintaining the flexibility of the lung, and collagen, a part of the connective tissue. Little by little, the lung is eaten away.
Major Causes and Complicating Factors
Certain factors are known to play major roles in causing emphysema or making it worse. They either hamper the action of alpha-1-antirypsin, attract large numbers of white blood cells into vulnerable lungs, or both.
Smoking is by far the most common cause of emphysema. for decades many physicians have suspected this, knowing that people who smoke are much more likely than non-smokers to get the disease. In the past few years, researchers have developed strong direct evidence connecting emphysema with smoking. they have demonstrated that chemicals called oxidants, contained in cigarette smoke, can inactivate alpha-antitrypsin in the lung.
Not all cases of the illness are primarily due to smoking, however. Three to 5 percent of emphysema patients have a genetic defect resulting in severe alpha-1-antitrypsin deficiency. These people tend to develop symptoms in their 20s and 30s rather than in middle or old age as most other emphysema patients do. A blood test can identify members of this high-risk group as early as the first month of life. This test can be ordered as part of diagnostic evaluations at National Jewish and other major medical centers. Further study of genetic factors may reveal why a few people who smoke heavily all thier lives never develop emphysema, while others who smoke little or not at all seem to be highly susceptible.
A serious complicating factor for many people with emphysema is chronic bronchitis. In this disease, excess mucus collects in the bronchi, obstructing the flow of air and becoming a breeding ground for infections which bring numerous white cells into the lungs. Common symptoms of this condition are coughing and production of excess sputum. Chronic bronchitis and emphysema are frequently found together.
COPING WITH EMPHYSEMA
No medicine has yet been found to reverse or completely halt the destruction of lung tissue once emphysema has begun. But much can be done to eliminate or alleviate symptoms, to treat related, potentially complicating problems, and to slow down the course of the disease. Expert professional help and conscientious self-care can contribute to a better and longer life for the emphysema patient.
Protecting the Lungs
The most important thing a person with emphysema can do is to stop smoking. Studies have shown that giving up tobacco, even after having developed emphysema symptoms, considerably decreases the subsequent rate of damage to the lungs. Second-hand smoke and other respiratory irritants should also be avoided.
All emphysema patients, especially those who suffer from chronic bronchitis, must take great care to avoid respiratory infections or, if infections occur, to see that they are treated before they become serious. Antibiotics and other medicines may be prescribed for this purpose, and yearly influenza vaccinations are recommended. Fever, chills, or any changes in cough or sputum should be reported to the doctor immediately.
Practicing proper bronachial hygiene also prevents trouble. Regularly clearing secretions from respiratory and nasal passages is a must. Postural drainage--using gravity to help eliminate mucus from the lungs--is a useful technique practiced and taught by physical therapists specially trained to deal with pulmonary disease.
Many emphysema patients also have asthma, a reversible condition in which the airways become obstructed in response to various triggering factors such as allergies, chemical irritants, cold temperatures, or infections. Many of these patients benefit greatly from regular preventive use of medications called bronchodilators, drugs which keep the airways open. Corticosteroids are sometimes prescribed to reduce inflammation and swelling in the airways.
All medicines must be taken on schedule and administered as directed if they are to work most effectively. Patients should learn the proper way to use a nebulizer (sprayer) and follow and other instructions the doctor may provide. Over-the-counter remedies should be strictly avoided unless their use is supervised by a physician.
Regular medical checkups are important for emphysema patients. Using sophisticated pulmonary function tests, the doctor can monitor any changes in breathing or responses to medications and modify treatment accordingly.
Relieving Symptoms and Living a
The physician may prescribe oxygen to ease shortness of breath and raise the level of oxygen in the blood during exercise, at night, or at other times. Many patients benefit from training to use their respiratory muscles more efficiently, eliminating or reducing their need for supplemental oxygen.
A reconditioning program that gradually increases exercise tolerance also helps many emphysema patients, enabling them to live more normal, active lives. Occupational therapists can advise on ways to conserve energy while performing daily tasks at home and at work. Nutritional counselors can assist with weight-loss problems and maintenance of general good health.
Victims of serious chronic diseases and their families must deal with continual stress. For people in this situation, psycho-social counseling is often very beneficial.
Decades of experience at National Jewish have shown that treatment of emphysema is most successful when all of these types of therapy are carefully integrated in a "team" approach to care, and when patients and their families are active members of the team.
RESEARCH OFFERS HOPE
Over the past few decades, scientists at the world's foremost medical research institutes, including the National Jewish Center for Immunology and Respiratory Medicine, have made significant progress in understanding emphysema. Basic laboratory studies have uncovered the biochemical mechanisms involved in the illness, clearly showing the role that smoking plays in its development and holding out realistic hope that effective medications will be found. Worldwide clinical experience with millions of patients has led to improvements in the quality of medical and supportive care available to people with emphysema.
Continuing research promises that even more important advances will occur--and will come soon enough to help many of those who now must live with this difficult disease.
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|Publication:||Pamphlet by: National Jewish Center for Immunology and Respiratory Medicine|
|Date:||Jan 1, 1989|