Alternative Names COPD, chronic obstructive pulmonary disease
Definition Emphysema is a chronic disease in which the tissues of the lungs are gradually destroyed. These tissues are the walls of the alveoli, the air spaces where oxygen is exchanged with carbon dioxide in the blood. The ability of the lungs to provide oxygen to the body decreases. As a result, the person finds it increasingly difficult to breathe and to exercise without discomfort.
What is going on in the body? As in chronic bronchitis, emphysema is usually caused by years of cigarette smoking. No one knows why only 10% to 15% of smokers get emphysema. Scientists think that certain people are predisposed because of their genes. Another theory is that infections or asthma in childhood makes their airways more sensitive to damage. Some think that deeper inhalation of cigarette smoke may deposit more chemicals in the lungs.
Some people produce too little alpha-1-antitrypsin, a protective enzyme secreted in the lungs. These people are much more likely to develop emphysema at an early age, even without exposure to cigarette smoke.
What are the signs and symptoms of the disease? By the time emphysema is diagnosed, the person will have shortness of breath. Usually this is a feeling of not being able to catch their breath with various levels of exercise. Unless the disease is halted, by stopping smoking in most cases, the breathing problems will get worse. In many cases, people will find themselves breathless even at rest.
People with severe emphysema cannot catch their breath when they lie down to sleep. This is called orthopnea. It forces them to get what little rest they can while sitting propped on a pillow or sleeping in a chair.
What are the causes and risks of the disease? Except for rare cases caused by a lack of an enzyme, emphysema is a disease of smokers. The more years one smokes and the more cigarettes smoked, the greater the likelihood of developing emphysema.
What can be done to prevent the disease? Most emphysema can be prevented by not smoking. Smoke exposure should especially be avoided by people with alpha-1-antitrypsin deficiency.
How is the disease diagnosed? The diagnosis is based on a history of worsening shortness of breath. Chest X-rays can sometimes be helpful, but they are usually not abnormal until late in the disease. The lungs look enlarged because the destruction of the alveoli results in trapping of air. Sometimes, large areas of destruction may be seen in the lungs, which can look like Swiss cheese. Lung function tests are sometimes used to measure how well the lungs are working.
What are the long-term effects of the disease? Eventually, severe shortness of breath will limit the person's normal daily activities. People who continue to smoke will have worsening shortness of breath. They may have panic attacks when they are unable to get enough air in and out. People with advanced emphysema are often incapacitated. They are short of breath even when confined to a chair or bed.
What are the risks to others? There are few risks to other people living in the same household as someone with emphysema. The main danger is the exposure to second-hand smoke from someone whose emphysema is caused by cigarette smoking.
What are the treatments for the disease? Once the lung is destroyed, it does not repair itself.
The main treatment for emphysema is to eliminate any irritants. In order to see any improvement, the person must stop smoking. It is also important to stop exposure to any dust, dirt, or fumes.
Some people improve with regular corticosteroid treatment, such as oral prednisone tablets or inhalers such as beclomethasone. Those who do not improve after a trial of corticosteroids may not be continued on long-term treatment, as the side effects may outweigh the benefits.
In a few people, treatment with bronchodilators, such as salbutamol, produces an improvement in lung function tests of 10% or more. Bronchodilators are used to widen the airways in reversible airway diseases such as asthma. They are often ineffective in emphysema or chronic bronchitis, another serious lung disease related to smoking.
Most people will benefit from rehabilitation therapy to enable them to use their energy more efficiently, in a way that requires less oxygen. Many people also use oxygen therapy. This has been shown to improve survival, especially in those with advanced disease.
Sometimes surgery is used to remove nonfunctional areas of lung tissue. Even without this lung tissue, many people have considerable improvement in their breathing ability.
If a person has alpha-1-antitrypsin deficiency, or is a carrier, it is absolutely critical to avoid smoking. Intravenous replacement of the enzyme helps some people, but it is quite expensive.
What are the side effects of the treatments? Side effects depend on which medications are used. Bronchodilators can cause a rapid heart rate and trembling of the hands.
Corticosteroids can predispose people to infections and cause other medical problems. They are only used in people who show good responses to the treatment.
What happens after treatment for the disease? Treatments can improve the symptoms, but they will not reverse the damage to the lungs. The best the person with emphysema can hope for is that quitting smoking will keep the disease from progressing.
How is the disease monitored? Lung function tests may be useful for measuring how the lungs are working. Chest X-rays may also be used to look for 3 common diseases that complicate emphysema: heart disease, pneumonia, and lung cancer.
Author: William M. Boggs, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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