Multiple: Emphysema

Definition
Description
Demographics
Causes and Symptoms
Diagnosis
Treatment
Prognosis
Prevention
The Future
For more information

Definition

Emphysema is a form of progressive lung disease that is characterized by chronic shortness of breath and long-term disability. It is sometimes grouped together with chronic bronchitis under the name of chronic obstructive pulmonary disease, or COPD. Many people who are diagnosed with emphysema also have chronic bronchitis.

Description

Emphysema is a lung disease in which a person's ability to breathe easily and deeply is steadily weakened over time by the destruction of lung tissue. The human lung consists of tissue containing millions of tiny air sacs called alveoli, which are arranged like bunches of grapes around very

small air tubes called bronchioles. There are about 300 million alveoli in each lung. When a person breathes in air, the air travels from the nose and mouth through the windpipe and then into the right and left bronchi, which are the main air passages into each of the two lungs. The bronchi divide and subdivide repeatedly into smaller and smaller air passages, finally ending in the bronchioles and alveoli.

In a healthy person, oxygen from the air that has been taken in is exchanged in the walls of the alveoli for carbon dioxide in the person's blood. When the person breathes out, the carbon dioxide leaves the body in the air that travels out from the lungs and through the upper airway to the nose and mouth.

To perform its function effectively, the tissue in the lungs that separates the alveoli from one another needs to be as elastic as possible. The alveoli contain tiny elastic fibers in their cell walls that allow them to act like miniature balloons. What happens in emphysema is that smoke or other irritants causes the alveoli to become inflamed and lose their elasticity. The bronchioles start to collapse, which traps air inside the alveoli and overstretches them. In time the alveoli rupture, leading to the formation of fewer but larger air sacs in the lungs. These larger and less flexible sacs are less efficient in forcing air out of the lungs when the person breathes out. As a result, the person has to breathe more frequently or

breathe harder in order to get enough oxygen and get rid of carbon dioxide.

In addition to the loss of elasticity in the alveoli, the cells in the airways secrete more mucus than usual, which collects in the airways and clogs them, making breathing even more difficult.

The High Cost of Emphysema

Emphysema has claimed the lives of many noteworthy people in the twentieth and twenty-first centuries:

• Actors: Tallulah Bankhead, Paulette Goddard, Robert Mitchum, Vincent Price, Barbara Stanwyck, Spencer Tracy
• Entertainers: Johnny Carson, Arthur Godfrey, Dean Martin, Allan Sherman
• Musicians: Leonard Bernstein
• Politicians and public figures: William O'Neill, Patricia Nixon (wife of President Richard Nixon), Coleman Young
• Writers and poets: Samuel Beckett, William F. Buckley, Jr., Erskine Caldwell, T. S. Eliot, Robert Heinlein

Demographics

Emphysema is increasing in the United States and other developed countries primarily because of cigarette smoking. It is almost entirely a disease of adults. About 12 million adults in the United States have been diagnosed with the disease; however, many doctors believe emphysema is underdiagnosed. Between 4 and 6 percent of male adults and 1 to 3 percent of female adults are estimated to have emphysema. The number of women diagnosed with the disease is rising rapidly; the year 2000 was the first year that more women than men were identified as having emphysema. About 120,000 people die each year in the United States from emphysema.

People who develop emphysema as a result of smoking generally start to have symptoms in their late forties or early fifties. Those who have emphysema because of a genetic condition (described later) may begin to have symptoms in their thirties. This genetic condition, known as alpha 1-antitrypsin deficiency, is more common in Caucasians than in members of other races and accounts for about 2 percent of all emphysema cases in the United States.

Some people who do not smoke cigarettes are at increased risk of emphysema. They include:

• People who work in occupations that expose them to high levels of dust from grain or cotton, or chemical irritants. These occupations include mining, certain types of agricultural work, and lumbering.
• People exposed to high levels of automobile exhaust or secondhand smoke.
• People with certain diseases that affect connective tissue, such as Marfan syndrome.

Causes and Symptoms

Emphysema is caused by a weakening of the tissues in the lungs as a result of inflammation due to smoke or other chemical irritants in the air, or a hereditary deficiency of a protein that protects the elasticity of lung tissue. As the bronchioles in the lungs collapse and the alveoli become enlarged, the lungs become less efficient in getting rid of carbon dioxide and the person has to breathe more frequently in order to get enough oxygen. In addition, the person has to use his or her chest muscles to expel air from the lungs forcefully rather than being able to rely on the normal movement of the diaphragm during breathing. This need to use muscular force leads to the development of a so-called barrel chest; that is, the person's chest is almost the same size from front to back as from side to side.

About 2 percent of cases of emphysema are caused by a deficiency of a liver enzyme known as alpha 1-antitrypsin, or A1AT. The enzyme ordinarily protects the alveoli in the lungs from damage by another enzyme that harms connective tissue. In people with A1AT deficiency, there is not enough of the protective enzyme to keep the alveoli in good working condition. A1AT is an inherited condition caused by a mutation in a gene on chromosome 14.

In addition to shortness of breath, coughing, and wheezing, people with emphysema often develop the following symptoms:

• Pursed-lips breathing. This is a way of partially closing the lips that allows the person to fully exhale. When the mouth opening is smaller, the airways that have been weakened by the disease open wide and allow the person to expel more air from the lungs.
• Greater difficulty exercising or doing work that requires physical activity.
• Loss of appetite and weight loss. Eating can make it harder to breathe because the stomach expands during a meal and pushes upward against the diaphragm.
• Fatigue. Emphysema leads to a lower level of oxygen in the blood, which in turn causes people to feel tired easily.
• Slow recovery from such upper respiratory infections as colds and flu.

It is important to note that emphysema is a disease that develops gradually; thus its symptoms may take years to become bothersome enough to send the patient to their doctor.

Diagnosis

Emphysema is most often diagnosed by pulmonary function tests or PFTs. These are tests in which the patient is asked to breathe into a device called a spirometer. The spirometer measures how much air the patient'slungs can hold and how fast the air moves in and out of the lungs. It can also be used to determine how well the lungs are exchanging oxygen and carbon dioxide. Another way the spirometer can be used is to test the effectiveness of inhaled medications in treating the patient'semphysema.

Patients are also typically given a chest x ray or computed tomography (CT) scan to look for damage to lung tissue and the possible presence of a lung infection. To measure the amount of oxygen and carbon dioxide in the patient's blood, he or she may be given a type of blood test called the arterial blood gases test. This test can help the doctor evaluate the severity of the patient's emphysema.

Treatment

There is no cure for emphysema. Treatment is focused on slowing the progress of the disease and easing the patient's symptoms. The first part of treatment for patients who smoke is to quit the habit.

The next stage in treatment is the use of medications. The doctor may prescribe one or more of the following types of drugs:

• Bronchodilators. Bronchodilators are drugs that work by opening up the airways, which allows for more efficient exchange of carbon dioxide and oxygen. Some are taken in tablet form while others are dispensed in inhalers. Depending on the severity of the person's emphysema, patients may use the inhaler only when needed for shortness of breath or they may take a dose of the medication at prescribed regular intervals.
• Steroids. This type of medication works by lowering the inflammation in the tissues lining the airways. These drugs can also be taken in pill form or through inhalers.
• Antibiotics. People who have infections in the lungs as well as emphysema may be given antibiotics to treat the infections.
• Oxygen. Patients who have severe attacks of emphysema may need to go to the hospital for oxygen therapy. There are also oxygen tanks that can be used in the home; some of these are portable units.

Emphysema is sometimes treated surgically. In some cases, part of the diseased lung is removed. This procedure creates space for the remaining portions of the lungs; it does improve breathing and quality of life for some patients. Another surgical option is lung transplantation. This is a risky procedure, however, and requires the patient to take medications to prevent the rejection of the transplanted lung. In addition, not everyone qualifies for transplantation, and those who do are limited by the short supply of available organs.

Another important part of treatment for emphysema is called pulmonary rehabilitation. It is aimed at educating patients about their disease and helping them with lifestyle changes that will slow the progression of the disease and improve quality of life. Pulmonary rehabilitation includes a physical exercise program designed to improve the patient's physical endurance and energy level. Many patients are also encouraged to lose weight in order to reduce the burden on their lungs. One important benefit of pulmonary rehabilitation is psychological: Patients report that their self-esteem and sense of control over their life improve when they start to see benefits from the rehabilitation program.

Prognosis

Emphysema is known to shorten a patient's lifespan. It is the fourth most common cause of death in the United States as of 2008, being responsible for 4.5 percent of all deaths and a contributing factor in another 4.3 percent. Some patients, however, live longer than others depending on the cause of their emphysema and the measurement of their lung capacity at diagnosis. Patients who have smoked twenty cigarettes per day for twenty years or longer with a severely reduced breathing capacity have the worst prognosis; only 5 percent survive for twelve years after diagnosis.

Prevention

Most cases of emphysema can be prevented by simply not smoking or by quitting smoking as soon as possible and avoiding secondhand smoke. Emphysema related to genetic factors cannot always be prevented, but its development can be postponed in people who inherited the defective gene by avoiding smoking.

WORDS TO KNOW

Alveolus (plural, alveoli) : The medical term for one of the tiny air sacs in the lungs where oxygen is transferred from the lungs to the blood and carbon dioxide is removed.

Bronchiole : A very small thin-walled air passage in the lungs that branches off from a bronchus.

Bronchus (plural, bronchi) : One of the two major divisions of the airway that lead into the right and left lungs.

Diaphragm : A sheet of muscle tissue that divides the chest cavity from the abdominal cavity.

Progressive : A term that refers to a disease that gets worse over time.

Spirometer : A device that is used to test the air capacity of a person's lungs and the amount of air that enters and leaves the lungs during breathing.

The Future

Emphysema is likely to continue to rise in the United States because of the numbers of long-term female smokers who are now getting to the age when the symptoms of emphysema appear. In addition, the rates of emphysema around the world are predicted to rise rapidly over the next few decades as more and more people take up smoking. It is possible that

more effective drugs will be developed to treat emphysema, but a cure for the disease is unlikely in the near future.

SEE ALSO Bronchitis; Marfan syndrome; Smoking

For more information

BOOKS

Hedrick, Hannah L., and Austin Kutcher. The Quiet Killer: Emphysema, Chronic Obstructive Pulmonary Disease. Lanham, MD: Scarecrow Press, 2002.

Matthews, Dawn D. Lung Disorders Sourcebook: Basic Information for Consumers. Detroit: Omnigraphics, 2002.

Quinn, Campion E. 100 Questions and Answers about Chronic Obstructive Pulmonary Disease (COPD). Sudbury, MA: Jones and Bartlett Publishers, 2006.

PERIODICALS

Grady, Denise. “From Smoking Boom, a Major Killer of Women.” New York Times, February 12, 2008. Available online at http://health.nytimes.com/ref/health/healthguide/COPD_ess.html (accessed June 4, 2008).

Olsen, Erik, and Denise Grady. “Gasping for Air: Life with COPD.” New York Times, November 2007. Available online at http://video.on.nytimes.com/index.jsp?fr_story=39f9d444e3cdfaac1fcebdfa4b506cce31786094 (accessed June 5, 2008). This is a video interview of a woman diagnosed with emphysema in 2007. It takes about five minutes and thirty seconds to play.

WEB SITES

American Lung Association. Chronic Obstructive Pulmonary Disease (COPD) Fact Sheet. Available online at http://www.lungusa.org/site/apps/nlnet/content3.aspx?c=dvLUK9O0E&b=2060053&content_id={EE451F66-996B-4C23-874D-BF66586196FF}&notoc=1 (updated September 2007; accessed June 5, 2008).

National Emphysema Foundation. COPD. Available online at http://www.emphysemafoundation.org/?page_id=28 (accessed June 5, 2008). Includes detailed information about the different tests of lung function and the various types of medications for treating emphysema.

National Heart, Lung, and Blood Institute (NHLBI). COPD: Are You at Risk? Available online at http://www.nhlbi.nih.gov/health/public/lung/copd/campaign-materials/html/copd-atrisk.htm (accessed June 5, 2008).

National Heart, Lung, and Blood Institute (NHLBI). COPD: Breathing Better with a COPD Diagnosis. Available online in PDF format at http://www.nhlbi.nih.gov/health/public/lung/copd/campaign-materials/pub/copd-patient.pdf (updated December 2006; accessed June 5, 2008).

National Heart, Lung, and Blood Institute (NHLBI). Educational Video about COPD. Available online at http://www.nhlbi.nih.gov/health/public/lung/copd/campaign-materials/index.htm (requires RealPlayer; accessed June 5, 2008). This nine-minute video profile follows three people diagnosed with COPD; includes description of the way the lungs work.