CHRONIC RESPIRATORY DISEASES

Chronic respiratory diseases include disorders that affect any part of the respiratory system, not only the lung but also the upper airway (nose, mouth, pharynx, larynx, and trachea), the chest wall and diaphragm, and the neuromuscular system that provides the power for breathing. Prolonged (chronic) diseases and disorders of the respiratory system in adults are those conditions that are present for months to years, and are treatable but generally not curable. Successful medical management of any chronic respiratory disease depends upon evaluating the patient as a whole and assessing the structure and function of the entire respiratory system.

The chronic diseases of the respiratory system collectively result in profound human suffering, mortality, and economic loss. For example, an estimated 163,000 Americans will die of cancer of the respiratory system in 2001. Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States (behind heart diseases, cancer, and stroke) and now kills about 113,000 Americans annually. The death rate from COPD rose 44.5 percent between 1979 and 1997, an increase that was the highest among the top ten causes of death in the United States. Experts estimate that about 30 million Americans have COPD, and only about half of these have been evaluated and diagnosed. The total economic impact of COPD in the country is estimated to be about $31.9 billion annually.

The huge impact of lung cancer, COPD, and other chronic respiratory diseases in our society is especially sobering in light of the fact that many of these conditions are preventable. The use of tobacco is the leading cause of preventable illness and death in the United States, accounting for about 430,000 deaths, or about 20 percent of all deaths, annually. Cigarette smoking is the primary risk factor for the development of COPD and lung cancer. About 25 percent of all Americans smoke cigarettes, and, tragically, 3,000 young Americans take up the smoking habit every day, greatly increasing their risk of dying prematurely from COPD, lung cancer, heart disease, or some other smoking-related disease. It is alarming that the percentage of high school and college students who smoke cigarettes increased during the early 1990s.

There are relatively few symptoms of respiratory disease, whether it be acute or chronic, as a diseased respiratory system has a limited number of clinical expressions. These include shortness of breath (dyspnea); cough, with or without phlegm (sputum) production; high-pitched continuous

Figure 1

breathing noise (wheezing); chest tightness; coughing up blood (hemoptysis); and chest pain. Uncommonly, patients with chronic respiratory disease are free of symptoms (asymptomatic) but have a disease process that is discovered incidentally, such as by a routine chest X-ray. Respiratory symptoms may be the early warning sign of chronic respiratory disease, but, unfortunately, they are commonly ignored, dismissed as being normal, or mistakenly attributed to aging or alternative disorders.

The medical evaluation of a patient with a suspected chronic respiratory disease starts with the physician's taking a detailed medical history, with particular attention to the symptoms listed above and their timing (see Figure 1). A thorough history of respiratory illness always includes attention to relevant factors such as tobacco use, occupational and environmental exposure to noxious respiratory agents, travel, hobbies, immunizations, family medical history, current and prior medications, general medical health, and comorbid conditions, to name just a few relevant components. The medical history is followed by a physical examination, which must be complete in order to detect both pulmonary and nonpulmonary clues to the presence of a disease process. It is important to emphasize that pulmonary disorders, whether acute or chronic, may originate in the lung or secondarily involve the lung after originating in another part of the body. Diagnostic testing supplements the medical history and physical examination. A wide range of diagnostic tests is now available to help the physician diagnose a specific respiratory system disease correctly.

There are hundreds of different chronic respiratory diseases. Table 1 provides an outline of their major headings and a few important examples of each category. The list is not intended to be complete, and the reader is referred to medical textbooks or electronic sources for a more complete listing. The remainder of this section will address briefly a few of the most important chronic respiratory diseases.

COPD. Chronic obstructive pulmonary disease is the most important and common of the chronic respiratory diseases. Remarkably, few Americans know what COPD is. This condition has been defined as "a disease state characterized by the presence of airflow obstruction due to chronic bronchitis or emphysema; the airflow obstruction is generally progressive, may be accompanied by airway hyperreactivity, and may be partially reversible" (American Thoracic Society, 1995). Most patients with COPD have smoked at least one pack of cigarettes daily for twenty years or longer. By their fifth or sixth decade of life they suffer from dyspnea, productive cough (often worse in the morning), difficulty in clearing sputum from the airways, wheezing, or any combination of these symptoms. Slowly and gradually the symptoms progress year by year and are often mistakenly attributed to increasing age or to another disease such as asthma. Initially, the dyspnea occurs only with extreme exertion, but eventually, in severe cases, it limits simple activities such as changing clothes, raising the arms above the head, bending over, or taking a shower. The diagnosis of COPD may be made by the medical history, physical examination, pulmonary function tests, and a chest X-ray, after exclusion of other conditions such as asthma, bronchiectasis, lung cancer, and congestive heart failur.

Essential steps in managing COPD are outlined in Table 2. Smoking cessation slows the agerelated rate of loss of pulmonary function in middle-aged smokers with mild COPD. In COPD patients with low blood oxygen levels (hypoxemia), continuous oxygen therapy prolongs survival. All other treatment approaches are aimed at improving symptoms. No treatment intervention restores lung function to normal. Intense rehabilitation of patients with severe COPD provides temporary improvement in symptoms. Surgical treatment options are limited to a very small fraction of COPD patients and outcome benefits are the focus of ongoing research. Without treatment, COPD pursues a downhill course leading to premature disability and death.

Cancer. Cancer represents another broad category of chronic respiratory disease. Cancer may affect any part of the respiratory tract, including the larynx. Cancer that involves the lung is called "primary" if it originates in the lung and "secondary" if it spreads to the lung from another site. Primary lung cancer usually develops from the epithelial lining of the bronchi (bronchogenic carcinoma). Rarely it originates from the lung's soft tissues or the outer lining on the lung's surface (malignant mesothelioma). The layman's term "lung cancer" usually refers to bronchogenic carcinoma, a deadly chronic disease that in about 90 percent of cases is caused by cigarette smoking.

Patients with bronchogenic carcinoma have a wide variety of initial clinical manifestations, but a typical presentation is a new or changing respiratory symptom in combination with an abnormal chest X-ray. Loss of appetite and weight loss are common. Unfortunately, by the time most patients (about 75%) seek medical attention, the lung cancer cannot be entirely removed by surgery (unresectable) because it has spread in the chest or elsewhere in the body (the stage of the cancer is advanced). Or, the patient may be too ill to tolerate chest surgery because of the systemic effects of

Table 1

the cancer or another smoking-related condition such as COPD or heart disease. Anticancer drug therapy (chemotherapy), radiation therapy, and other treatment methods may provide temporary improvement in the size of the cancer (remission), diminution of symptoms (palliation), or slightly improved survival. Nevertheless, cure of lung cancer by nonsurgical approaches is rare, and most patients with unresected lung cancer die prematurely from the disease. Overall, only 14 percent of patients with lung cancer survive for five years.

Infiltrative Lung Disease. Another broad category of chronic respiratory disease is infiltrative lung disease, in which shadows (infiltrates) appear in the lung tissue on the standard chest X-ray. Infiltrates are caused by the accumulation of cells or fluids in parts of the lung in excess of their normal amount. Infiltrates may be localized (focal) or widespread (diffuse—involving all five lobes of the lung). They may involve the lung's tissue framework ("interstitial" infiltrate), airspace ("alveolar" infiltrate), or both. Well over one hundred specific lung diseases fall into the category of infiltrative disease, which may be acute or chronic; many of them are occupational in origin. The chronic infiltrative diseases share many similar findings, among which are unrelenting dyspnea (sometimes with a dry cough); abnormal lung sounds (crackles) on chest physical examination; reduced amount of air in the lung (restrictive dysfunction) and reduced gas transfer (diffusing capacity) on pulmonary function testing; and hypoxemia, especially with exercise.

Idiopathic Pulmonary Fibrosis (IPF). A lung scarring of unknown cause, IPF is the prototype of the chronic infiltrative pulmonary diseases, just as COPD is the prototype of the chronic airway diseases. IPF affects men and women between the ages of fifty and seventy. The prevalence of IPF has been estimated to be three to six cases per 100,000 people. Although the exact cause of this disease is not known, cigarette smoking is a suspected risk factor. Progressive dyspnea, dry cough, and crackles on physical examination are typical clinical features of this disease. Patients with suspected IPF are often evaluated with high-resolution computed tomography (HRCT) imaging, which displays patchy scarring below the lung surface, especially in the lower lung zones. Biopsy of lung tissue via the airway (flexible fiberoptic bronchoscopy)

Table 2

or via the chest wall (video-assisted thoracic surgery) is often employed to confirm the clinical impression. Treatment of this condition is mainly supportive, as the scarring itself is not reversible. Continuous supplemental oxygen is helpful in reducing dyspnea. Anti-inflammatory therapy with corticosteroids or immunosuppressive agents is frequently attempted, but results are usually disappointing. Treatment with interferon has been investigated. Lung transplantation is an option for a few patients with IPF. Most patients with IPF have a poor prognosis, and median survival is about five years.

Ventilatory Control Disorders. The rate, depth, and rhythm of normal breathing are exquisitely controlled by a complex interplay of regulatory mechanisms in the brain, the respiratory system, the great blood vessels, and other parts of the body. Disturbances in any of these mechanisms may lead to altered breathing (ventilatory) control, sometimes with disastrous consequences. A number of chronic respiratory disorders may be attributed to abnormal control of ventilation, including sleep apnea and obesity-hypoventilation syndrome.

The most common and important disorder of ventilatory control is sleep apnea syndrome. An apnea is defined as cessation of airflow at the nose and mouth for more than ten seconds, and an hypopnea is a drop of oxyhemoglobin saturation of more than 4 percent with reduced air-flow. Obstructive apneas occur because of temporary closure of the throat (pharynx) and central apneas occur because of a transient reduction in breathing effort. The consequences of apneas and hypopneas during sleep are nocturnal hypoxemia and poor sleep quality. Sleep apnea is confirmed by performing recordings of physiological variables during sleep (polysomnography). An excessive number of apneas and hypopneas during a night of sleep defines sleep apnea. Sleep apnea syndrome is present when sleep apnea is accompanied by associated symptoms, including loud and cyclical snoring, excessive daytime sleepiness and daytime sleep attacks, morning sluggishness, daytime fatigue or tiredness, neuropsychological impairment, and declines in personality.

Obstructive sleep apnea is very prevalent, being found in 24 percent of middle-aged men and 9 percent of middle-aged women. Obstructive sleep apnea syndrome (OSAS) occurs in 4 percent of men and 2 percent of women. Overweight middle-aged and older men are most commonly affected. Hypoxemia during sleep and sleep disruption may be so severe as to cause daytime problems, particularly excessive and inappropriate sleepiness. Patients with OSAS may fall asleep while driving a car, operating machinery, or performing a job. Substantial psychosocial consequences may follow, including personality changes, marital stress, and loss of employment. The medical consequences of OSAS include high blood pressure in the lung (pulmonary hypertension), and in the body as a whole (systemic hypertension); failure of the right side of the heart; heart rhythm disturbances; and cardiovascular complications (stroke, myocardial infarction, and sudden death).

Treatment of OSAS consists of general measures such as patient education, weight loss, avoidance of alcohol and hypnotic medication, surgical relief of mechanical upper airway obstruction, and improved sleep habits. Many patients with OSAS are treated with nocturnal use of nasal continuous positive airway pressure (nasal CPAP) masks that stent the airway open during sleep, precluding pharyngeal obstruction. Dramatic improvement in symptoms is commonly observed. Results of treatment of central sleep apnea syndrome are less encouraging.

Obesity hypoventilation ("Pickwickian") syndrome is a disorder of ventilatory control in patients with moderate to severe obesity. This condition is thought to be caused by blunted breathing effort (ventilatory drive) and the mechanical load placed on the chest wall and abdomen by obesity. This disorder occurs in only a small percent of patients with obesity. The daytime hypoxemia and elevated blood carbon dioxide levels (hypercapnia) found in this condition may improve with significant weight loss. Patients with this condition also suffer from OSAS.

In conclusion, chronic respiratory diseases are very prevalent in our society. They cause untold suffering, premature death, and economic harm to patients, their families, and the nation. Chronic obstructive pulmonary disease, lung cancer, idiopathic pulmonary fibrosis, and obstructive sleep apnea syndrome are common examples of these chronic respiratory diseases. Treatment for these conditions is difficult and expensive, but successful management provides substantial symptomatic benefit for most patients. Many of the chronic respiratory diseases could be prevented by elimination of cigarette smoking.

John L. Stauffer

(see also: Asthma; Bronchitis; Lung Cancer; Occupational Lung Disease; Pulmonary Function; Smoking Behavior; Smoking Cessation; Tobacco Control )

Bibliography

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—— (2000). "Idiopathic Pulmonary Fibrosis: Diagnosis and Treatment. International Consensus Statement." American Journal of Respiratory and Critical Care Medicine 161 (2):646–664.

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Young, T.; Palta, M.; Dempsey, J.; Skatrud, J.; Weber, S.; and Badr, S. (1993). "The Occurrence of Sleep-disordered Breathing Among Middle-aged Adults." New England Journal of Medicine 328 (17):1230–1235.

Chronic Obstructive Lung Disease

Definition

Chronic obstructive lung disease, also known as chronic obstructive pulmonary disease (COPD), is a general term for a group of conditions in which there is persistent difficulty in expelling (or exhaling) air from the lungs. COPD commonly refers to two related, progressive diseases of the respiratory system, chronic bronchitis and emphysema. Because smoking is the major cause of both diseases, chronic bronchitis and emphysema often occur together in the same patient.

Description

COPD is one of the fastest-growing health problems. Nearly 16 million people in the United States, 14 million with chronic bronchitis and two million with emphysema, suffer from COPD. COPD is responsible for more than 96,000 deaths annually, making it the fourth leading cause of death. Although COPD is more common in men than women, the increase in incidence of smoking among women since World War II has produced an increase in deaths from COPD in women. COPD has a large economic impact on the healthcare system and a destructive impact on the lives of patients and their families. Quality of life for a person with COPD decreases as the disease progresses.

Chronic bronchitis

In chronic bronchitis, chronic inflammation caused by cigarette smoking results in a narrowing of the openings in the bronchi, the large air tubes of the respiratory system, and interferes with the flow of air. Inflammation also causes the glands that line the bronchi to produce excessive amounts of mucus, further narrowing the airways and blocking airflow. The result is often a chronic cough that produces sputum (mainly mucus) and shortness of breath. Cigarette smoke also damages the cilia, small hair-like projections that move bacteria and foreign particles out of the lungs, increasing the risk of infections.

Emphysema

Emphysema is a disease in which cigarette smoke causes an overproduction of the enzyme elastase, one of the immune system's infection-fighting biochemicals. This results in irreversible destruction of a protein in the lung called elastin which is important for maintaining the structure of the walls of the alveoli, the terminal small air sacs of the respiratory system. As the walls of the alveoli rupture, the number of alveoli is reduced and many of those remaining are enlarged, making the lungs of the patient with emphysema less elastic and overinflated. Due to the higher pressure inside the chest that must be developed to force air out of the less-elastic lungs, the bronchioles, small air tubes of the respiratory system, tend to collapse during exhalation. Stale air gets trapped in the air sacs and fresh air cannot be brought in.

Causes and symptoms

There are several important risk factors for COPD:

• Lifestyle. Cigarette smoking is by far the most important risk factor for COPD (80% of all cases). Cigar and pipe smoking can also cause COPD. Air pollution and industrial dusts and fumes are other important risk factors.
• Age. Chronic bronchitis is more common in people over 40 years old; emphysema occurs more often in people 65 years of age and older.
• Socioeconomic class. COPD-related deaths are about twice as high among unskilled and semi-skilled laborers as among professionals.
• Family clustering. It is thought that heredity predisposes people in certain families to the development of COPD when other causes, such as smoking and air pollution, are present.
• Lung infections. Lung infections make all forms of COPD worse.

In the general population, emphysema usually develops in older individuals with a long smoking history. However, there is also a form of emphysema that runs in families. People with this type of emphysema have a hereditary deficiency of a blood component, an enzyme inhibitor called alpha-1-antitrypsin (AAT). This type of emphysema is sometimes called "early onset emphysema" because it can appear when a person is as young as 30 or 40 years old. It is estimated that there are between 75,000 and 150,000 Americans who were born with AAT-deficiency. Of this group, emphysema afflicts an estimated 20,000-40,000 people (1-3% of all cases of emphysema). The risk of developing emphysema for an AAT-deficient individual who also smokes is much greater than for others.

The first symptoms of chronic bronchitis are cough and mucus production. These symptoms resemble a chest cold that lingers on for weeks. Later, shortness of breath develops. Cough, sputum production, and shortness of breath may become worse if a person develops a lung infection. A person with chronic bronchitis may later develop emphysema as well. In emphysema, shortness of breath on exertion is the predominant early symptom. Coughing is usually minor and there is little sputum. As the disease progresses, the shortness of breath occurs with less exertion, and eventually may be present even when at rest. At this point, a sputum-producing cough may also occur. Either chronic bronchitis or emphysema may lead to respiratory failure—a condition in which there occurs a dangerously low level of oxygen or a serious excess of carbon dioxide in the blood.

Diagnosis

The first step in diagnosing COPD is a good medical evaluation, including a medical history and a physical examination of the chest using a stethoscope. In addition, the doctor may request one or more of the following tests:

Pulmonary function test

Using a spirometer, an instrument that measures the air taken into and exhaled from the lungs, the doctor will determine two important values: (1) vital capacity (VC), the largest amount of air expelled after the deepest inhalation, and (2) forced expiratory volume (FEV1), the maximum amount of air expired in one second. The pulmonary function test can be performed in the doctor's office, but is expensive.

Chest x ray

Chest x rays can detect only about half of the cases of emphysema. Chest x rays are rarely useful for diagnosing chronic bronchitis.

Blood gas levels

Blood may be drawn from an artery (more painful than drawing blood from a vein) to determine the amount of oxygen and carbon dioxide present. Low oxygen and high carbon dioxide levels are often indicative of chronic bronchitis, but not always of emphysema.

Tests for cause of infection

If infection is present, blood and sputum tests may be done to determine the cause of infection.

Electrocardiogram (ECG)

Many patients with lung disease also develop heart problems. The ECG identifies signs of heart disease.

Treatment

The precise nature of the patient's condition will determine the type of treatment prescribed for COPD. With a program of complete respiratory care, disability can be minimized, acute episodes prevented, hospitalizations reduced, and some early deaths avoided. On the other hand, no treatment has been shown to slow the progress of the disease, and only oxygen therapy increases survival rate.

Drugs

Medications frequently prescribed for COPD patients include:

• Bronchodilators. These agents open narrowed airways and offer significant symptomatic relief for many, but not all, people with COPD. There are three types of bronchodilators: Beta2 agonists, anticholinergic agents, and theophylline and its derivatives. Depending on the specific drug, a bronchodilator may be inhaled, injected, or taken orally.
• Corticosteroids. Corticosteroids, usually inhaled, block inflammation and are most useful for patients with chronic bronchitis with or without emphysema. Steroids are generally not useful in patients who have emphysema.
• Oxygen replacement. Eventually, patients with low blood oxygen levels may need to rely on supplemental oxygen from portable or stationary tanks.
• Antibiotics. Antibiotics are frequently given at the first sign of a respiratory infection, such as increased sputum production or a change in color of sputum from clear to yellow or green.
• Vaccines. To prevent pulmonary infection from viruses and bacteria, people with COPD should be vaccinated against influenza each year at least six weeks before flu season and have a one-time pneumococcal (pneumonia ) vaccine.
• Expectorants. These agents help loosen and expel mucus secretions from the airways.
• Diuretics. These drugs are given to prevent excess water retention in patients with associated right heart failure.
• Augmentation therapy (for emphysema due to AAT-deficiency only). Replacement AAT (Prolastin), derived from human blood which has been screened for viruses, is injected weekly or bimonthly for life.

Surgery

Surgical procedures for emphysema are very rare. They are expensive and often not covered by insurance. The great majority of patients cannot be helped by surgery, and no single procedure is ideal for those who can be helped. In January of 1996, the government temporarily suspended Medicare payments for lung reduction surgery.

• Lung transplantation. Lung transplantation has been successfully employed in some patients with end-stage COPD. In the hands of an experienced team, the one-year survival rate is over 70%.
• Lung volume reduction. These procedures remove 20-30% of severely diseased lung tissue; the remaining parts of the lung are joined together. Mortality rates can be as high as 15% and complication rates are even higher. When the operation is successful, patients report significant improvement in symptoms.

Pulmonary rehabilitation

A structured, outpatient pulmonary rehabilitation program improves functional capacity in certain patients with COPD. Services may include general exercise training, administration of oxygen and nutritional supplements, intermittent mechanical ventilatory support, continuous positive airway pressure, relaxation techniques, breathing exercises and techniques (such as pursed lip breathing), and methods for mobilizing and removing secretions.

Alternative treatment

For both chronic bronchitis and emphysema, alternative practitioners recommend diet and nutritional supplements, a variety of herbal medicines, hydrotherapy, acupressure and acupuncture, aromatherapy, homeopathy, and yoga.

Prognosis

COPD is a disease that can be treated and controlled, but not cured. Survival of patients with COPD is clearly related to the degree of their lung function when they are diagnosed and the rate at which they lose this function. Overall, the median survival is about 10 years for patients with COPD who have lost approximately two-thirds of their lung function at diagnosis.

Prevention

Lifestyle modifications that can help prevent COPD, or improve function in COPD patients, include: quitting smoking, avoiding respiratory irritants and infections, avoiding allergens, maintaining good nutrition, drinking lots of fluids, avoiding excessively low or high temperatures and very high altitudes, maintaining proper weight, and exercising to increase muscle tone.

Resources

PERIODICALS

Cordova, Francis C., and Gerard J. Griner. "Management of Advanced Chronic Obstructive Pulmonary Disease." Comprehensive Therapy 23, no. 6: 413-424.

Lefrak, Stephen S., et al. "Recent Advances in Surgery for Emphysema." Annual Review of Medicine 48: 387-398.

ORGANIZATIONS

American Association for Respiratory Care. 11030 Ables Lane, Dallas, TX 75229. (214) 243-2272. 〈http://www.aarc.org〉.

American Lung Association. 1740 Broadway, New York, NY 10019. (800) 586-4872. 〈http://www.lungusa.org〉.

National Heart, Lung and Blood Institute. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. 〈http://www.nhlbi.nih.gov〉.

National Jewish Medical and Research Center. 1400 Jackson St., Denver, CO 80206. (800) 222-LUNG (Lung Line). 〈http://www.njc.org〉.

KEY TERMS

Alpha-1-antitrypsin (AAT)— A blood component that breaks down infection-fighting enzymes such as elastase.

Alveoli— Terminal air sacs of the respiratory system, where gas (oxygen and carbon dioxide) exchange occurs.

Bronchi— Large air tubes of the respiratory system.

Bronchioles— Small air tubes of the respiratory system.

Bronchodilators— Drugs that open wider the bronchial tubes of the respiratory system.

Corticosteroids— A group of hormones that are used as drugs to block inflammation.

Forced expiratory volume (FEV1)— The maximum amount of air expired in one second.

Spirometer— An instrument used by a doctor to perform a breathing test.

Vital capacity (VC)— The largest amount of air expelled after one's deepest inhalation.

Chronic obstructive pulmonary disease

Definition

Chronic obstructive pulmonary disease, or COPD, is difficulty breathing caused by obstruction of airflow in the lungs that is generally not reversible.

The two main diseases included in COPD are emphysema , which is enlargement and destruction of the air sacs of the lungs, and chronic bronchitis , or inflammation and eventual scarring of the airway tubes.

Description

The lungs serve the important function of breathing, exchanging oxygen that the body's organs need for carbon dioxide that gets taken out of the blood. This is called gas exchange and is performed well by healthy lungs. When air enters the nose and mouth, it travels through the windpipe, or trachea, to the bronchial tubes of the lungs. The larger tubes are called the bronchi and the smaller tubes are called bronchioles. At the ends of the bronchioles are small air sacs called alveoili. In healthy lungs, the alveoli and the bronchi are springy like elastic. Much like a balloon, the alveoli can fill up with air and deflate as air goes out. In people with COPD, the alveoli lose their shape and less air can get in or come out.

In addition, people with COPD may have clogged air passageways because of mucus because their cells make more mucus, or sputum, than usual. The increase in mucus makes people with COPD cough more. Those with COPD have trouble getting air into and out of their lungs. Both emphysema and chronic bronchitis develop over time and COPD is most common in people age 50 and older.

Demographics

More than 16 million people in the United States each year are affected by COPD. Millions more have evidence of impaired lung function, so COPD probably is underdiagnosed. The American Lung Association reported that in 2005, about 8.9 million Americans were diagnosed with chronic bronchitis. The highest rates of the disease were among those age 65 and older. After age 65, as many as 53 per 1,000 people may have chronic bronchitis. About 3.8 million Americans are diagnosed with emphysema and 91% of them are age 45 and older. The disease is a major reason for hospitalization among seniors, accounting for about 65% of hospital discharges amoung those age 65 and older in 2005.

COPD affects more smokers than nonsmokers. Women are twice as likely to be diagnosed with chronic bronchitis than men. The year 2005 marked five years in a row in which the number of women dying from COPD was higher than the number of men dying from the disease. COPD is the fourth leading cause of death in America.

Causes and symptoms

The damage to lungs that leads to COPD develops from repeated breathing in of irritants to the lungs and airways. Studies have proven absolutely that smoking cigarettes is the most common irritant that causes COPD and the highest risk factor for the disease. The number of packs smoked and number of years smoked vary somewhat in their effects on causing COPD among individuals. Smoking cigars or pipes also may cause COPD, but fewer tobacco byproducts are inhaled from cigar and tobacco smoke than from cigarette smoke.

Some people who work in occupations that expose them to certain dusts that might enter their lungs may be at higher risk for COPD. Coal mining, cotton textile manufacturing, and gold mining are among the occupations considered. But the effects of these occupational exposures are lower than the effects of cigarette smoke. Likewise, air pollution is much less important as a risk factor than cigarette smoking. Exposure of children to maternal smoking and passive smoke can have some effects. Respiratory infections have not been absolutely proven to cause COPD, though they can make COPD worse. In rare cases, COPD is caused by a genetic disorder called alpha 1 antitrypsin deficiency. In this disorder, an imbalance of a protein leads to the destruction of the lungs and eventual COPD. If people with the genetic disorder also smoke, they will develop COPD more quickly. Less than 5% of cases of COPD are caused by this genetic disorder.

The symptoms of COPD develop gradually, usually over years. The most common symptoms are cough, production of sputum, and shortness of breath, especially with exercise . People with COPD also may experience wheezing and tightness in the chest. Not everyone who has a persistent cough has COPD. Likewise, not everyone with COPD coughs regularly. Many people with COPD are not diagnosed with the disease until symptoms have progressed.

As COPD progresses, some symptoms, such as shortness of breath on exertion, will worsen. The timing depends on the individual. For example, COPD symptoms will worsen faster if a person continues to smoke. Often, use of the upper arms is harder for people with COPD and as they reach the later stages of the disease, they may find they get short of breath just from performing regular activities of daily living, such as preparing coffee or bathing.

Diagnosis

Simply having a history of heavy smoking is not enough to diagnose COPD. A physician will consider the diagnosis if the typical symptoms are present and if the patient has a history of smoking or exposure to other lung irritants. Physicians will look at the patient's medical history and use a number of tests to arrive at the diagnosis. Most important to the medical history is information about cigarette smoking or smoking of other tobacco products, as well as how much was smoked and for how long. The physician will examine the patient for signs that show the patient has trouble breathing, such as skipped breaths, use of muscles around the chest to help with difficult breathing, or pursed-lip breathing. Signs of wheezing and chronic mild cough also may be present. The patient may have a harder time breathing while laying down, have fatigue, insomnia , or morning headaches .

The physician may use breathing tests to determine pulmonary function. Spirometry is an easy, painless test that helps tell how the lungs are working. The patients breathes hard into a hose that connects to a machine called a spirometer. The machine measures how much air the lungs can hold and how quickly the person can blow air out of the lungs after taking a deep breath. The physician will use the measurements of volume of air the patient can forcefully blow out (referred to as forced vital capacity and forced expiratory volume), along with other symptoms to determine if the patient is at risk for COPD or how severe the disease may be. For example, a person with chronic cough and sputum production but normal sprimotetry results is simply at risk for COPD. With mild COPD, the test shows mild airflow limitation and the patient may not be aware that airflow in the lungs is reduced. With moderate COPD, the breathing test shows that airflow limitation is worsening. The patient may have noticed that shortness of breath has worsened, particularly when walking fast or doing physical activity. Patients with severe or very severe COPD will have low percentage ratios of volume readings. Those with very severe COPD also will become short of breath after light physical activity and may show signs of right heart failure. They may or may not have chronic cough and sputum production.

Other breathing tests used to diagnose COPD include diffusion studies, which determine how well oxygen in the air moves from the lungs into the blood. A blood sample may be taken to determine arterial blood gas. This can measure the amount of oxygen and carbon dioxide in the blood to see if these gases are being exchanged correctly. Chest x-rays traditionally have been used to look for signs that suggest emphysema. Patients in early stages of the disease may show no signs, but as the disease progresses, a radiologist can note excessive inflation of the lungs and an abnormally increased chest diameter. In recent years, computed tomography (CT) scans have become the favored test to diagnose presence of emphysema.

Treatment

Only two treatments have been found to help people with COPD breathe more easily. Quitting smoking helps ease symptoms and slow the progress of the disease. Oxygen therapy helps patients with severe disease to receive enough oxygen.

Treatment for COPD is based on relieving symptoms, preventing complications, and improving a patient's overall health. The treatment varies depending on a patient's symptoms and stage of COPD. Treatment also may change over time and if a patient experiences complications or sudden onset of more severe symptoms.

Physicians will urge all patients with COPD who smoke to quit smoking. Quitting will not reverses the COPD, but will make the decline in lung function slower. Physicians may prescribe special gum, patches, inhalers, or nose sprays to replace nicotine as patients learn how to quit smoking. Bronchodilators , the inhalers often used by people with asthma , may be used to relieve the symptoms of people with COPD and help them breathe more easily as needed throughout the day. Bronchodilators also may have medicines called anticholinergics, inhaled medicines that don't act as quickly as the beta2-agonists in asthma inhalers, but that last longer. Inhaled steroids may be used for a short time to treat people with moderate to severe COPD to reduce inflammation in the airways.

Supplemental oxygen is the only therapy that has been demonstrated to reduce the number of deaths in patients with COPD. The treatment usually is reserved for patients who are not getting enough oxygen on their own. The oxygen may be delivered by a portable tank that allows the patient to be mobile outside the home, through a concentrator unit placed in the home, or through some combination. Some patients will receive oxygen some of the time, such as when short of breath. Others may receive it only at night. Using extra oxygen more than 15 hours a day helps people perform activities with less shortness of breath, remain more alert during the day, and protects the heart and other organs from damage.

QUESTIONS TO ASK YOUR DOCTOR

• How can I improve my breathing throughout the day?
• What steps can I take now to slow progress of the disease?
• What sorts of signs or symptoms should I watch for that indicate a more serious problem?

Some people with COPD may be candidates for surgery. Usually, this is only used for patients who have severe symptoms and have not improved with medications. A transplant of both lungs may be used, but generally only for certain patients, particularly younger patients.

Nutrition/Dietetic concerns

People with COPD may have more trouble breathing if they eat large meals because the stomach pushes on the diaphragm, the muscle that helps in breathing. Seniors with COPD also need to eat well-balanced diets because good nutrition helps fight infection. In the more severe stages of COPD, patients can experience loss of weight and decreased muscle tissue, so these patients may need to eat high-calorie foods. Most people with COPD are encouraged to drink extra fluids to keep mucus thin and easier to cough up. Some have heart conditions that require less fluid. If a patient has a cannula through which oxygen is provided, it should be left in place while eating.

Therapy

People with COPD may have pulmonary rehabilitation , a program that includes exercise instruction and counseling to help patients stay more active and able to perform daily activities. Physicians, nurses, physical therapists, dietitians, and respiratory therapists may help with this therapy.

Prognosis

COPD is a serious and chronic disease that cannot be reversed. If detected early, the effects and progression of COPD can be slowed, especially if the patient stops smoking immediately. Patients with COPD can work to improve their breathing and reduce chance of symptom flare-ups to improve their quality of life and how long they will live with COPD. Staying healthy and out of the hospital helps reduce mortality.

Prevention

The best way to prevent COPD is to avoid cigarette smoking. Even people with genetic disorders linked to COPD are more likely to develop the disease if they smoke. Seniors with COPD can help prevent complications and progression of the disease by receiving vaccines for flu shots and pneumonia .

Caregiver concerns

Care givers, whether they live with the senior with COPD or not, can help ensure the person has all necessary medications. Care givers can try to make it easier for the senior to perform daily activities if breathing becomes more difficult, but also try to encourage light exercise as prescribed. Both the senior and care givers should know the signs to watch for that indicate a physician should be called. Eventually, most people with advanced COPD will reach a point where they will need the help of a care giver to even manage daily activities.

KEY TERMS

Bronchodilator —These medications can expand the lungs' capacity for a short time; they often are used for people with asthma and are referred to as “inhalers.”

Pulmonary —Related to or carried on by the lungs.

Sputum —The matter that is discharged from the lungs when they are diseased. It usually contains mucus and may contain other substances such as blood or pus.

Resources

BOOKS

Reilly, John J., Edwin K. Silverman, and Steven D. Shapiro. “Chronic Obstructive Pulmonary Disease.” In Harrison's Internal Medicine. New York: The McGraw-Hill Companies 2005.

PERIODICALS

Parmet, S. “Chronic Obstructive Pulmonary Disease.”JAMA (November 5, 2003): 2362.

OTHER

Living With Advanced Lung Disease: A Guide for Family Caregivers. The Washington Center for Palliative Care Studies, a Division of the Rand Corporation, 2002. http://www.medicaring.org/educare/download/corpdbookfinal.pdf.

ORGANIZATIONS

American Lung Association, 61 Broadway, 6th Floor., New York, NY, 10006, (800) 548-8252, (212) 315-8700, www.lungusa.org.

National Heart, Lung, and Blood Institute, P.O. Box 30105, Bethesda, MD, 20824-0105, (301) 592-8573, (240) 629-3246, [email protected], www.nhlbi.nih.gov.

Teresa G. Odle

Chronic Obstructive Pulmonary Disease

Definition

Chronic obstructive pulmonary disease (COPD) is a gradually progressive and permanent disease of the airways and lungs that is described as a slow loss of lung function. As of 2000, COPD was reported by the National Center for Environmental Health to be one of the leading causes of death, illness, and disability in the United States. As of 2003, it was reported by the National Heart, Lung, and Blood Institute (NHLBI) to be the fourth leading cause of death in the United States. However, leaders of the NHLBI predict that COPD will become the third leading cause of death in the United States by the year 2020. In adults who are 25 years of age and older, about 12.1 million people have been diagnosed with COPD in 2001, although it is estimated that approximately 24 million Americans could have COPD without any knowledge. At the same time, around 1.5 million hospital emergency department visits, 726,000 hospitalizations, and 119,000 deaths have occurred because of COPD.

A greater number of females are reported with COPD than men, along with a greater number of whites over blacks. However, when statistics are adjusted with respect to age, the death rate is about 46 percent higher in males than females and about 63 percent higher in whites than blacks. Cigarette smoking is the most common cause of COPD but the inhalation of chemicals, dust, or pollutions over a long period of time can also contribute to the disease.

Description

The disease of COPD includes such conditions as chronic obstructive bronchitis (emphysema), chronic bronchitis, a mixture of the two, and in some cases asthma. In healthy people, the airways of the lungs remain open and clear, and flexible and strong. They easily inflate and deflate. However, when the lung's airways are subjected to irritants such as smoke and chemicals they lose their elasticity and strength over an extended period. At the same time, cells in the airways produce more sputum (mucus) due to the constant, irritated state of the lungs, which makes it increasingly difficult for the airways to remain open and clear. COPD is developing very slowly. likely over many years, as these harmful changes take place. Eventually the walls of the airways are destroyed. Once COPD develops it is irreversible (that is, permanent) because the damage done to the lungs, airways, and walls of the airways cannot be repaired by the body.

Causes and symptoms

The primary cause of COPD in the United States is cigarette smoking along with the smoking of pipes and cigars. Secondary (passive) exposure to cigarette smoke is also a contributing factor to COPD. Occupational chemicals, dusts, and airborne particulates in the workplace have also been documented to be factors that can lead to the disease, as have air pollutants in the home. Outdoor air pollution has not been documented to be a significant factor to COPD, although such pollution is never good to anyone who is at risk for developing COPD. Genetic and hereditary factors are also a consideration in causing COPD, as are persistent respiratory infections and asthma.

The symptoms of COPD range from chronic cough and sputum production to severe shortness of breath. When a person first is diagnosed with a persistent cough and sputum production, it is usually a good indication that the person may be at risk for later developing symptoms of airflow obstruction and disabling shortness of breath. However, in some individuals, little cough and sputum production is apparent when they are first diagnosed with shortness of breath, which is normally the first indication of COPD. Weather conditions can temporarily make the symptoms worse, as can infections to the body unrelated to the disease.

Diagnosis

The diagnosis of COPD involves determining the presence of airway obstructions when testing with a spirometer in a process known as spirometry. Currently, there is no known cure for COPD. Since about 24 million adults are annually diagnosed with impaired lung functions (and only 12.1 million adults are diagnosed with COPD each year), the disease is considered under-diagnosed by the medical community.

Treatment

Early detection of COPD may help to slow the progress of the disease. A test that measures pulmonary function has been shown to diagnose accurately COPD in current and former tobacco smokers (who are over 45 years of age) and others with continuing respiratory problems. A physician will make a complete evaluation of anyone suspected of having COPD. Coughing and wheezing symptoms will be treated with medication. Respiratory infections will be treated with antibiotics. Persons who cannot obtain enough oxygen through their lungs will be provided oxygen through tanks. However, since no cure is known, health care personnel at COPD treatment centers rely mostly on relieving the symptoms and making the patient as comfortable as possible.

Prognosis

If a person fails to discontinue exposure to smoke, especially tobacco products and other noxious particles, the disease will eventually restrict the person's airways and the ability to breathe will be lost. In 2000, according to the National Heart, Lung, and Blood Institute, about 119,000 people died from COPD. According to the Centers for Disease Control and Prevention, the number of deaths increased to nearly 125,000 in 2002.

Health care team roles

The health care team is are often called to perform emergency procedures on people with COPD. About 1.5 million emergency room visits were made annually at the beginning of the twenty-first century expressly for the treatment of COPD. In addition, about 726,000 people are hospitalized annually for COPD, especially at times when the disease is exacerbated by such external factors as adverse weather conditions (such as smog) and illnesses (such as acute infections). Medical teams work with various state, federal, and world organizations to combat the disease. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) is especially well-known (since its origins in 1997) for its international work with health care professionals and public health providers in seeking a cure for COPD, along with raising awareness of the disease. In the United States, the U.S. COPD Coalition also works to improve the lives of people with the disease.

Prevention

The best way to prevent COPD is the avoidance of smoke of any kind but especially the smoke contained within tobacco products since it has been shown to be the leading cause of COPD.

KEY TERMS

Asthma— A respiratory disease associated with coughing and wheezing, sudden difficulty in breathing, and a tightening in the chest.

Pulmonary— Relating to the lungs.

Spirometry— A test for measuring lung capacity especially concerning the speed and volume of air in the passageway.

Sputum— Coughed-up substances through the throat; often called mucous or phlegm.

Resources

BOOKS

Garrod, Rachel, ed. Pulmonary Rehabilitation: An Interdisciplinary Approach. London, U.K., and Philadelphia: Whurr, 2005.

OTHER

Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD). "Homepage for GOLD" 〈http://www.goldcopd.com/〉 (accessed October 25, 2005).

National Center for Environmental Health, Centers for Disease Control and Prevention. "Facts About Chronic Obstructive Pulmonary Disease (COPD)" 〈http://www.cdc.gov/nceh/airpollution/copd/copdfaq.htm〉 (accessed October 25, 2005).

National Center for Health Statistics, Centers for Disease Control and Prevention. "Chronic Obstructive Pulmonary Disease (COPD)" 〈http://www.cdc.gov/nchs/fastats/copd.htm〉 (accessed October 26, 2005).

National Center for Health Statistics, U.S. COPD Coalition. "Homepage for U.S. COPD Coalition" 〈http://www.uscopd.com/〉 (accessed October 25, 2005).

National Heart, Lung, and Blood Institute; National Institutes of Health; U.S. Department of Health and Human Services. "Chronic Obstructive Pulmonary Disease" 〈http://www.nhlbi.nih.gov/health/public/lung/other/copd_fact.pdf〉 (accessed October 24, 2005).

chronic obstructive pulmonary disease (COPD, chronic obstructive airways disease, COAD) n. a disease of adults, especially those over the age of 45 with a history of smoking or inhalation of airborne pollution. It has features of emphysema and chronic bronchitis and is diagnosed, according to the GOLD guidelines, at different stages (0–4) based on the value of the forced expiratory volume in 1 second (FEV₁). Different treatment regimens are recommended for different stages: inhaled corticosteroids and long-acting beta agonists can improve quality of life and survival in the later stages.