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