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What is COPD?

A Comprehensive Guide to Chronic Obstructive Pulmonary Disease (COPD)

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Updated April 09, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Chronic Obstructive Pulmonary Disease (COPD)

Smoking: The #1 Cause

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COPD

COPD and Your Lungs

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Air Pollution and COPD

Air Pollution: A Common Cause of COPD

Photo © istockphoto.com user Aaliya Landholt

COPD stands for chronic obstructive pulmonary disease. Although incurable, it is a preventable and treatable illness that not only affects the lungs, but other parts of the body, as well. These "extrapulmonary effects" as they are referred to by medical experts, are thought to contribute to the severity of COPD in people who are diagnosed with the disease.

The Characteristics of COPD

COPD is characterized by limitation of airflow - both into and out of the lungs - that is not fully reversible. This means less air flows in and out of your lungs because of one or more of the following factors:

  • The air tubes and alveoli (air sacs where gas exchange take place) lose their elasticity and are unable to stretch when you breathe.
  • The walls that lie between the alveoli get destroyed.
  • The lining of the the air tubes becomes thick and inflamed.
  • The air tubes secrete more mucus than they should, causing them to clog.

Airflow limitation in COPD is progressive, meaning it generally worsens over time. It is associated with an abnormal inflammatory response of the lungs to noxious stimuli, like cigarette smoke, air pollution or harsh chemicals.

Statistics

COPD is the third-leading cause of death in the United States, preceded by only heart disease and cancer. It kills over 126,000 Americans annually. Historically, COPD has occurred more frequently in men; however, since 2000, more women have died each year from the disease than men. To date, COPD remains a growing healthcare concern for women in many countries. See COPD in Women.

COPD predominantly occurs in people over 40 years of age. According to the Centers for Disease Control and Prevention, 15 million Americans have been diagnosed with COPD as of 2011. However, approximately 24 million U.S. adults have evidence of impaired lung function, indicating that there is a high probability of under-diagnosis.

Types of COPD

COPD is a term that is often used to describe a group of lung diseases including:

Quite often, people with COPD have a combination of these disorders at the same time. It's also possible to have an asthma component with the disease, important factors when considering treatment.

It should be noted that the definition of COPD, stemming from the Global Initiative for Obstructive Lung Disease (GOLD), no longer includes the terms "emphysema" and "chronic bronchitis". The following explains the rationale for this:

Many previous definitions of COPD emphasized the terms "emphysema" and "chronic bronchitis" which are not included in the definition used in this, or earlier GOLD reports. Emphysema, or destruction of the gas-exchanging surfaces of the lung (alveoli), is a pathological term that is often (but incorrectly) used clinically and describes only one of several structural abnormalities present in patients with COPD. Chronic bronchitis, or the presence of a cough and sputum production for at least 3 months in each of 2 consecutive years remains a clinically and epidemiologically useful term. However, it is important to recognize that chronic cough and sputum production (chronic bronchitis) is an independent disease entity that may precede or follow airflow limitation and may be associated with development and/or acceleration of fixed airflow limitation. Chronic bronchitis also exists in patients with normal spirometry."

COPD Pathophysiology

According to the American Academy of Family Physicians, what happens physiologically to your lungs when you have COPD is not completely understood. Playing a major role is that of chronic inflammation in the cells that line the bronchial tree in the lungs. Smoking and other airway irritants perpetuate an ongoing inflammatory response that leads to hyperactivity of the airways, whereby the smooth muscle of the airways constrict and narrow excessively. This causes the airways to become swollen, excess mucus to be produced and the cilia to function poorly.

As the disease progresses, many patients find it increasing difficulty to clear their secretions, developing a chronic, productive cough, wheezing and dyspnea, the hallmark symptoms of COPD. Once the lungs start producing too much mucus, it begins to pool in the airways, providing a perfect breeding ground for bacteria to multiply. This leads to even more inflammation, the formation of diverticuli (pouch-like sacs) in the bronchial tree and frequent bacterial infections so common among COPD patients.

Risk Factors

The most significant risk factor for COPD is cigarette smoking. The American Lung Association estimates that 80% to 90% of people diagnosed are either chronic or former smokers; however, never-smokers also get COPD (read COPD in the Never-Smoker.)

Other common risk factors include:

For a complete list of risk factors, read Are You at Risk for COPD? Also, to assess your own risk for the disease, check out this COPD Risk Self-Assessment Questionnaire.

Alpha-1-Antitrypsin Deficiency

Alpha-1-antitrypsin (AAT) deficiency is a genetic disorder that can lead to emphysema and/or liver disease. It is relatively rare, occurring in a very small number of patients. It is genetic because it is passed on by one or both parents at birth.

The onset of symptoms in people with AAT deficiency emphysema typically occurs between the ages of 32 and 41, much earlier than in COPD which is not caused by AAT deficiency. If you fall within this age group and have been diagnosed with emphysema, ask your doctor for a simple blood test to determine if your COPD is caused by AAT deficiency, as treatment options differ from standard COPD treatment.

Symptoms

Hallmark symptoms of COPD include:

Additional signs and symptoms that may accompany the more severe stages of the disease include weight loss, anorexia, and fatigue.  Ankle swelling may occur as a result of medication side effects or co-existing heart problems. Anxiety and depression are common emotional symptoms of COPD for which additional treatment may be necessary to improve quality of life and lower the risk of COPD exacerbation.

Diagnostic Testing

To make an accurate diagnosis of chronic obstructive pulmonary disease, a complete history and physical assessment must be taken that should start with your health care provider asking you questions about your family history, as well as your history of exposure to tobacco smoke and other types of environmental and/or occupational exposures. Additional diagnostic tests may include:

Treatment

The best treatment for the disease if you are a smoker is to quit as soon as possible. Other treatment options include:

Preventative Tips

Although the disease is treatable, it must be emphasized that once you have COPD, the damage is irreversible and there is no known cure. However, it is important to take whatever steps you can to prevent the damage from worsening.

If you don't already have the disease, the following steps can help you prevent it from occurring:

  • If you smoke, you should quit ASAP!
  • If you live with someone who smokes, make sure they do not smoke around you. Additionally, no one should ever smoke when a child is present. Learn more about the dangers of secondhand smoke.
  • If you work around hazardous chemicals, dust or other types of occupational hazards that may irritate your lungs, be sure to wear protective equipment including a mask and gloves.
  • If you are at risk for developing the disease as determined by your doctor, get a yearly flu shot.
  • Learn how to improve the air quality in your home.
  • Obtain a spirometry test to improve your chances of early detection.

If, after reading this article, you're still asking the question "What is COPD?" Compare Prices on COPD for Dummies and get more information about causes, symptoms, diagnosis and treatment of COPD.

Sources:

The Global Initiative for Obstructive Lung Disease. Global Strategy for the Diagnosis, Management and Prevention of Chronic Obstructive Pulmonary Disease. Updated 2014.

The National Heart, Lung and Blood Institute. What is COPD? Updated June 8, 2012.

Taylor, Jill. "Underdiagnosis of COPD Observed in General Practice." Medscape Medical News, 2004.

COPD Fact Sheet. (2007). American Lung Association.

U.S. Department of Health and Human Services. Centers for Disease Control and Prevention. Behavioral Risk Factor Surveillance System, 2011.

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