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Chronic obstructive pulmonary disease (COPD) is also called chronic obstructive lung disease. When we think of diseases that obstruct the lungs, many people may think of asthma. (Read about "Asthma") But the National Heart, Lung, and Blood Institute (NHLBI) says COPD specifically refers to two other respiratory diseases: chronic bronchitis and emphysema. These two diseases often, though not always, appear together in the same patient.
Risk factors include:
COPD is often progressive. It may start with shortness of breath and coughing. Then a chronic cough can develop, which can be accompanied by clear sputum. Later the cough often becomes more frequent and it's harder to get air into the lungs. Airways become obstructed. People with COPD may be at higher risk of pneumothorax, a condition that can lead to collapsed lung. (Read about "Pneumothorax") The National Emphysema Foundation says carbon dioxide can build up in the blood and blood oxygen levels diminish. Eventually the heart may be affected and the disease can be fatal if the lungs and heart can no longer deliver oxygen to the body's organs and tissues. (Read about "The Heart & Cardiovascular System" "Coronary Heart Disease" "Congestive Heart Failure")
NHLBI says an estimated 12 million Americans are diagnosed with COPD. Many more are unaware they have COPD. It usually develops in older people, and is more common in men than women. Chronic bronchitis affects over 14 million people in the United States, according to the American Lung Association (ALA). ALA says chronic bronchitis affects people of all ages, but is higher in those over 45 years old. Chronic bronchitis is also more common in women, than men.
In emphysema, there is permanent destruction of the alveoli or tiny elastic air sacs of the lung. There is also narrowing of the smallest air passages of the lungs or bronchioles, which restricts airflow from the lungs.
What causes this to happen? NHLBI says there is a protein in the lungs called elastin that normally helps to maintain the strength of the alveolar walls. But in emphysema, this protein gets destroyed.
NHLBI says this can happen when there is a deficiency of an enzyme called alpha-l-protease inhibitor or alpha-l-antitrypsin (AAT), which normally protects the elastin. For example, people with familial emphysema have a hereditary deficiency of AAT. ALA says an estimated 50,000-100,000 Americans living today were born with this deficiency. According to NHLBI, 1 to 3 percent of all cases of emphysema are due to AAT deficiency.
The majority of cases of emphysema are not genetic, however. In the general population, the National Emphysema Foundation says emphysema usually develops in older individuals with a long smoking history. NHLBI says this far more common form of emphysema may also be the result of an imbalance between elastin-degrading enzymes (called elastase) and their inhibitors, and that this imbalance may actually be caused by smoking. On the other hand, NHLBI says that only 15 to 20 percent of smokers develop emphysema, so there must be other factors at play too. However, if someone has a family history (Read about "Family Health History") of emphysema, a blood test can determine if they have a genetic AAT deficiency (Read about "Laboratory Testing") and if so, the National Emphysema Foundation says it would be critical for these people not to smoke.
The first and most noticeable symptom of emphysema is shortness of breath. There can also be coughing. During a physical exam, a doctor may listen to the chest with a stethoscope and listen to the heart to see if there are any signs of heart strain that may accompany advanced stages of emphysema.
Other tests include spirometry, in which a tube is connected to a machine, and the patient takes a deep breath and blows it out as quickly as possible, while the machine measures his or her airflow capacity. In addition, blood may be tested to determine the amounts of carbon dioxide and oxygen. A chest x-ray or computerized axial tomography (CAT) scan can be used in advanced cases. (Read about "X-rays" "CT Scan - Computerized Tomography")
See treatment options and prevention below.
Chronic bronchitis is the other major lung disease grouped under COPD. The American Academy of Family Physicians (AAFP) says it is basically an inflammation of the lining of the bronchial tubes that connect the windpipe with the lungs. As a result, airflow to and from the lungs is restricted and a heavy mucus or phlegm is coughed up. Chronic bronchitis may also involve a narrowing of the large and small airways making it more difficult to move air in and out of the lungs.
You may have had a brief attack of acute bronchitis if you had a bad cold. In chronic bronchitis, however, the mucus-producing cough doesn't go away; instead, it occurs most days of the month. NHLBI says someone is considered to have chronic bronchitis if cough and sputum are present on most days for a minimum of 3 months for at least 2 successive years or for 6 months during a single year.
ALA says cigarette smoking is the most common cause of chronic bronchitis. In addition, the bronchial tubes of people with chronic bronchitis may also have been irritated initially by a number of other substances including:
The number of irritants someone is exposed to can add up and create a heightened effect. For example, ALA says coal miners, grain handlers, metal molders and other workers exposed to dust are particularly at risk, and if someone in this type of work is also exposed to heavy air pollution or smoke, their symptoms can get even worse. (Read about "Occupational Respiratory Diseases") In addition, once the bronchial tubes have been irritated over a long period of time, they can become even more susceptible to infections.
See treatment options and prevention below.
One of the potential consequences of COPD is pulmonary hypertension (PH). Pulmonary hypertension happens when the blood pressure in the pulmonary artery rises far above normal levels. (Read about "Pulmonary Hypertension")
Survival of patients with COPD is closely related to the level of their lung function when they are diagnosed and the rate at which they lose this function. Patients with severe lung damage may need to sleep in a semi-sitting position because they can't breathe when they lie down. They may need to breathe oxygen. Breathing oxygen can often correct the blood oxygen levels, but this does not help remove carbon dioxide. When carbon dioxide accumulation becomes a severe problem, mechanical breathing machines called respirators, or ventilators, must be used.
If caught and treated early on, however, a patient can reduce the amount of damage that occurs. A doctor will decide on the best course of treatment, depending on the type and severity of the patient's condition. But it's essential that the patient follow their treatment program carefully.
For someone with emphysema, the Food and Drug Administration (FDA) says there are a number of treatments that can help, but the most important step is to stop smoking. It's also essential to avoid exposure to other airborne irritants besides smoke. For some patients, supplemental inhaled oxygen may provide some relief. Beyond that, FDA says medications can include:
In some cases, surgery may be needed to improve a patient's breathing ability. Again, a patient should discuss all options with their doctor, as well as their best course of action with regards to physical activity and special breathing exercises.
For someone with bronchitis, ALA says it's essential to reduce the irritation in the bronchial tubes. A patient with bronchitis should see their doctor at the first sign of a cold or respiratory infection. Antibiotics may be used if there is an infection. (Read about "Antibiotics") Bronchodilator drugs may be prescribed to help relax and open up air passages in the lungs, if there is a tendency for these to close up. There are also drugs that can treat the symptoms of cough and excess mucus linked to bronchitis. A patient should avoid polluted air and dusty working conditions, maybe even change jobs if necessary.
ALA says people with bronchitis, emphysema or both should also follow a healthy diet and maintain a healthy body weight. (Read about "Body Mass Index") They should talk with their doctor about getting vaccinated against flu or pneumonia. (Read about "Influenza" "Pneumonia") AAFP says they should ask their doctor about an exercise program called pulmonary rehabilitation that can help improve breathing. (Read about "Rehabilitation") Above all, people with chronic bronchitis and/or emphysema who smoke should stop smoking and should avoid exposure to all secondary smoke. (Read about "Quit Smoking")
The hopeful news, according to NHLBI, is that many patients with COPD have some degree of reversible airways obstruction. And although there is no cure for COPD, the disabling symptoms can often be reduced. Above all, keep in mind that the disease can be prevented in many cases. Because cigarette smoking is the most important cause of COPD, NIH says not smoking almost always prevents COPD from developing, and quitting smoking slows the disease's progression.
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