COPD, or chronic obstructive pulmonary disease, is a long-term lung disease that refers to both chronic bronchitis and emphysema.

COPD is most often caused by smoking. Most people with COPD are long-term smokers, and research shows that smoking cigarettes increases the risk of getting COPD:

●Out of every 100 long-term smokers, about 15 to 20 get COPD with symptoms. That means that about 80 to 85 out of 100 do not get COPD with symptoms.

●Some studies show that up to half of long-term smokers older than age 60 get COPD.

●Smoking both tobacco and marijuana increases the risk of COPD more than smoking either one.

COPD is often a mix of two diseases: chronic bronchitis and emphysema. Both of these diseases are caused by smoking. Although you can have either chronic bronchitis or emphysema, people more often have a mixture of both diseases.

Almost all people with chronic bronchitis are, or have been, tobacco smokers. Over time, tobacco smoke and other lung irritants can lead to inflammation in the airways of the lungs (bronchial tubes). As a result, the airways produce more mucus than they normally would. Inflammation and excess mucus cause coughing and narrow the airways. It is hard to breathe through the narrow airways, so you feel short of breath.

Long-term (chronic) mucus production and inflammation over many years may lead to permanent lung damage and may make it more likely that you will get lung infections.

In emphysema, tobacco smoke and other irritants can damage the elastic fibers in the lungs. These stretchy strands of tissue are needed for normal lung function. They allow the lung tissue to stretch when you breathe in and help pull the lungs back to their normal size and shape as you breathe out. When the elastic fibers are damaged:

●The tiny air sacs (alveoli) at the end of the bronchial tubes are damaged. These air sacs are where the blood exchanges carbon dioxide (a by-product of metabolism) for oxygen. When air sacs are damaged or destroyed, their walls break down and the sacs become larger. These large air sacs move less oxygen into the blood. After air sacs are destroyed, they cannot be replaced.

●The smaller airways in the lungs (bronchioles) tend to collapse when you breathe out, trapping air in the alveoli. As a result, oxygen-rich air has trouble entering the air sacs. And carbon dioxide has a harder time getting out of the lungs.

See pictures of bronchitis and emphysema.

In chronic bronchitis, exposure to tobacco smoke and other lung irritants over time can lead to inflammation in the airways that deliver air into the lungs (bronchial tubes). As a result, the airways produce more mucus than they would normally. Inflammation and extra mucus reduce air flow and cause coughing. Mucus production and inflammation over many years may lead to progressive and permanent lung damage.

Emphysema is a long-term (chronic) lung disease. In emphysema, the tiny air sacs (alveoli) at the end of the airways in the lungs are damaged. When the air sacs are damaged or destroyed, their walls break down and the sacs become larger. These larger air sacs move less oxygen into the blood. This causes difficulty breathing or shortness of breath that gets worse over time. After air sacs are destroyed, they cannot be replaced.

Emphysema is a form of chronic obstructive pulmonary disease (COPD). It is usually caused by smoking. A rare type of emphysema is caused by the lack of a substance in the lungs called alpha1-antitrypsin. This type of emphysema is usually inherited.

Other possible causes of COPD include:

●Long-term exposure to lung irritants such as industrial dust and chemical fumes.

●Preterm birth that leads to lung damage (neonatal chronic lung disease).

●Inherited factors (genes), including alpha-1 antitrypsin deficiency, a rare condition in which your body may not be able to make enough of a protein (alpha-1 antitrypsin) that helps protect the lungs from damage. People who have this disorder and who smoke generally start to have symptoms of emphysema in their 30s or 40s. Those who have this disorder but do not smoke generally start to have symptoms in their 80s.

When you have COPD:

●You have a cough that won't go away.

●You often cough up mucus.

●You are often short of breath, especially when you exercise.

Many people with COPD have attacks called flare-ups or exacerbations (say “egg-ZASS-er-BAY-shuns”). This is when your usual symptoms quickly get worse and stay worse. A COPD flare-up can be dangerous, and you may have to go to the hospital.

Symptoms include:

●Coughing up more mucus than usual.

●A change in the color or thickness of that mucus.

●More shortness of breath than usual.

These attacks are most often caused by infections-such as acute bronchitis and pneumonia-and air pollution.

Work with your doctor to make a plan for dealing with a COPD flare-up. If you are prepared, you may be able to get it under control. Try not to panic if you start to have one. Quick treatment at home may help you manage serious breathing problems.

The stages of COPD are often defined according to your symptoms plus a measure of how well your lungs work, called your “lung function”.

In the following symptoms lists, lung function FEV1 is a test result that shows how fast you can breathe air out of your lungs. FEV1 stands for forced expiratory volume in 1 second.

FEV1 can be measured by machines called spirometers. The test result is reported as a percentage of normal. In other words, an FEV1 of 100% means the lungs are working normally; 80% is less than normal; 30% is very much less than normal.

Here is how the stages of COPD are described by the Global Initiative for Chronic Obstructive Lung Disease.

●Mild COPD (stage 1)

Usually, but not always, a chronic cough that often brings up mucus from the lungs

Lung function FEV1 of 80% of normal or higher

●Moderate COPD (stage 2)

Chronic cough with a lot of mucus

Shortness of breath, especially with exercise

An occasional COPD flare-up

Lung function FEV1 of 50% to 79%

●Severe COPD (stage 3)

Chronic cough with a lot of mucus

Shortness of breath

Fatigue and a reduced ability to exercise

Repeated and sometimes severe COPD flare-ups

Lung function FEV1 of 30% to 49%

●Very severe COPD (stage 4)

Chronic cough with a lot of mucus

Severe shortness of breath

Weight loss

Blue skin color, especially in the lips, fingers, and toes (called cyanosis)

Fluid buildup in the legs and feet (called edema)

Life-threatening COPD flare-ups

Lung function FEV1 of less than 30%, or of less than 50% along with chronic respiratory failure (a condition caused by carbon dioxide that stays in the lungs)

Conditions with symptoms similar to COPD include:

●Heart failure.

●Coronary artery disease.

●Asthma. Some people with COPD may have asthma too. But the two conditions differ in a number of ways, including how old you are when you get the disease and what triggers an attack.

●Cystic fibrosis.

●Pulmonary fibrosis.

●Bronchiectasis.

To diagnose COPD, do the following tests:

●Medical history and physical exam. These will give your doctor important information about your health.

●Lung function tests. These measure the amount of air in your lungs and the speed at which air moves in and out. Spirometry is the most important of these tests.

●Chest X-ray. This helps rule out other conditions with similar symptoms, such as lung cancer.

●Arterial blood gas test. This test measures how much oxygen, carbon dioxide, and acid is in your blood. It helps your doctor decide whether you need oxygen treatment.

●Oximetry. This test measures the oxygen saturation in the blood. It can be useful in finding out whether oxygen treatment is needed, but it provides less information than the arterial blood gas test.

●Electrocardiogram (ECG, EKG) or echocardiogram. These tests may find certain heart problems that can cause shortness of breath.

●Transfer factor for carbon monoxide. This test looks at whether your lungs have been damaged, and if so, how much damage there is and how bad your COPD might be.

●A test to measure levels of alpha-1 antitrypsin, or ATT. ATT is a protein your body makes that helps protect the lungs. People whose bodies don't make enough ATT are more likely to get emphysema.

●A CT scan. This gives doctors a detailed picture of the lungs.

Because COPD is a disease that keeps getting worse, it is important to schedule regular checkups with your doctor. Checkups may include:

●Spirometry.

●Arterial blood gas test.

●X-rays or ECGs.

Tell your doctor about any changes in your symptoms and whether you have had any flare-ups. Your doctor may change your medicines based on your symptoms.

The sooner COPD is diagnosed, the sooner you can take steps to slow down the disease and keep your quality of life for as long as possible. Screening tests help your doctor diagnose COPD early, before you have any symptoms.

Talk to your doctor about COPD screening if you:

●Are a smoker or ex-smoker.

●Have had serious asthma symptoms for a long time, which have not improved with treatment.

●Have a family history of emphysema.

●Have a job where you are exposed to a lot of chemicals or dust.

The U.S. Preventive Services Task Force (USPSTF) does not recommend COPD screening for adults who are not at high risk of developing COPD.

Although COPD cannot be cured, it can be managed. The goals of treatment are to:

●Slow down the disease by avoiding tobacco smoke and air pollution.

●Limit your symptoms, such as shortness of breath.

●Increase your activity level.

●Improve your overall health.

●Prevent and treat flare-ups. A flare-up, or exacerbation, is when your symptoms quickly get worse and stay worse.

Many people are able to manage their COPD well enough to take part in their usual daily activities, hobbies, and family events.

At first, treatment for COPD helps you breathe better and slow the disease. Much of the treatment includes things you do for yourself:

●Quit smoking. This is so important. And it's never too late. No matter how long you have had COPD or how serious it is, quitting smoking will help slow down the disease and improve your quality of life. Today's medicines offer lots of help for people who want to quit. You will double your chances of quitting even if medicine is the only treatment you use to quit, but your odds get even better when you combine medicine and other quit strategies, such as counseling.

●Stay active. If you stay active, you may have less shortness of breath, have a better attitude about your life and the disease, and be less likely to feel depressed or isolated from friends and family. Exercise improves shortness of breath and will help you be more active.

Medicine for COPD is used to:

●Reduce shortness of breath.

●Control coughing and wheezing.

●Prevent COPD flare-ups, also called exacerbations, or keep the flare-ups you do have from being life-threatening.

Most people with COPD find that medicines make breathing easier.

Some COPD medicines are used with devices called inhalers or nebulizers. Most doctors recommend using spacers with inhalers. It's important to learn how to use these devices correctly. Many people don't, so they don't get the full benefit from the medicine.

Lung surgery is rarely used to treat COPD. Surgery is never the first treatment choice and is only considered for people who have severe COPD that has not improved with other treatment.

●Lung volume reduction surgery: Removes part of one or both lungs, making room for the rest of the lung to work better. It is used only for severe emphysema.

●Lung transplant: Replaces a sick lung with a healthy lung from a person who has just died.

●Bullectomy: Removes the part of the lung that has been damaged by the formation of large, air-filled sacs called bullae. This surgery is rarely done.

alveoli [æl'viəlai] n.肺泡

antitrypsin ['ænti'tripsin] n.抗胰蛋白酶

bronchiectasis [,brɒŋki'ektəsis] n.支气管扩张

bronchiole ['brɒŋkiəʊl] n.细支气管

emphysema [,emf'siːmə] n.气肿；肺气肿

exacerbation [ek,sæsə'beiʃən] n.恶化；激怒；

irritant ['irit(ə)nt] n. 刺激物，刺激剂

marijuana [,mæri'hwɑːnə] n.大麻；大麻毒品

mucus ['mjuːkəs] n.黏液

neonatal [,niːə(ʊ)'neit(ə)l] adj.新生的；初生的

preterm [priː'tɜːm] n.早产，早产婴儿

spirometer [spai'rɒmitə] n.呼吸量计；肺活量计

bronchial tube 支气管

chronic bronchitis 慢性支气管炎

chronic obstructive pulmonary disease (COPD) 慢性阻塞性肺病

cystic fibrosis 囊胞性纤维症

elastic fibers 弹性纤维

forced expiratory volume 用力呼气量；强力呼气容积

oxygen saturation 氧饱和；氧饱和度

pulmonary fibrosis 肺纤维化