Chronic obstructive pulmonary disease (COPD) refers to chronic bronchitis and emphysema, a pair of two commonly co-existing diseases of the lungs in which the airways become narrowed. This leads to a limitation of the flow of air to and from the lungs causing shortness of breath. In contrast to asthma, the limitation of airflow is poorly reversible and usually gets progressively worse over time.

COPD is a classification of numerous bronchial conditions pooled together by pharmaceutical companies in order to broadly market their drugs. COPD is caused by noxious particles or gas, most commonly from tobacco smoking, which triggers an abnormal inflammatory response in the lung. The inflammatory response in the larger airways is known as chronic bronchitis, which is diagnosed clinically when people regularly cough up sputum. In the alveoli, the inflammatory response causes destruction of the tissues of the lung, a process known as emphysema. The natural course of COPD is characterized by occasional sudden worsening of symptoms called acute exacerbations, most of which are caused by infections or air pollution.

The diagnosis of COPD requires lung function tests. Important management strategies are smoking cessation, vaccinations, rehabilitation, and drug therapy (often using inhalers). Some patients go on to requiring long-term oxygen therapy or lung transplantation.

COPD is also known as chronic obstructive lung disease (COLD), chronic obstructive airway disease (COAD), chronic airflow limitation (CAL) and chronic obstructive respiratory disease (CORD).

Most cases of COPD develop after long-term exposure to lung irritants that damage the lungs and the airways.

In the United States, the most common irritant that causes COPD is cigarette smoke. Pipe, cigar, and other types of tobacco smoke also can cause COPD, especially if the smoke is inhaled. Secondhand smoke—that is, smoke in the air from other people smoking—also can irritate the lungs and contribute to COPD.

Breathing in air pollution and chemical fumes or dust from the environment or workplace also can contribute to COPD.

In rare cases, a genetic condition called alpha-1 antitrypsin deficiency may play a role in causing COPD. People who have this condition have low levels of alpha-1 antitrypsin (AAT)—a protein made in the liver.

Having a low level of the AAT protein can lead to lung damage and COPD if you're exposed to smoke or other lung irritants. If you have this condition and smoke, COPD can worsen very quickly.

The signs and symptoms of COPD include:

• An ongoing cough or a cough that produces large amounts of mucus (often called "smoker's cough")
• Shortness of breath, especially with physical activity
• Wheezing (a whistling or squeaky sound when you breathe)
• Chest tightness

These symptoms often occur years before the flow of air into and out of the lungs declines. However, not everyone who has these symptoms has COPD. Likewise, not everyone who has COPD has these symptoms.

Some of the symptoms of COPD are similar to the symptoms of other diseases and conditions. Your doctor can determine if you have COPD.

If you have COPD, you may have frequent colds or flu. If your COPD is severe, you may have swelling in your ankles, feet, or legs; a bluish color on your lips due to low levels of oxygen in your blood; and shortness of breath.

COPD symptoms usually slowly worsen over time. At first, if symptoms are mild, you may not notice them, or you may adjust your lifestyle to make breathing easier. For example, you may take the elevator instead of the stairs.

Over time, symptoms may become bad enough to see a doctor. For example, you may get short of breath during physical exertion.

How severe your symptoms are depends on how much lung damage you have. If you keep smoking, the damage will occur faster than if you stop smoking. In severe COPD, you may have other symptoms, such as weight loss and lower muscle endurance.

Some severe symptoms may require treatment in a hospital. You—with the help of family members or friends, if you're unable—should seek emergency care if:

• You're having a hard time catching your breath or talking.
• Your lips or fingernails turn blue or gray. (This is a sign of a low oxygen level in your blood.)
• You're not mentally alert.
• Your heartbeat is very fast.
• The recommended treatment for symptoms that are getting worse isn't working.

Your doctor will diagnose COPD based on your signs and symptoms, your medical and family histories, and test results.

He or she may ask whether you smoke or have had contact with lung irritants, such as air pollution, chemical fumes, or dust. If you have an ongoing cough, your doctor may ask how long you've had it, how much you cough, and how much mucus comes up when you cough. He or she also may ask whether you have a family history of COPD.

Your doctor will examine you and use a stethoscope to listen for wheezing or other abnormal chest sounds.

You also may need one or more tests to diagnose COPD.

Lung Function Tests

Lung function tests measure how much air you can breathe in and out, how fast you can breathe air out, and how well your lungs can deliver oxygen to your blood.

The main test for COPD is spirometry. Other lung function tests, such as a lung diffusing capacity test, also may be used. (For more information, see "Types of Lung Function Tests.")

Spirometry

During this painless test, a technician will ask you to take a deep breath in and then blow as hard as you can into a tube connected to a small machine. The machine is called a spirometer.

The machine measures how much air you breathe out. It also measures how fast you can blow air out.

Your doctor may have you inhale medicine that helps open your airways and then blow into the tube again. He or she can then compare your test results before and after taking the medicine.
Spirometry can detect COPD long before its symptoms appear. Doctors also may use the results from this test to find out how severe your COPD is and to help set your treatment goals.
The test results also may help find out whether another condition, such as asthma or heart failure, is causing your symptoms.
Other Tests
Your doctor may recommend other tests. These tests include:

• A chest x ray or chest computed tomography (CT) scan. These tests create pictures of the structures inside your chest, such as your heart and lungs. The pictures can show signs of COPD. They also may show whether another condition, such as heart failure, is causing your symptoms.
• An arterial blood gas test. This blood test measures the oxygen level in your blood using a sample of blood taken from an artery. The test can help find out how severe your COPD is and whether you may need supplemental oxygen therapy.

COPD has no cure yet. However, treatments and lifestyle changes can help you feel better, stay more active, and slow the progress of the disease.
Quitting smoking is the most important step you can take to treat COPD. Talk to your doctor about programs and products that can help you quit. Many hospitals have programs that help people quit smoking, or hospital staff can refer you to a program. Ask your family members and friends to support you in your efforts to quit. Also, try to avoid secondhand smoke.
Other treatments for COPD may include medicines, vaccines, pulmonary rehabilitation (rehab), oxygen therapy, surgery, and managing complications.
The goals of COPD treatment are to:
•    Relieve your symptoms
•    Slow the progress of the disease
•    Improve your exercise tolerance (your ability to stay active)
•    Prevent and treat complications
•    Improve your overall health

Specialists Involved
To assist with your treatment, your family doctor may advise you to see a pulmonologist. This is a doctor who specializes in treating people who have lung problems.

Medicines
Bronchodilators
Bronchodilators relax the muscles around your airways. This helps open your airways and makes breathing easier.
Depending on how severe your disease is, your doctor may prescribe short-acting or long-acting bronchodilators. Short-acting bronchodilators last about 4 to 6 hours and should be used only when needed. Long-acting bronchodilators last about 12 hours or more and are used every day.
Most bronchodilators are taken using a device called an inhaler. This device allows the medicine to go right to your lungs. Not all inhalers are used the same way. Ask your health care team to show you the right way to use your inhaler.
If your COPD is mild, your doctor may only prescribe a short-acting inhaled bronchodilator. In this case, you may only use the medicine when symptoms occur.
If your COPD is moderate or severe, your doctor may prescribe regular treatment with short- and long-acting bronchodilators.

Inhaled Glucocorticosteroids (Steroids)
Inhaled steroids are used for some people who have moderate or severe COPD. These medicines may reduce airway inflammation (swelling).
Your doctor may ask you to try inhaled steroids for a trial period of 6 weeks to 3 months to see whether the medicine is helping with your breathing problems.

Vaccines
Flu Shots
The flu (influenza) can cause serious problems for people who have COPD. Flu shots can reduce your risk for the flu. Talk with your doctor about getting a yearly flu shot.

Pneumococcal Vaccine
This vaccine lowers your risk for pneumococcal pneumonia and its complications. People who have COPD are at higher risk for pneumonia than people who don't have COPD. Talk with your doctor about whether you should get this vaccine.

Pulmonary Rehabilitation
Pulmonary rehab is a medically supervised program that helps improve the health and well-being of people who have lung problems. Rehab may include an exercise program, disease management training, and nutritional and psychological counseling. The program aims to help you stay more active and carry out your day-to-day activities.
Your rehab team may include doctors, nurses, physical therapists, respiratory therapists, exercise specialists, and dietitians. These health professionals work together and with you to create a program that meets your needs.

Oxygen Therapy
If you have severe COPD and low levels of oxygen in your blood, oxygen therapy can help you breathe better. For this treatment, you're given oxygen through nasal prongs or a mask.
You may need extra oxygen all the time or just sometimes. For some people who have severe COPD, using extra oxygen for most of the day can help them:
•    Do tasks or activities, while having fewer symptoms
•    Protect their hearts and other organs from damage
•    Sleep more during the night and improve alertness during the day
•    Live longer

Surgery
In rare cases, surgery may benefit some people who have COPD. Surgery usually is a last resort for people who have severe symptoms that have not improved from taking medicines.
Surgeries for people who have COPD that's mainly related to emphysema include bullectomy (bul-EK-to-me) and lung volume reduction surgery (LVRS). A lung transplant may be done for people who have very severe COPD.

Bullectomy
When the walls of the air sacs are destroyed, larger air spaces called bullae form. These air spaces can become so large that they interfere with breathing. In a bullectomy, doctors remove one or more very large bullae from the lungs.

Lung Volume Reduction Surgery
In LVRS, surgeons remove damaged tissues from the lungs. This helps the lungs work better. In carefully selected patients, LVRS can improve breathing and quality of life.

Lung Transplant
A lung transplant may benefit some people who have very severe COPD. During a lung transplant, your damaged lung is removed and replaced with a healthy lung from a deceased donor.
A lung transplant can improve your lung function and quality of life. However, lung transplants have a high risk of complications. These include infections and death due to the body rejecting the transplanted lung.
If you have very severe COPD, talk to your doctor about whether a lung transplant is an option. Discuss with your doctor the benefits and risks of this type of surgery.

Managing Complications
COPD symptoms usually slowly worsen over time. However, they can become more severe suddenly. For instance, a cold, the flu, or a lung infection may cause your symptoms to quickly worsen. You may have a much harder time catching your breath. You also may have chest tightness, more coughing, changes in the color or amount of your sputum (spit), and a fever.
Call your doctor right away if this happens. He or she may prescribe antibiotics to treat the infection and other medicines, such as bronchodilators and glucocorticosteroids, to help with your breathing.

You can take steps to prevent COPD before it starts. If you already have COPD, you can take steps to prevent complications and slow the progress of the disease.

Prevent COPD Before It Starts
The best way to prevent COPD is to not start smoking or to quit smoking before you develop the disease. Smoking is the leading cause of COPD.
If you smoke, talk to your doctor about programs and products that can help you quit. Many hospitals have programs that help people quit smoking, or hospital staff can refer you to a program. Also, try to avoid secondhand smoke and other lung irritants that can contribute to COPD, such as air pollution, chemical fumes, and dust.

Prevent Complications and Slow the Progress of COPD
If you have COPD, the most important step you can take is to quit smoking. This can help prevent complications and slow the progress of the disease. You also should avoid exposure to the lung irritants mentioned above.
Follow your treatments for COPD exactly as your doctor prescribes. They can help you breathe easier, stay more active, and avoid or manage severe symptoms.
Talk with your doctor about whether and when you should get flu and pneumonia vaccines. These vaccines can lower your chances of getting these illnesses, which are major health risks for people who have COPD.

The main risk factor for COPD is smoking. Most people who have COPD smoke or used to smoke. People who have a family history of COPD are more likely to get the disease if they smoke.
Long-term exposure to other lung irritants also is a risk factor for COPD. Examples of other lung irritants include air pollution and chemical fumes and dust from the environment or workplace.
Most people who have COPD are at least 40 years old when symptoms begin. Although it isn't common, people younger than 40 can have COPD. For example, this may happen if a person has alpha-1 antitrypsin deficiency, a genetic condition.