Chronic Obstructive Pulmonary Disease; What is it?

 Chronic obstructive pulmonary disease (COPD) refers to a group of lung diseases that block airflow and make breathing difficult.

Emphysema and chronic bronchitis are the two most common conditions that make up COPD. Chronic bronchitis is an inflammation of the lining of your bronchial tubes, which carry air to and from your lungs. Emphysema occurs when the air sacs (alveoli) at the end of the smallest air passages (bronchioles) in the lungs are gradually destroyed.

Damage to your lungs from COPD can't be reversed, but treatment can help control symptoms and minimize further damage.

SYMPTOMS

Symptoms of COPD often don't appear until significant lung damage has occurred, and they usually worsen over time. For chronic bronchitis, the main symptom is a cough that you have at least three months a year for two consecutive years. Other signs and symptoms of COPD include:

• Shortness of breath, especially during physical activities
• Wheezing
• Chest tightness
• Having to clear your throat first thing in the morning, due to excess mucus in your lungs
• A chronic cough that produces sputum that may be clear, white, yellow or greenish
• Blueness of the lips or fingernail beds (cyanosis)
• Frequent respiratory infections
• Lack of energy
• Unintended weight loss (in later stages)

People with COPD are also likely to experience episodes called exacerbations, during which their symptoms become worse and persist for days or longer.

CAUSES

The main cause of COPD is tobacco smoking. However, in the developing world, COPD often occurs in women exposed to fumes from burning fuel for cooking and heating in poorly ventilated homes. Only about 20 percent of chronic smokers develop COPD. Some smokers develop less common lung conditions. They may be misdiagnosed as having COPD until a more thorough evaluation is performed.

How your lungs are affected

Air travels down your windpipe (trachea) and into your lungs through two large tubes (bronchi). Inside your lungs, these tubes divide many times — like the branches of a tree — into many smaller tubes (bronchioles) that end in clusters of tiny air sacs (alveoli). The air sacs have very thin walls full of tiny blood vessels (capillaries). The oxygen in the air you inhale passes into these blood vessels and enters your bloodstream. At the same time, carbon dioxide — a gas that is a waste product of metabolism — is exhaled.

Your lungs rely on the natural elasticity of the bronchial tubes and air sacs to force air out of your body. COPD causes them to lose their elasticity and partially collapse, which leaves some air trapped in your lungs when you exhale.

Causes of airway obstruction

• Emphysema. This lung disease causes destruction of the fragile walls and elastic fibers of the alveoli. Small airways collapse when you exhale, impairing airflow out of your lungs.
• Chronic bronchitis. In this condition, your bronchial tubes become inflamed and narrowed and your lungs produce more mucus, which can further block the narrowed tubes. You develop a chronic cough trying to clear your airways.

Medications

Doctors use several kinds of medications to treat the symptoms and complications of COPD. You may take some medications on a regular basis and others as needed:

• Bronchodilators. These medications — which usually come in an inhaler — relax the muscles around your airways. This can help relieve coughing and shortness of breath and make breathing easier. Depending on the severity of your disease, you may need a short-acting bronchodilator before activities, a long-acting bronchodilator that you use every day, or both.

  Short-acting bronchodilators include albuterol (ProAir HFA, Ventolin HFA, others), levalbuterol (Xopenex), and ipratropium (Atrovent). The long-acting bronchodilators include tiotropium (Spiriva), salmeterol (Serevent), formoterol (Foradil, Perforomist), arformoterol (Brovana), indacaterol (Arcapta) and aclidinium (Tudorza).

• Inhaled steroids. Inhaled corticosteroid medications can reduce airway inflammation and help prevent exacerbations. Side effects may include bruising, oral infections and hoarseness. These medications are useful for people with frequent exacerbations of COPD. Fluticasone (Flovent) and budesonide (Pulmicort) are examples of inhaled steroids.
• Combination inhalers. Some medications combine bronchodilators and inhaled steroids. Salmeterol and fluticasone (Advair) and formoterol and budesonide (Symbicort) are examples of combination inhalers.
• Oral steroids. For people who have a moderate or severe acute exacerbation, oral steroids prevent further worsening of COPD. However, these medications can have serious side effects, such as weight gain, diabetes, osteoporosis, cataracts and an increased risk of infection.
• Phosphodiesterase-4 inhibitors. A new type of medication approved for people with severe COPD is roflumilast (Daliresp), a phosphodiesterase-4 inhibitor. This drug decreases airway inflammation and relaxes the airways. Common side effects include diarrhea and weight loss.
• Theophylline. This very inexpensive medication helps improve breathing and prevents exacerbations. Side effects may include nausea, fast heartbeat and tremor.
• Antibiotics. Respiratory infections, such as acute bronchitis, pneumonia and influenza, can aggravate COPD symptoms. Antibiotics help fight acute exacerbations. The antibiotic azithromycin prevents exacerbations, but it isn't clear whether this is due to its antibiotic effect or its anti-inflammatory properties.

Lung therapies

Doctors often use these additional therapies for people with moderate or severe COPD:

• Oxygen therapy. If there isn't enough oxygen in your blood, you may need supplemental oxygen. There are several devices to deliver oxygen to your lungs, including lightweight, portable units that you can take with you to run errands and get around town. Some people with COPD use oxygen only during activities or while sleeping. Others use oxygen all the time. Oxygen therapy can improve quality of life and is the only COPD therapy proven to extend life. Talk to your doctor about your needs and options.
• Pulmonary rehabilitation program. These programs typically combine education, exercise training, nutrition advice and counseling. You'll work with a variety of specialists, who can tailor your rehabilitation program to meet your needs. Pulmonary rehabilitation may shorten hospitalizations, increase your ability to participate in everyday activities and improve your quality of life. Talk to your doctor about referral to a program.