Chronic Obstructive Pulmonary Disease (COPD): Takes Your Breath Away

Harvard Health

Smoking is responsible for about 85 percent of COPD cases; heavy smokers are at highest risk

Smoking is responsible for about 85 percent of COPD cases; heavy smokers are at highest risk.

Harvard Health Letters

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. It's expected to take about 126,000 lives this year, making it the only one of the 10 leading killers that's increasing each year. And COPD is also a major cause of disability since some 24 million Americans suffer from the condition; although it has traditionally been a predominantly male disease, COPD is on the rise in American women.

COPD is not curable but it is treatable. Lifestyle changes and medication can help patients cope with chronic lung disease and live longer, fuller lives. And if you understand COPD, you'll know that most cases can be prevented.

NORMAL LUNGS

The average person takes more than 20,000 breaths a day. With each, air travels down the windpipe, or trachea, then through smaller tubes called bronchi. The linings of the bronchi are studded with mucous glands that add moisture to the incoming air, and their walls contain muscles that can make the tubes wider or narrower. After passing through the bronchi, the air arrives at its final destination, the lung's 300 million tiny air sacs, or alveoli. Here, oxygen enters the blood to nourish the body's tissues, and carbon dioxide makes its way out of the bloodstream.

The work of breathing is powered by the muscles of the chest wall and the diaphragm, the strong muscle that separates the chest from the abdomen. As you inhale, your chest expands and your bronchi widen; when you exhale, the reverse occurs. Because the bronchi are narrowed, it normally takes longer to exhale than to inhale; the narrower your bronchi, the longer it takes to expel air from your lungs.

In COPD, the bronchi are abnormally narrow, so the flow of air is obstructed, and breathing is hard.

In healthy lungs, millions of alveoli exchange oxygen for carbon dioxide. A fine web of blood vessels picks up oxygen to be used by tissues and organs throughout the body.

In patients with emphysema, air sacs are damaged and stale air is trapped. When chronic bronchitis is also present, the bronchioles are narrowed and clogged by mucus.

WHAT IS COPD?

COPD is a complex disorder. There are two major forms of the disease, chronic bronchitis and emphysema. In both, narrowed bronchi make it hard to exhale. Narrowed bronchi also cause asthma -- but in asthma, the narrowing is temporary and reversible, while in COPD, it's permanent.

In chronic bronchitis, an enlargement of the mucous glands and excessive mucus production cause the narrowing. In emphysema, the narrowing comes from damage to the bronchi themselves and is more severe. Most patients with COPD have a mixture of chronic bronchitis and emphysema.

Narrowed bronchial tubes are the hallmark of COPD, but the damage doesn't stop there. It takes more force to exhale through narrow airways, and, in emphysema, the air sacs become hyperinflated, filled with too much air. But pressure is not the main culprit in emphysema. Rather, it's inflammation triggered by inhaled irritants.

White blood cells respond to the irritation, but instead of controlling the problem, they release chemicals that damage and eventually destroy lung tissue. Patients with chronic bronchitis are spared the worst aspects of tissue destruction, but they can still suffer significant damage.

WHAT CAUSES COPD?

Smoking is responsible for about 85 percent of cases; heavy smokers are at highest risk. Airborne toxins account for COPD in many nonsmokers; secondhand smoke is another likely contributor. In others, an inherited deficiency of a protein (alpha-1 antitrypsin) that keeps the lungs healthy is to blame. But in some cases, no cause is apparent.

SYMPTOMS

COPD starts gradually and progresses slowly; that's why cases continue to increase years after many Americans quit smoking.

At first, there are no symptoms -- but little by little, problems appear, usually in middle age. A morning "smoker's cough" is often the first complaint. The cough gradually gets worse and occurs throughout the day. Next, shortness of breath develops. In the beginning, patients only notice shortness of breath during exercise, but as the disease progresses, breathing becomes a chore even at rest. Wheezing is another common symptom. Most patients also become tired and weak; morning headaches may be prominent.

Patients with chronic bronchitis have a recurrent cough that brings up large amounts of thick, discolored phlegm almost every day for three months or longer. Over time, the lung disease puts a strain on the heart, and patients develop a type of heart failure called cor pulmonale. As a result, they accumulate fluid (edema) and gain weight. Their lips and skin may eventually look bluish (cyanotic) due to low blood-oxygen levels. Doctors may use the slang term "blue bloaters" to describe the combination of cyanosis and edema.

Patients with emphysema look different. Their cough is scant and dry but their shortness of breath is more severe, and they breathe faster than normal. They stay pink and don't accumulate fluid, but they lose weight, their muscles tend to waste away, and they develop large, barrel-shaped chests. Because of their rapid breathing and pink skin, doctors may call these patients "pink puffers."

Most patients with COPD have mixed features of chronic bronchitis and emphysema. And in addition to daily symptoms, most have two to three exacerbations each year. These are abrupt flares that are often triggered by lung infections. Up to 25 percent of patients hospitalized for severe exacerbations also have blood clots in their lungs (pulmonary emboli). Symptoms get much worse and aggressive treatment is needed.

DIAGNOSIS

Your doctor will ask about your smoking history and about possible exposure to secondhand smoke, fumes, and dust particles. You should also report any family history of COPD and symptoms such as coughing, phlegm, shortness of breath, wheezing, fatigue, and changes in your weight.

A physical examination can suggest the diagnosis of COPD. Your doctor will check your lips, skin, and nails for bluish discoloration that suggests low oxygen levels. Your nails may be abnormally rounded (clubbed), and you may have edema fluid in your legs and feet.

Your chest exam is most important. If your problem is chronic bronchitis, your doctor may hear wheezing and abnormal gurgling sounds (rales) through a stethoscope. If emphysema is the main problem, your chest may be enlarged and sound hollow when your doctor taps on it. Even through a stethoscope, your breath sounds will be soft and distant.

If you have emphysema, your chest X-ray will show enlarged lungs filled with an excessive amount of air. Scarring and large air-filled cavities (blebs and bullae) may also be evident. The x-ray abnormalities of chronic bronchitis are less specific. CT scans can show damage at an earlier stage, but no imaging test can accurately gauge the severity of COPD or predict its outcome.

In many cases, your doctor will order additional tests such as complete blood counts, an ECG (electrocardiogram) to look for heart strain, an analysis of your sputum, and a test to measure the oxygen in your blood. But the most important test of all is a lung function test called forced expiratory volume in one second (FEV1). It measures the amount of air you can breathe out with a maximal effort in one second.

The test is simple and safe. You take a deep breath in, then blow out as fast and hard as you can into a spirometer, which collects the air and measures the amount you've exhaled in the first second.

Normal values for the FEV1 depend on a person's age, sex, and height. Doctors can diagnose COPD and estimate its severity based on how a patient's FEV1 compares to his predicted normal values. By repeating lung function tests, doctors can tell if COPD is getting worse. And they can also tailor therapy to the stage of the disease.

Estimating the severity of COPD

Stage 1: Mild COPD. FEV1 at least 80 percent of predicted

Stage 2: Moderate COPD. FEV1 between 50 percent and 80 percent of predicted

Stage 3: Severe COPD. FEV1 between 30 percent and 50 percent of predicted

Stage 4: Very severe COPD. FEV1 below 30 percent of predicted

(FEV1: Forced expiratory volume in one second)

TREATMENT: LIFESTYLE

-- Avoid tobacco -- it's the first rule in prevention, and the most important. And it applies to second-hand smoke, too. No exceptions.

-- Good nutrition is also important. A Harvard study of 42,917 men found that a high intake of fruits, vegetables, whole grains, and fish appears to protect the lungs and reduce the risk of COPD, while refined grains, red meat, and cured meats all increase risk. There is no evidence that vitamin supplements help, and one, beta carotene, increases a smoker's risk of lung cancer. Patients with chronic bronchitis and heart strain must avoid sodium (salt). Patients with severe emphysema are often emaciated and may benefit from high-calorie nutritional supplements. Good hydration is important to keep phlegm loose and easy to cough out.

-- Exercise makes patients huff and puff, but a gradual program of low-to-moderate-intensity exercise helps muscles get the most bang out of the oxygen that damaged lungs can deliver. Walking is best, starting with five minutes three to four times a day, then building up to as much as 45 minutes a day. Patients with severe COPD or heart disease may need supervision. Structured pulmonary rehabilitation programs also offer breathing exercises designed to strengthen chest muscles.

-- Preventing infection is essential. Be sure your flu and pneumococcal pneumonia immunizations are up to date. Keep your distance from folks with respiratory infections, particularly the flu. Wash your hands carefully, using an alcohol-based hand rub.

TREATMENT: MEDICATIONS

Prescription medications can do a lot for patients with COPD. Your doctor will decide what's best for you and will explain the likely benefits and possible side effects. Here's a summary of the major groups of medications:

-- Bronchodilators relax the muscles in the walls of the bronchi, widening the tubes and easing the passage of air. The most popular short-acting bronchodilator is albuterol, which is inhaled through a metered-dose inhaler (MDI) up to four times a day for quick relief of wheezing, coughing, or shortness of breath.

Patients with mild COPD may need only a short-acting bronchodilator, but patients with more advanced disease also benefit from a long-acting bronchodilator. Although these medications have been controversial in asthma, they appear safe and effective in COPD when used carefully and properly. Salmeterol, formoterol, and arformoterol can be inhaled twice a day from an MDI, from a dry powder inhaler (DPI), or from a nebulizer. Long-acting bronchodilators are used to prevent symptoms, not provide rapid relief; patients taking these medications should continue using their short-acting bronchodilators for rapid relief.

-- Corticosteroids ("steroids") reduce inflammation in the bronchial tubes. Inhaled steroids can help many, but not all, patients with moderate to severe COPD. They are most effective for patients who are also taking long-acting bronchodilators.

Steroids are also available in oral and injectable forms. These preparations have powerful anti-inflammatory effects but can also produce serious side effects. Whereas inhaled steroids are desirable for long-term maintenance of patients with COPD, steroid tablets and injections are used only for short-term treatment of severe flares or exacerbations.

-- Anticholinergics are drugs that widen the bronchial tubes and also reduce the volume of secretions without making sputum thick and hard to raise. They are inhaled for long-term control; the newer drug tiotropium can be used just once a day, while ipratropium must be administered twice a day. Tiotropium has been widely used for COPD with good results and may even slow the progression of early COPD. Because the anticholinergics and bronchodilators work in different ways, patients can benefit from using both types of drugs.

-- Antibiotics are not helpful for maintenance therapy but can be critically important for exacerbations or flares. Notify your doctor promptly if your breathing becomes worse, if you develop a fever, or if your phlegm becomes thicker, discolored, or more abundant.

TREATMENT: OXYGEN

COPD patients who have low blood-oxygen levels can benefit greatly from long-term, round-the-clock oxygen therapy. For home use, oxygen can be stored in cylinders or generated by machines called oxygen concentrators. Portable tanks can provide several hours of oxygen away from home. Safe oxygen therapy requires responsible cooperation by patients and household members.

TREATMENT: SURGERY

Select patients with severe emphysema may benefit from special types of lung operations. Expert evaluation by experienced physicians is mandatory. A few COPD patients may be eligible for lung transplantation.

LIVING WITH COPD

During the course of a lifetime, the average person will take some 600 million breaths. Most people can keep their lungs healthy simply by avoiding tobacco smoke and other noxious fumes; a good diet should also help. And even when COPD causes damage, early diagnosis and treatment can slow the process, ward off complications, and improve quality of life. New therapies are on the way, but simple prevention is the best treatment of all. And, after all, what's more important than preserving the breath of life? - Harvard Men's Health Watch

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