Chronic Obstructive Pulmonary Disease
The Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines COPD as a common, preventable, and treatable disease state characterized by persistent respiratory symptoms and airflow limitation due to airway and alveolar abnormalities usually caused by significant exposure to noxious particles or gases. Symptoms include cough, dyspnea, and sputum production. COPD is a major cause of chronic morbidity and mortality worldwide
Most patients with COPD have features of both emphysema and chronic bronchitis. Chronic bronchitis is a clinical diagnosis defined by excessive secretion of bronchial mucus and is manifested by daily productive cough for 3 months or more in at least 2 consecutive years.
Emphysema is a pathologic diagnosis that denotes abnormal permanent enlargement of air spaces distal to the terminal bronchiole, with destruction of alveolar walls and without obvious fibrosis.
Both of these definitions are no longer included in GOLD because they comprise a minority of patients. Chronic respiratory symptoms also exist in people with normal spirometry, and a number of smokers without airflow limitation will have varying degrees of emphysema.
What Causes COPD?
Most cases of COPD occur as a result of 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.
Breathing in secondhand smoke, air pollution, and chemical fumes or dust from the environment or workplace also can contribute to COPD. (Secondhand smoke is smoke in the air from other people smoking.)
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.
What are the Signs and Symptoms of COPD?
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 find out whether you have COPD.
If you have COPD, you may have colds or the flu (influenza) frequently. If your COPD is severe, you may have swelling in your ankles, feet, or legs; a bluish color on your lips due to a low blood oxygen level; 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 severe 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.
Radiographs of patients with chronic bronchitis typically show only nonspecific peribronchial and perivascular markings. Plain radiographs are insensitive for the diagnosis of emphysema; they show hyperinflation with flattening of the diaphragm or peripheral arterial deficiency in about half of cases.
CT of the chest, particularly using high-resolution CT, is more sensitive and specific than plain radiographs for its diagnosis. In advanced disease, pulmonary hypertension may be suggested by enlargement of central pulmonary arteries on radiographs, and Doppler echocardiography provides an estimate of pulmonary artery pressure.
Clinical, imaging, and laboratory findings should enable the clinician to distinguish COPD from other obstructive pulmonary disorders, such as asthma, bronchiectasis, cystic fibrosis, bronchopulmonary mycosis, and central airflow obstruction. Asthma is characterized by complete or nearcomplete reversibility of airflow obstruction.
Bronchiectasis is distinguished from COPD by recurrent pneumonia and hemoptysis, digital clubbing, and characteristic imaging abnormalities. Patients with severe alpha-1-antitrypsin deficiency have a family history of the disorder and the finding of panacinar bibasilar emphysema early in life, usually in the third or fourth decade; hepatic cirrhosis and hepatocellular carcinoma may develop.
Cystic fibrosis occurs in children, adolescents, and young adults. Mechanical obstruction of the central airways can be distinguished from COPD by flow-volume loops.
How is COPD Treated?
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 with your doctor about programs and products that can help you quit.
Also, try to avoid secondhand smoke. (Secondhand smoke is smoke in the air from other people smoking.) Other treatments for COPD may include medicines, vaccines, pulmonary rehabilitation (rehab), oxygen therapy, and surgery. Your doctor also may recommend tips for managing COPD complications.
Bronchodilators relax the muscles around your airways. This helps open your airways and makes breathing easier.
Inhaled steroids are used to treat people whose COPD symptoms flare up or worsen. These medicines may reduce airway inflammation.
The flu (influenza) can cause serious problems for people who have COPD. Flu shots can reduce your risk of the flu.
Pneumococcal Vaccine. This vaccine lowers your risk of pneumococcal pneumonia (nu-MO-ne-ah) and its complications. People who have COPD are at higher risk of pneumonia than people who don’t have COPD.
Pulmonary rehabilitation, or rehab, is a medically supervised program that helps improve the health and well-being of people who have lung problems.
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.
Acute bronchitis, pneumonia, pulmonary thromboembolism, atrial dysrhythmias (such as atrial fibrillation, atrial flutter, and multifocal atrial tachycardia), and concomitant left ventricular failure may worsen otherwise stable COPD. Pulmonary hypertension, cor pulmonale, and chronic respiratory failure are common in advanced COPD. Spontaneous pneumothorax occurs in a small fraction of patients with emphysema. Hemoptysis may result from chronic bronchitis or may signal bronchogenic carcinoma.
COPD is largely preventable through elimination of longterm exposure to tobacco smoke, combustion of biomass fuels, and other inhaled toxins. Smokers with early evidence of airflow limitation can significantly alter their disease by smoking cessation. Smoking cessation slows the decline in FEV1 in middle-aged smokers with mild airways obstruction. Influenza vaccination reduces the frequency and severity of influenza-like illness as well as the number of COPD exacerbations. Pneumococcal vaccination appears to reduce both the frequency of community-acquired pneumonia and the number of COPD exacerbations.