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When Asthma and COPD Coexist
By Brian A. Smart, MD

Asthma and COPD (Chronic Obstructive Pulmonary Disease), which includes emphysema and chronic bronchitis, are common respiratory ailments that can affect people for many years. Asthma can affect people at any point in their lives, whereas COPD more often impacts seniors. Asthma and COPD also can coexist in the same individual. It is important to understand the similarities and differences between the diagnosis, treatment and long-term outcome of asthma and COPD.

Asthma and COPD have very different definitions. Asthma is now believed to be a disease of long-term inflammation, sort of like a rash in your lungs. Like a rash, the lung inflammation in asthma can be triggered by contact with substances that trigger allergies. Common allergic triggers in asthma include house dust mites, cockroaches, molds, pet danders and pollens. The lung inflammation in asthma is best treated with anti-inflammatory medications, such as inhaled corticosteroids. Finally, asthma is similar to a rash in that, when treated properly, the inflammation may improve. Similar to asthma, patients with COPD have some long-term inflammation. However, in contrast to asthma, the inflammation is not triggered by allergies and does not respond well to anti-inflammatory medication. In fact, the lungs of patients with COPD have evidence of permanent damage with destruction and plugging of the airways.

Asthma and COPD can both cause chest symptoms such as shortness of breath, coughing and wheezing. Patients with asthma are more likely, however, to have episodic chest symptoms, nighttime chest symptoms and chest symptoms after exposure to allergic triggers than patients with COPD. In contrast, patients with COPD are more likely to have a daily morning cough that produces mucus and persistent chest symptoms throughout the day.

Smoking causes damage under any circumstances. A long-term history of smoking is very common in patients with COPD, and continued smoking worsens the permanent lung damage in these patients. Patients with asthma also worsen with smoking. Many patients with co-existent asthma and COPD have had asthma for many years and cause the additional permanent lung damage of COPD by smoking.

Medical exam
Your doctor is more likely, while listening to your chest, to hear wheezing with asthma and is more likely to hear "distant" or reduced breath sounds with COPD. Also, a "barrel chest," or barrel-shaped chest due to the trapping of air, is more characteristic of COPD than asthma.

Medical tests
Chest X-rays may be normal in both asthma and COPD. When abnormal findings are identified, these findings may include evidence for too much air in the lungs (air trapping), which is usually more pronounced in COPD than asthma. COPD patients may also show "increased lung markings." Allergies are common in patients with asthma and may be confirmed through allergy testing. In contrast, allergies appear to have nothing to do with COPD.

One of the most important tools your doctor may use to differentiate between asthma and COPD is the pulmonary function test (PFT). In both asthma and COPD, the PFT may show evidence for airway obstruction. However, in asthma, but not in COPD, the PFT may show improvement in obstruction after treatment with a bronchodilator, such as albuterol. In patients with both asthma and COPD, obstruction improves with a bronchodilator, but not to the same degree as with asthma alone.

Since asthma is often triggered by allergies and COPD is closely associated with smoking, controlling for allergies and quitting smoking can be very helpful in managing these diseases. Asthma is more of a lung-inflammation illness, while COPD is more of a lung-destruction illness. Therefore, anti-inflammatory medications, such as inhaled corticosteroids are the best long-term treatment for asthma but are not very beneficial for COPD. Both asthma and COPD can be treated with bronchodilators that help the airways to relax and "open up." Your physician is the most qualified individual to help you decide upon proper treatment. Please see your physician regularly to help you with your asthma and/or COPD.

The expected treatment goals of asthma and COPD may be very different. Many patients with asthma, once the lung inflammation is treated, can be virtually symptom-free. In contrast, most COPD patients have permanent lung damage. Many with COPD can experience some improvement in symptoms with treatment but the primary treatment goal is usually to slow the further loss of lung function. For individuals with both asthma and COPD, the expected outcome is an improvement in lung function but not to the degree as with asthma alone.

Brian A. Smart, MD, is a member of the American Academy of Allergy, Asthma and Immunology (AAAAI) and practices in a group allergy and asthma practice in Buffalo Grove, IL.

Source: Copyright 2001, Asthma Magazine Reprinted by permission.

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