For people with chronic respiratory conditions, getting an accurate diagnosis is the first step to getting appropriate treatment. Two common diseases that cause breathing difficulties are asthma and chronic obstructive pulmonary disease (COPD). Researchers in Australia recently announced that they have found a way to help doctors accurately diagnose whether a patient has COPD or asthma.
Defining Asthma
Asthma is a disease that can affect people of any age but usually starts in childhood. People with asthma may have relatively little difficulty breathing until something triggers an attack. During an asthma attack, tissue in the airways swells and secretes excess mucus. At the same time, the muscles around the airways tighten, which squeezes the airways. All of these things make it harder for air to pass in and out of the lungs, which can cause coughing and wheezing.
Defining Chronic Obstructive Pulmonary Disease
COPD is a progressive condition of the lungs that gets worse over time. Inside the lungs there are tiny air sacs formed by walls of a very thin membrane. When we breathe in, the sacs expand and fill with air. Blood vessels pick up oxygen from these sacs and carry it out to the body. When we breathe out, the sacs shrink down to help push the air out, along with carbon dioxide that was carried to the lungs by the blood. For people with COPD, the lungs are not able to function normally and less air moves in and out when they breathe. This can be caused by damage to the air sacs in the lungs, because the walls of the airways are inflamed and thicker than normal, or because the airways are producing too much mucus which blocks air flow.
COPD vs. Asthma
At first glance, it would seem that doctors should easily be able to tell the difference between asthma and COPD. Asthma usually starts in childhood while COPD often starts in adults who are smokers. Asthma is often triggered by recognizable events such as allergens, cold air, or exercise. COPD often becomes worse as a result of a respiratory tract infection. And asthma patients who are treating their condition can have almost normal lung function between asthma attacks while COPD patients have symptoms and some degree of breathing difficulty every day.
But the truth is that many patients who have COPD have been misdiagnosed and may receive treatment for asthma instead of COPD. This is significant because the two conditions have nearly opposite treatments.
• Asthma – Controlled by inhaled corticosteroids. Rescue treatment includes bronchodilators.
• COPD – Maintained by bronchodilators with corticosteroids used only for patients who need additional medication.
The research team in Australia believes they have found a way to use blood samples to determine whether a patient has COPD or asthma using an emerging branch of science known as proteomics. Proteomics focuses on studying the structure and functions of the proteins that are found in various organisms. Using these techniques, researchers identified four biomarkers in the blood that can be used in combination to distinguish between asthma and COPD in patients. COPD often causes disability and is the fourth leading cause of death in the United States. Because there is no cure for COPD, it is critical for doctors to correctly diagnose the condition and begin treatment as early as possible to slow the progression of the disease.
Sources:
American Association for Respiratory Care
Science Daily
National Heart Lung and Blood Institute: Asthma
National Heart Lung and Blood Institute: COPD