Obstructive lung diseases, according to their classification by the National Library of Medicine (NLM), include "any disorder marked by obstruction of conducting airways of the lung." These disorders "may be acute chronic, intermittent, or persistent." The NLM lists three main categories of obstructive lung diseases: asthma, bronchitis and chronic obstructive pulmonary disease.
Asthma
Asthma is characterized by recurring bouts of coughing, wheezing, breathlessness and chest tightness, which are triggered by environmental factors, such as tobacco smoke, according to the Centers for Disease Control and Prevention. When people with asthma encounter one of these environmental triggers, the airways in their lungs become swollen and filled with mucus, thus narrowing the space available for air to flow through. While asthma is treatable, researchers haven't determined the underlying cause of the condition, and no cure has been found.
Bronchitis
Bronchitis, which can be acute or chronic, refers to inflammation of the air passages, called bronchial tubes, in the lungs. The acute form of bronchitis is usually caused by a cold or other respiratory infection, according to the Mayo Clinic website. Acute bronchitis is usually short lived, with negligible consequences. Chronic bronchitis, on the other hand, is more serious and is one of the basic components of chronic obstructive pulmonary disease (COPD). A common cause of chronic bronchitis is smoking.
Chronic Obstructive Pulmonary Disease
COPD is one of the leading causes of death in the United States, according to the Centers for Disease Control. The American Thoracic Society characterizes the disease as causing progressively limited airflow that is not fully reversible. COPD is caused by abnormal inflammation in the lungs, which results from chronic bronchitis, emphysema or a combination of those two conditions.
Other Obstructive Lung Diseases
Some clinicians, including those at the American Thoracic Society, note that other lung diseases may also have a poor airflow component. Among these are bronchiectasis, cystic fibrosis and fibrosis caused by tuberculosis. Bronchiectasis, which the National Library of Medicine defines as an injury to the air passages leading to "recurrent inflammation or infection of the airways." It can be congenital or acquired, with cystic fibrosis as the precipitating factor in about 50 percent of acquired cases. Fibrosis is the build up of thick, fibrous tissues in the lungs or airways, making them stiff and inflexible, leading to poor airflow.
The NLM classification system does not include emphysema among obstructive lung diseases, as emphysema results from the destruction of the small air sacs in the lungs, rather than from obstruction to the airways. However, the result is similar--poor oxygen exchange and the inability to catch your breath--which is why this disease is a major component in COPD and is often grouped with other obstructive lung diseases.
