Chronic Obstructive Pulmonary Disease
Alternate Names : COPD, Chronic Obstructive Lung Disease (COLD)
Chronic obstructive pulmonary disease, also called COPD, is actually a group of lung diseases. People with COPD have limitations in the airflow through their airways. The limitation usually worsens over time. Lungs of people with COPD become easily inflamed from noxious particles or gases. The airways produce extra mucus, which is coughed up as sputum.
Chronic bronchitis and emphysema are two common types of COPD. Chronic bronchitis is
an ongoing inflammation of the large airways. Emphysema is a chronic disease in which the tissues of the lungs are gradually destroyed.
What is going on in the body?
Chronic obstructive pulmonary disease is caused by exposure to noxious gases or particles, especially cigarette smoke. Over time, this exposure damages the airways. The airways try to protect themselves by making more mucus. However, the lungs may slowly get damaged from chronic irritation. The increased mucus and lung damage can be permanent.
The World Health Organization (WHO) has recently developed a classification system for the severity of COPD. There are four stages of severity, as outlined below:
Stage 0, or at risk for COPD. These people have chronic cough and sputum production. Their lung function tests are still normal.
Stage I, or mild COPD. Individuals in this group have mild limitations in their airflow and changes in their lung function tests. They generally have chronic cough and sputum production.
Stage II, or moderate COPD. People at this stage have worsening of airflow that leads to shortness of breath with exertion. Their lung function tests show marked limitations.
Stage III, or severe COPD. Individuals at this stage have severe airflow limitations that impair their quality of life. Their lung function tests are markedly abnormal.
What are the causes and risks of the disease?
Cigarette smoking is the most common cause of COPD. The risk goes up with the amount of tobacco smoked, and the number of years of smoking. COPD is most common in countries where smoking is prevalent. It is less common in countries where people smoke less. Passive smoking, or exposure to secondhand smoke, does increase a person's risk for COPD.
Other risk factors for COPD include the following:
hereditary deficiency of alpha-1 antitrypsin, an enzyme involved in lung function
indoor air pollution, such as smoke from home cooking or home heating fuels
low birth weight
occupational dusts and chemicals
outdoor air pollution, such as motor vehicle exhaust fumes
severe childhood respiratory infections