In the 1980s, approximately 2 million Americans were known to be afflicted with the chronic respiratory disease emphysema. By the dawn of the twenty-first century that number had ballooned to 3 million. What is perhaps even more disconcerting, however, is that the vast majority of individuals diagnosed with emphysema could have avoided the crippling disease by simply not smoking cigarettes.

Similar to most other respiratory ailments, smoking is a key factor in the onset of emphysema, accounting for more than 80 percent of all cases of the disease, which tends to develop gradually as the alveoli of the lungs become increasingly damaged by tobacco smoke. Thus, emphysema most commonly afflicts individuals over the age of 45, many of which began smoking as teenagers.

Emphysema is characterized by a deterioration of the elasticity of the lungs, which results in collapse of the alveolar walls and degeneration of the pulmonary capillaries. Consequently, large pockets of air may fill the lungs, but cannot be readily exhaled because the damage present in the organs hinders them from effectively pushing the air out. Early signs of the disease are breathlessness during physical exertion and a mild, chronic cough. Over time, the condition gets progressively worse, especially among smokers. It may become difficult to obtain enough air even when at rest, interest in eating may decrease because the process is made arduous by breathing problems, and the production of phlegm may become a constant occupation, aggravating the cough. Other common symptoms of emphysema include wheezing, tightness of the chest, intolerance to cold environments, swelling in the extremities, and a bluish hue to the skin related to insufficient exchange of gases. Without treatment, permanent disability can result, as can heart or respiratory failure leading to death.

The damage to the lungs caused by emphysema is irreversible. A successful lung transplant is the closest that a patient with the disease can currently come to a cure, but many individuals that such a procedure could potentially aid are not physically fit enough to undergo it. Accordingly, other, less invasive, treatments for emphysema are much more common. Bronchodilators are often recommended to help combat constriction of the airways, corticosteroids can soothe inflammation, and oxygen therapy is typically provided to individuals in an advanced state of the disease to counteract oxygen deficiency (hypoxemia).

Though emphysema is often associated with smoking, the disease can also occur due to other root causes. Most notably, research shows that some individuals suffering from emphysema exhibit a deficiency in the enzyme antitrypsin. Necessary to the integrity of lung tissue, antitrypsin usually functions by counteracting the destructive enzyme trypsin generated by bacteria. In cases where emphysema involves an antitrypsin deficiency, the disease is inherited and is typically of the panlobular (or panacinar) variety, in which deterioration of the alveoli occurs in all alveoli within the lobule concurrently, rather than beginning only in those areas near the center of the lobule (centrilobular emphysema).

Four stages of emphysema are outlined under the World Health Organization's classification system. Individuals with stage 0 emphysema are at risk for the disease and exhibit a chronic cough and sputum production, though function tests of their lungs are still normal. Those with stage I emphysema have a mild form of the disease. Similar to patients with stage 0 emphysema, they usually experience a cough that will not go away and abnormal production of sputum, but also have developed some limitation in airflow and alterations in their lung function tests. Stage II emphysema is more serious that stage I, but is still considered a moderate stage of the disease. Signs of stage II emphysema include shortness of breath upon exertion and marked limitations in airflow displayed during function testing of the lungs. Stage III is the most serious type of emphysema under the WHO system, patients with this advanced stage of the disease experiencing such severe limitation of airflow through the lungs that their quality of life is compromised and their lung function tests are highly abnormal.

Emphysema at 10x Magnification - In addition to smoking and a deficiency of the enzyme antitrypsin, other factors that have been identified as contributing to the development of emphysema in some patients include exposure to air pollution or various chemical fumes and irritants.

Emphysema at 20x Magnification - Some emphysema patients elect to undergo lung reduction surgery, a minimally invasive medical procedure that involves only a few small incisions, through which a small camera and stapling device can be inserted so that damaged portions of the lung can be cut away, providing healthy tissue with additional space for expansion.