Tanya Baylor, age 15, of Wilmington, Del., for her question:

WHAT CAUSES EMPHYSEMA?

Emphysema is a progressive respiratory disease that is charact riz d by coughing, shortness of breath and wheezing. It can develop into a condition that can make breathing extremely difficult. Although the exact cause is unknown, bronchial spasm, infection, irritation or a combination of the three seems to be contributory.

Heavy cigarette smokers often come down with emphysema, especially those exposed to polluted air. Children who suffer from bronchitis or asthma are also susceptible.

In recent years, emphysema had become a serious public health problem in terms of rapidly increasing numbers of disabilities.

In the course of emphysema, the passages leading to the air sacs of the lungs become narrowed. Air is trapped in the sacs and the tissues of the lungs lose their natural elasticity and undergo destructive changes. Symptoms akin to the common cold or asthmatic wheezing may result.

As the disease    progresses, the volume of residual air trapped in    the lungs increases and the volume of each breath decreases. The lungs may increase    in size     as they become unable to supply enough oxygen to the body  tissues.Treatment can give relief sometimes and increase the lungs' functioning capacity.