What Causes Hyperinflated Lungs?
Emphysema is the most common cause of hyperinflated lungs. Other causes include a severe asthma attack or a tumor of a major airway, such as the trachea or a bronchial tube.
Each of your lungs has about 300 million air sacs (alveoli). The walls of the alveoli contain elastic fibers that allow them to expand and contract like small balloons when you breathe. When the walls of the alveoli are damaged, they lose their elasticity and are unable to contract properly. This interferes with your ability to empty your lungs of air (exhale). As a result, too much air remains in the alveoli and overstretches (hyperinflates) them.
Overstretching may cause several air sacs to rupture, forming one large space instead of many smaller ones. Because the large air sacs can't force air out of your lungs as well as the small air sacs can, you have to breathe harder to get enough oxygen in your blood.
A doctor may diagnose hyperinflated lungs by a chest X-ray. It is important to note that the appearance of hyperinflation on a chest X-ray doesn't necessarily indicate emphysema. In older adults, the ribs can become fixed in an expanded position (barrel chest), making the lungs appear hyperinflated. A breathing (pulmonary function) test is needed to diagnose emphysema.
Treatment of hyperinflation is directed at the underlying cause, when possible. Although hyperinflation due to emphysema is irreversible, treatment — such as lung volume reduction surgery — may improve some signs and symptoms.