Emphysema is a lung disease that involves damage to the air sacs (alveoli) in the lungs.

Cigarette smoking is the most common cause of emphysema. Tobacco smoke and other pollutants are thought to cause the release of chemicals from within the lungs that damage the walls of the air sacs. This damage becomes worse over time. Persons with this disease have air sacs in the lungs that are unable to fill with fresh air. This affects the oxygen supply to the body.

A naturally occurring substance in the lungs called alpha-1 antitrypsin may protect against this damage. People with alpha-1 antitrypsin deficiency are at an increased risk for this disease.

• Shortness of breath
• Chronic cough with or without sputum production
• Wheezing
• Decreased ability to exercise

• Anxiety
• Unintentional weight loss
• Ankle, feet, and leg swelling
• Fatigue

A physical examination may show wheezing, decreased breath sounds, or prolonged exhalation (exhalation takes more than twice as long as inspiration). The chest may be barrel-shaped. There may be signs of chronically insufficient oxygen levels in the blood.

These tests help confirm the diagnosis:

• Pulmonary function tests
• Chest x-ray
• Arterial blood gases showing low levels of oxygen in the blood (hypoxemia), and high levels of carbon dioxide (respiratory acidosis)

This disease may also alter the results of the following tests:

• Pulmonary ventilation/perfusion scan
• Chest CT scan