Emphysema

Definition

Emphysema is a lung disease that involves damage to the air sacs (alveoli). The air sacs are unable to completely deflate (hyperinflation) and are therefore unable to fill with fresh air to ensure adequate oxygen supply to the body.

Causes, incidence, and risk factors

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, affecting the exchange of oxygen and carbon dioxide in the lungs.

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.

Symptoms

• Shortness of breath
  
• Chronic cough with or without sputum production
  
• Wheezing
  

Additional symptoms that may be associated with this disease include the following:

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

Signs and tests
A physical examination may show decreased breath sounds, wheezing, and/or prolonged exhalation (exhalation takes more than twice as long as inspiration). There may be an increased front-to-back diameter of the chest, resemmbling a barrel shape. There may be signs of chronically insufficient oxygen levels in the blood.

These tests help confirm the diagnosis:

• Pulmonary function tests
  
• Chest X-ray
  

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

• Arterial blood gases showing reduced oxygen
  
• Pulmonary ventilation/perfusion scan
  
• Chest CT scan
  

Treatment

Smoking cessation is the most important and effective treatment. Only quitting smoking can stop the progression of lung damage once it has started. Medications used to improve breathing include bronchodilators (hand-held inhaler or nebulizer), diuretics, and corticosteroids. Antibiotics may be prescribed when respiratory infections occur. Influenza (flu) vaccines and Pneumovax (pneumonia vaccine) are recommended for people with emphysema.