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Emphysema

Definition

Emphysema is a lung disease that involves damage to the air sacs (alveoli) in the lungs. The air sacs are unable to completely deflate, 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
Decreased ability to exercise

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

Signs and tests

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:

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.

Low-flow oxygen can be used during exertion, continuously, or at night. Pulmonary rehabilitation can improve exercise tolerance and quality of life in the short-term. Lung transplantation is an option for patients with severe disease.

Carefully selected patients may be eligible for lung reduction surgery. This procedure removes the damaged portions of the lung, which allows the normal portions of the lung to expand more fully and take advantage of increased aeration. When successful, those who undergo the surgery report improvement in walking distance and quality of life.

Support Groups

Contact the American Lung Association for a support group near you.

Expectations (prognosis)

The outcome is better for patients with less damage to the lung. Prognosis is largely determined by initial shortness of breath, exercise tolerance, and results from lung function tests (spirometry). Death may occur from respiratory failure, pneumonia, or other complications.

Complications