Definition of Pulmonary alveolar proteinosis:

Pulmonary alveolar proteinosis is a rare disease in which a type of protein builds up in the air sacs (alveoli) of the lungs, making breathing difficult.

Causes, incidence, and risk factors:

In some cases, the cause of pulmonary alveolar proteinosis is unknown. In others, it occurs with lung infection or an immune problem. It also can occur with cancers of the blood system, and after exposure to high levels of environmental substances, such as silica or aluminum dust.

This rare disorder generally affects people ages 30 - 50 and is seen in men more often than in women. A form of the disorder is present at birth (congenital).

Symptoms:

• Cough
• Fatigue
• Fever
• Shortness of breath
• Weight loss

There may be no symptoms.

Signs and tests:

The doctor may hear crackles ("rales") in the lungs. Often, the physical examination is normal.

The following tests may be done:

• Bronchoscopy with saline wash of the lungs (lavage)
• Chest x-ray
• High-resolution CT scan of the chest
• Pulmonary function tests
• Open lung biopsy (surgical biopsy)

Treatment:

Treatment involves washing out the protein substance from the lung (whole-lung lavage) from time to time. Certain patients with this disease may need to have a lung transplant.

Research has shown some benefit to an experimental treatment that uses a blood-stimulating medication called granulocyte-macrophage colony stimulating factor (GM-CSF), which is known to be lacking in some patients with alveolar proteinosis.

Expectations (prognosis):

Some people with this condition go into remission. Others have respiratory failure that gets worse, and they may need a lung transplant. Up to 25% of people with this condition die within 5 years of being diagnosed.

Calling your health care provider:

Call your health care provider if you develop serious breathing symptoms. Shortness of breath that gets worse over time may signal that your condition is developing into a more serious medical emergency.