Rare lung disease in which abnormal accumulation of pulmonary surfactant occurs within the alveoli, interfering with gas exchange.Encyclopedia Entry for Pulmonary Alveolar Proteinosis :Pulmonary alveolar proteinosis. In some cases, the cause of PAP 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. People between 30 and 50 years old are most often affected. PAP is seen in men more often than in women. A form of the disorder is present at birth (congenital).Symptoms of PAP may include any of the following: Shortness of breath Cough Fatigue Fever, if there is lung infection Bluish skin ( cyanosis ) in severe cases Weight loss Sometimes, there are no symptoms.The health care provider will listen to the lungs with a stethoscope and 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 CT scan of the chest Lung function tests Open lung biopsy (surgical biopsy).Treatment involves washing out the protein substance from the lung (whole-lung lavage) from time to time. Some people may need a lung transplant. Avoiding dusts that might have caused the condition is also recommended. Another treatment that may be tried is a blood-stimulating drug called granulocyte-macrophage colony stimulating factor (GM-CSF), which is lacking in some people with alveolar proteinosis.These resources can provide more information on PAP: National Organization for Rare Disorders -- rarediseases.org/rare-diseases/pulmonary-alveolar-proteinosis PAP Foundation -- www.papfoundation.org.Some people with PAP go into remission. Others have a decline in lung infection ( respiratory failure ) that gets worse, and they may need a lung transplant.Call your provider if you develop serious breathing symptoms. Shortness of breath that gets worse over time may signal that your condition is developing into a medical emergency.PAP; Alveolar proteinosis; Pulmonary alveolar phospholipoproteinosis; Alveolar lipoproteinosis phospholipidosis.Interstitial lung disease - adults - discharge.Respiratory system Respiratory system.Levine SM. Alveolar filling disorders.