The cause of pulmonary alveolar proteinosis is unknown. It can occur with lung infection or an auto immune problem. It can also occur with certain cancers of the blood system or after exposure to high levels of silica or aluminum dust. There may be no symptoms, but sometimes there can be cough, fatigue, fever, shortness of breath, or weight loss.A procedure called a lung lavage can now help treat the effects of PAP. A whole lung lavage is done with general anesthesia and intubation with a specific tube allowing ventilation of one lung, while the other lung is repeatedly filled with 30 liters of saline. The liquid is then drained to clean out the material from the air sacs. The lavage is repeated in the other lung, either during the same procedure or at another time, depending on the experience and approach by the doctors. The procedure takes two to five hours to complete. Because of all of the fluid that is pumped in and out, the patient is given a water pill after the procedure to get rid of any water that is left .Risks include a drop in oxygen levels and infection, although 40 percent of patients only need one lavage. The other 60 percent may need to repeat the lavage until the surfacant is gone, as it can come back.