The pulmonary alveoli are lined with a highly surface-active lipid layer (predominantly phospholipid) that is essential for maintenance of normal alveolar architecture. Too little of this surface-active layer (known as surfactant) results in alveolar collapse and atelectasis. Too much surfactant may be the basis for the unusual disease, pulmonary alveolar proteinosis. In this disease, large amounts of lipidprotein material accumulate in the alveoli, lung volumes are diminished, gas transfer is impaired, and progressive pulmonary insufficiency results. Although pulmonary alveolar proteinosis is usually chronic and progressive, spontaneous remissions have occurred.1
As noted by Jenkins et al on p 74 of this issue, pulmonary symptoms and an abnormal chest x-ray film are usually present for some years before a definite diagnosis, usually by lung biopsy, is established.
Two types of treatment have been used: inhalation of mucolytic or proteolytic aerosols and lung lavage under general anesthesia. When there is progression of