Unsuspected pulmonary alveolar proteinosis in a patient with a slow resolving pneumonia: A case report

Pulmonary alveolar proteinosis: a case report and world literature review

Pulmonary alveolar proteinosis (PAP) is a lung disorder which was first described in 1958 by Rosen et al. and is indeed rare disease with a prevalence of 0.1 per 100,000 individuals. PAP is characterized by abnormal accumulation of pulmonary surfactant in the alveolar space, which impairs gas exchange leading to a severe hypoxemia. Pulmonary surfactant is an insoluble proteinaceous material that is rich in lipids and stains positive with periodic acid-Schiff (PAS). The most common type of PAP is the so-called autoimmune or idiopathic type. It has been hypothesized that deficiency in granulocyte macrophage-colony stimulating factor (GM-CSF), as a result of the anti-GM-CSF antibody production, is strongly related to impaired surfactant recycling that leads to the accumulation of surfactant in the alveolar space. Its clinical course is variable from spontaneous remission in the best case scenario, going through the entire spectrum of disease severity, towards fatal respiratory failure. Whole lung lavage has been the gold standard therapy in PAP until the advent of GM-CSF. Although the first case was reported to be idiopathic, subsequent analysis revealed that Pneumocystis jirovecii, silica, and other inhalational toxins were able to trigger this reaction. In this study, we report the case of a 52-year-old man who developed PAP syndrome after a 2-year exposure to silica dust. Our review of the world literature that includes 363 cases reported until now, reflects the evolution of science and technology in determining different aetiologies and diagnostic tests that lead to an improved perspective in the life of these patients.